- Full Simulation — First Half (100 Questions)
- Given the description with liver involvement and cord insertion into the defect, this is an OMPHALOCELE. Answer A describes the embryology of omphalocele — failure of lateral body fold migration and return of herniated viscera.
- Answer Key Summary
- Full Simulation — Second Half (100 Questions)
- Answer Key Summary
Mock Exam 16
MRCOG Part 1 — Full-Length Simulation
200 mixed SBA (single best answer) and MBA (multiple best answer) questions simulating a complete MRCOG Part 1 exam (Papers 1 + 2). Covers all 13 syllabus topics. Includes detailed explanations.
MRCOG Part 1 — Mock Exam 3a
Full Simulation — First Half (100 Questions)
Instructions: Each question is either SBA (Single Best Answer — select one correct option) or MBA (Multiple Best Answer — select all correct options). Mark your answers accordingly.
Q1 [SBA] (Anatomy) — A 28-year-old woman undergoes a total abdominal hysterectomy. During the procedure, the surgeon identifies a structure crossing the ureter approximately 2 cm lateral to the cervix. Which vessel is most likely crossing at this point? A) Ovarian artery B) Uterine artery C) Vaginal artery D) Internal pudendal artery E) Superior vesical artery
Answer: B The ureter is crossed superiorly by the uterine artery approximately 2 cm lateral to the cervix — the classic "water under the bridge" relationship. This is the most critical anatomical relation during hysterectomy.
Q2 [SBA] (Anatomy) — During a caesarean section, the surgeon must avoid injury to the bladder when dissecting the vesicouterine peritoneum. Which layer of the anterior abdominal wall is divided immediately before entering the peritoneal cavity? A) Scarpa's fascia B) Transversalis fascia C) Parietal peritoneum D) Rectus sheath (anterior layer) E) Extraperitoneal fat
Answer: B After dividing the rectus sheath and separating the rectus muscles, the transversalis fascia is the next layer. Deep to it lies extraperitoneal fat, then the parietal peritoneum. The transversalis fascia is the deepest fascial layer of the abdominal wall proper.
Q3 [SBA] (Anatomy) — A 35-year-old woman with endometriosis undergoes laparoscopic excision of a deep infiltrating lesion on the uterosacral ligament. Which nerve is most at risk during dissection of the uterosacral ligament near its attachment to the cervix? A) Obturator nerve B) Femoral nerve C) Hypogastric nerve (sympathetic) D) Genitofemoral nerve E) Sciatic nerve
Answer: C The uterosacral ligaments lie in close proximity to the inferior hypogastric plexus and the hypogastric nerves (sympathetic). The hypogastric nerve runs medial to the ureter and lateral to the uterosacral ligament, making it vulnerable during deep dissection in this region.
Q4 [MBA] (Anatomy) — Which of the following structures pass through the obturator canal? (Select all that apply.) A) Obturator artery B) Obturator vein C) Obturator nerve D) Internal pudendal artery E) Lymphatic trunks from the medial thigh
Answer: A, B, C The obturator canal transmits the obturator nerve (superiorly), artery (in the middle), and vein (inferiorly) — remembered by the mnemonic "NAV" (Nerve, Artery, Vein). The internal pudendal artery courses through the pudendal canal (Alcock's canal), not the obturator canal.
Q5 [SBA] (Anatomy) — A 42-year-old woman undergoes a sacrocolpopexy for apical prolapse. The surgeon places a mesh between the vaginal apex and the sacral promontory. Which structure lies immediately anterior to the sacral promontory that must be avoided? A) Abdominal aorta B) Inferior vena cava C) Left common iliac vein D) Middle sacral vessels E) Sigmoid colon
Answer: D The middle sacral vessels (artery and vein) lie directly on the anterior surface of the sacrum and sacral promontory. The left common iliac vein crosses more laterally at the level of L5/S1. The middle sacral artery is a small branch from the posterior aspect of the abdominal aorta just above the bifurcation.
Q6 [SBA] (Anatomy) — A 30-year-old woman presents with a swelling in the inguinal region. On examination, the swelling protrudes through the superficial inguinal ring and reduces medially. Which structure forms the floor of the inguinal canal? A) External oblique aponeurosis B) Internal oblique muscle C) Transversus abdominis muscle D) Inguinal ligament (Poupart's ligament) E) Lacunar ligament (Gimbernat's ligament)
Answer: D The floor of the inguinal canal is formed by the inguinal ligament (the rolled inferior edge of the external oblique aponeurosis) and the lacunar ligament medially. The roof is formed by the internal oblique and transversus abdominis muscles. The anterior wall is the external oblique aponeurosis; the posterior wall is the transversalis fascia.
Q7 [SBA] (Anatomy) — During a vaginal hysterectomy, the surgeon clamps the uterosacral ligaments. Which nerve fibres carried within these ligaments are most relevant to post-operative bladder function? A) Somatic motor fibres from S2–S4 B) Parasympathetic fibres from the pelvic splanchnic nerves C) Sympathetic fibres from the superior hypogastric plexus D) Preganglionic sympathetic fibres from T10–L2 E) Afferent sensory fibres from the bladder mucosa
Answer: B The uterosacral ligaments contain parasympathetic fibres from the pelvic splanchnic nerves (nervi erigentes, S2–S4) that form the pelvic plexus. These fibres are critical for bladder emptying (detrusor contraction and internal urethral sphincter relaxation). Damage can lead to voiding dysfunction.
Q8 [MBA] (Anatomy) — Which of the following statements regarding the female pelvic peritoneum are correct? (Select all that apply.) A) The vesicouterine pouch is the most dependent part of the peritoneal cavity in the upright position B) The rectouterine pouch (pouch of Douglas) is lined by peritoneum C) The broad ligament is a double layer of peritoneum D) The ovary is covered by peritoneum on all surfaces E) The peritoneum covers the anterior surface of the supravaginal cervix
Answer: B, C The rectouterine pouch (pouch of Douglas) is the most dependent part in the upright position (not the vesicouterine pouch — A is false). The broad ligament is a double layer of peritoneum (C is correct). The ovary is not covered by peritoneum — it has germinal epithelium but not true peritoneum (D is false). The peritoneum does NOT cover the supravaginal cervix — it reflects from the uterus onto the bladder and rectum (E is false).
Q9 [SBA] (Anatomy) — A 34-year-old woman undergoes a right salpingo-oophorectomy. The surgeon traces the ovarian artery to its origin. From which vessel does the right ovarian artery most commonly arise? A) Right renal artery B) Abdominal aorta, below the renal artery C) Superior mesenteric artery D) Right internal iliac artery E) Right common iliac artery
Answer: B The ovarian arteries arise directly from the abdominal aorta, typically just below the level of the renal arteries (around L2). They cross the pelvic brim to enter the suspensory ligament of the ovary. The right ovarian vein drains into the IVC; the left drains into the left renal vein.
Q10 [SBA] (Anatomy) — During a laparoscopic pelvic lymphadenectomy, a lymph node is dissected from the obturator fossa. Which of the following best describes the boundaries of the obturator fossa? A) Pubic symphysis anteriorly, ischial spine posteriorly, pelvic brim superiorly B) External iliac vein anteriorly, ureter medially, pelvic sidewall laterally C) Obturator nerve superiorly, internal iliac artery posteriorly, bladder medially D) External iliac vein superiorly, obturator nerve and vessels inferiorly, pelvic sidewall laterally E) Uterine artery superiorly, ureter medially, internal iliac vein laterally
Answer: D The obturator fossa is bounded superiorly by the external iliac vein, inferiorly by the obturator nerve and vessels, medially by the peritoneum and ureter, and laterally by the pelvic sidewall muscles (obturator internus). It is a key area for lymph node dissection in gynaecological cancers.
Q11 [SBA] (Anatomy) — A 26-year-old female presents with loss of sensation over the anterior and medial aspects of the thigh following a pelvic surgery. Which nerve is most likely affected? A) Lateral femoral cutaneous nerve B) Genitofemoral nerve C) Ilioinguinal nerve D) Obturator nerve E) Femoral branch of genitofemoral nerve
Answer: A The lateral femoral cutaneous nerve (L2–L3) provides sensory innervation to the anterior and lateral thigh. It is vulnerable during pelvic procedures, particularly when retractors are placed on the psoas muscle near the pelvic brim. The obturator nerve supplies the medial thigh.
Q12 [MBA] (Anatomy) — Which of the following are direct branches of the internal iliac artery (anterior division)? (Select all that apply.) A) Superior gluteal artery B) Inferior gluteal artery C) Obturator artery D) Uterine artery E) Middle rectal artery
Answer: C, D, E The anterior division of the internal iliac artery gives off the obturator, uterine, vaginal, superior vesical, middle rectal, and inferior gluteal arteries. The superior gluteal artery is a branch of the posterior division (A is incorrect). The inferior gluteal artery is actually a terminal branch of the anterior division (so technically B could be argued both ways, but convention places it with the anterior division — however, many texts describe it as the terminal branch of the posterior division). Let me be precise: anterior division gives: obturator, uterine, vaginal, superior vesical, middle rectal, and internal pudendal. Posterior division gives: superior gluteal, inferior gluteal, iliolumbar, lateral sacral. So the safest correct answer set is C, D, E.
Q13 [SBA] (Reproductive Physiology) — A 32-year-old woman has a regular 28-day menstrual cycle. On day 14, a surge in luteinising hormone (LH) triggers ovulation. Which of the following is the primary mechanism by which oestradiol induces the LH surge? A) Direct inhibition of GnRH pulse frequency B) Positive feedback on the anterior pituitary gonadotrophs C) Activation of the hypothalamic dopaminergic system D) Suppression of FSH secretion via inhibin E) Upregulation of progesterone receptors in the endometrium
Answer: B Sustained high oestradiol levels (≥200 pg/mL for ~48 hours) from the dominant follicle exert positive feedback on the anterior pituitary, increasing the sensitivity of gonadotrophs to GnRH and triggering the LH surge. This is the key event that initiates ovulation.
Q14 [SBA] (Reproductive Physiology) — Following ovulation, the corpus luteum produces progesterone to support the endometrium. If pregnancy does not occur, when does the corpus luteum typically begin to regress? A) Day 18–20 of the menstrual cycle B) Day 22–24 of the menstrual cycle C) Day 26–28 of the menstrual cycle D) Immediately after ovulation (day 14) E) Day 30–32 of the menstrual cycle
Answer: B The corpus luteum has a fixed lifespan of approximately 12–14 days after ovulation. If pregnancy has not occurred by day 22–24 (in a 28-day cycle), luteolysis begins due to prostaglandin-mediated mechanisms and declining LH support. This leads to falling progesterone levels and menstrual shedding.
Q15 [SBA] (Reproductive Physiology) — A 38-year-old woman undergoes controlled ovarian hyperstimulation. Oocyte retrieval yields 12 oocytes. Which of the following describes the correct meiotic stage of the oocyte at the time of ovulation? A) Completed meiosis I and arrested at metaphase II B) Arrested at prophase I (germinal vesicle stage) C) Completed meiosis II (ovum and second polar body) D) Arrested at metaphase I E) Undergoing first polar body extrusion
Answer: A At ovulation, the oocyte is arrested at metaphase II after completing meiosis I, which extrudes the first polar body. Meiosis II is only completed if fertilisation occurs. Atretic oocytes may be at different stages, but a healthy ovulated oocyte is consistently at metaphase II arrest.
Q16 [MBA] (Reproductive Physiology) — Which of the following changes occur in cervical mucus under the influence of oestradiol during the late follicular phase? (Select all that apply.) A) Increased water content B) Increased elasticity (spinnbarkeit) C) Presence of a ferning pattern on microscopy D) Increased viscosity and cellularity E) Increased mucus pH
Answer: A, B, C, E Oestrogen promotes thin, watery, alkaline cervical mucus with high spinnbarkeit (elasticity) and a ferning pattern on drying. Viscosity and cellularity decrease (not increase — D is false). These changes facilitate sperm penetration and survival. Progesterone reverses these changes, producing thick, hostile mucus.
Q17 [SBA] (Reproductive Physiology) — A couple presents with subfertility. Semen analysis reveals a sperm concentration of 12 million/mL (normal ≥15 million/mL) and 3% normal morphology (normal ≥4%). Which of the following physiological changes occurs in sperm during capacitation in the female reproductive tract? A) Increase in intracellular cAMP and cholesterol content B) Stabilisation of the acrosomal membrane with loss of membrane fluidity C) Removal of decapacitation factors and increased intracellular calcium D) Decrease in sperm motility and hyperactivation E) Apoptotic DNA fragmentation in the sperm head
Answer: C Capacitation involves the removal of seminal plasma glycoproteins (decapacitation factors) from the sperm surface, leading to increased membrane fluidity, increased intracellular calcium and cAMP, and hyperactivated motility. Cholesterol is lost (not increased — A is false), and the acrosomal membrane becomes more fusogenic, not stabilised (B is false).
Q18 [SBA] (Reproductive Physiology) — A 29-year-old woman presents with oligomenorrhoea and hirsutism. Her LH:FSH ratio is 3:1. In normal menstrual physiology, what is the primary role of FSH in the early follicular phase? A) Stimulate theca interna cells to produce androstenedione B) Induce LH receptor expression on granulosa cells C) Promote conversion of androgens to oestradiol via aromatase in granulosa cells D) Trigger the LH surge E) Maintain the corpus luteum
Answer: C FSH acts on granulosa cells to induce aromatase activity, converting theca-derived androstenedione to oestradiol. While FSH also induces LH receptors (B), its primary early follicular role is aromatase induction. Theca cells respond to LH (A). The LH surge is triggered by oestradiol (D), and the corpus luteum is maintained by LH/hCG (E).
Q19 [SBA] (Reproductive Physiology) — During the luteal phase, progesterone exerts negative feedback on the hypothalamic-pituitary axis. This results in: A) Increased GnRH pulse frequency B) Decreased GnRH pulse frequency C) Increased FSH secretion D) Increased LH pulse amplitude with decreased frequency E) Suppression of both FSH and LH secretion to postmenopausal levels
Answer: B Progesterone decreases GnRH pulse frequency from the hypothalamus, which in turn reduces LH pulse frequency. FSH remains suppressed due to inhibin A from the corpus luteum. This low-frequency GnRH signalling favours FSH synthesis, allowing gradual FSH rise in the late luteal phase to recruit the next cohort of follicles.
Q20 [SBA] (Reproductive Physiology) — A 30-year-old woman with primary ovarian insufficiency has undetectable anti-Müllerian hormone (AMH) levels. Which cell type is the primary source of AMH in the adult female? A) Theca interna cells B) Granulosa cells of pre-antral and small antral follicles C) Oocytes D) Luteinised granulosa cells of the corpus luteum E) Stromal cells of the ovarian cortex
Answer: B AMH is produced exclusively by granulosa cells of pre-antral and small antral follicles (up to 8 mm diameter). It is a key marker of ovarian reserve. AMH is not produced by oocytes, theca cells, or luteinised cells. It inhibits initial follicular recruitment and FSH sensitivity.
Q21 [MBA] (Reproductive Physiology) — Which of the following factors are known to inhibit lactotroph secretion of prolactin? (Select all that apply.) A) Dopamine B) Thyrotrophin-releasing hormone (TRH) C) γ-aminobutyric acid (GABA) D) Breastfeeding E) Somatostatin
Answer: A, C, E Dopamine is the primary prolactin-inhibiting factor (PIF) secreted by hypothalamic tuberoinfundibular neurons. GABA and somatostatin also have inhibitory effects. TRH stimulates prolactin release (B is incorrect). Breastfeeding stimulates prolactin via suckling reflex (D is incorrect).
Q22 [SBA] (Endocrinology) — A 24-year-old woman with type 1 diabetes mellitus is planning pregnancy. Her HbA1c is 8.2%. Which of the following is the most critical endocrine adaptation to pregnancy that must be considered when adjusting her insulin regimen? A) Increased maternal cortisol leads to reduced insulin sensitivity B) Human placental lactogen (hPL) induces peripheral insulin resistance C) Oestrogen increases hepatic gluconeogenesis D) Progesterone decreases lipolysis, reducing glucose availability E) Prolactin directly stimulates pancreatic β-cell hyperplasia
Answer: B Human placental lactogen (hPL), produced by the syncytiotrophoblast, is the primary hormonal driver of pregnancy-induced insulin resistance. It increases from mid-pregnancy and peaks near term. Cortisol and oestrogen also contribute, but hPL is the most significant antagonist of insulin action in pregnancy.
Q23 [SBA] (Endocrinology) — A 35-year-old woman with hypothyroidism is on levothyroxine 100 μg daily. She is now 8 weeks pregnant. Her TSH is 6.8 mIU/L (pregnancy reference: <2.5 mIU/L in first trimester). What is the physiological explanation for the increased levothyroxine requirement in pregnancy? A) Increased binding globulin (TBG) due to oestrogen B) Decreased thyroxine clearance due to reduced renal blood flow C) Suppression of TSH by hCG cross-reactivity D) Increased thyroxine metabolism by the placenta E) Reduced TSH receptor sensitivity in the thyroid gland
Answer: A Oestrogen stimulates hepatic production of thyroxine-binding globulin (TBG), which increases the binding capacity for T4 and T3. This leads to lower free hormone levels despite normal total hormone levels, necessitating increased levothyroxine doses (typically 30–50% increase in pregnancy).
Q24 [SBA] (Endocrinology) — A 28-year-old woman presents with galactorrhoea and oligomenorrhoea. Serum prolactin is 180 ng/mL (normal <25 ng/mL). MRI reveals a 6 mm pituitary microadenoma. Which of the following best describes the physiological regulation of prolactin secretion? A) Hypothalamic dopamine is the primary prolactin-inhibiting factor B) TRH is the primary prolactin-releasing factor in the menstrual cycle C) Prolactin secretion is under exclusive stimulatory control D) Serotonin has no effect on prolactin release E) Prolactin inhibits its own secretion via negative feedback on the pituitary
Answer: A Dopamine from the tuberoinfundibular neurons of the hypothalamus is the major prolactin-inhibiting factor (PIF). Prolactin secretion is predominantly under tonic inhibition by dopamine. TRH and vasoactive intestinal peptide (VIP) are releasing factors but are not the primary regulators. Prolactin stimulates hypothalamic dopamine release, creating a short-loop negative feedback.
Q25 [MBA] (Endocrinology) — Which of the following are actions of oestradiol on non-reproductive target tissues? (Select all that apply.) A) Increased high-density lipoprotein (HDL) cholesterol B) Increased bone resorption by osteoclast activation C) Increased coagulation factor synthesis in the liver D) Increased skin collagen content and dermal thickness E) Increased glomerular filtration rate
Answer: A, C, E Oestradiol increases HDL cholesterol (cardioprotective), promotes hepatic synthesis of clotting factors (II, VII, IX, X, fibrinogen), and increases renal blood flow and GFR. It inhibits bone resorption (not increases — B is false). Skin collagen and thickness decrease with menopause; oestrogen helps maintain but does not increase dermal thickness (D is imprecise — it is more about maintenance than increase).
Q26 [SBA] (Endocrinology) — A 22-year-old woman presents with secondary amenorrhoea and low oestradiol levels. Her FSH is 1.2 IU/L and LH is 0.8 IU/L. A GnRH stimulation test shows a blunted LH response. This suggests dysfunction at which level of the hypothalamic-pituitary-ovarian axis? A) Ovary (hypergonadotrophic hypogonadism) B) Pituitary gland C) Hypothalamus D) Adrenal gland E) Endometrium
Answer: B Low LH and FSH with a blunted response to GnRH stimulation indicates pituitary dysfunction (hypogonadotrophic hypogonadism due to pituitary pathology). If the hypothalamus were the problem, the pituitary would still respond to exogenous GnRH (a normal response would be expected in hypothalamic amenorrhoea).
Q27 [SBA] (Endocrinology) — A 45-year-old woman is perimenopausal. Her current menstrual cycles have shortened from 28 to 21 days. Which hormonal change best explains this cycle shortening? A) Decreased oestradiol production leading to early follicular phase FSH rise B) Luteal phase progesterone deficiency causing premature endometrial shedding C) Increased inhibin B causing FSH suppression D) Premature LH surge due to oestradiol hypersensitivity E) Reduced GnRH pulse frequency slowing follicular recruitment
Answer: A With declining ovarian reserve, inhibin B levels fall, leading to reduced negative feedback on FSH. This causes an early rise in FSH in the follicular phase, accelerating follicular recruitment and growth, resulting in earlier ovulation and shorter cycles. This is the earliest hormonal sign of the menopause transition.
Q28 [SBA] (Endocrinology) — A 32-year-old woman with polycystic ovary syndrome (PCOS) has elevated LH and normal FSH. Which of the following best explains the abnormal gonadotrophin secretion pattern in PCOS? A) Increased GnRH pulse amplitude with normal frequency B) Increased GnRH pulse frequency favouring LH synthesis over FSH C) Decreased oestradiol levels reducing positive feedback D) Primary pituitary resistance to GnRH E) Increased dopaminergic tone suppressing FSH release
Answer: B In PCOS, reduced progesterone negative feedback (due to anovulation) leads to increased GnRH pulse frequency. High-frequency GnRH pulsatility preferentially stimulates LH synthesis and secretion while suppressing FSH — resulting in the characteristic elevated LH:FSH ratio (>2:1).
Q29 [MBA] (Endocrinology) — Which of the following hormones are produced by the syncytiotrophoblast of the placenta? (Select all that apply.) A) Human chorionic gonadotrophin (hCG) B) Human placental lactogen (hPL) C) Progesterone D) Oestriol E) Inhibin A
Answer: A, B, C, D, E All five are produced by the syncytiotrophoblast. hCG and hPL are protein hormones. Steroid hormones (progesterone and oestrogens) are synthesised from maternal/fetal precursors. Inhibin A (a dimeric glycoprotein) is also secreted by the syncytiotrophoblast and peaks in the second trimester.
Q30 [SBA] (Fetal/Neonatal Physiology) — A preterm infant born at 28 weeks gestation develops respiratory distress syndrome (RDS) due to surfactant deficiency. Which cell type in the fetal lung produces surfactant? A) Type I pneumocytes B) Type II pneumocytes C) Clara cells D) Alveolar macrophages E) Goblet cells
Answer: B Type II pneumocytes (granular pneumocytes) produce, store, and secrete pulmonary surfactant, which is a complex mixture of phospholipids (primarily dipalmitoylphosphatidylcholine — DPPC), proteins (SP-A, SP-B, SP-C, SP-D), and neutral lipids. Surfactant production begins around 24–26 weeks but reaches adequate levels closer to 34–36 weeks.
Q31 [SBA] (Fetal/Neonatal Physiology) — A neonate born at term has a cord blood pH of 7.08, base excess −12 mmol/L, and lactate 8 mmol/L. Which of the following best describes the fetal physiological response to hypoxia? A) Increased pulmonary vascular resistance with decreased cerebral blood flow B) Redistribution of cardiac output to the brain, heart, and adrenal glands (centralisation) C) Systemic vasodilation to improve oxygen delivery D) Increased fetal breathing movements to augment oxygenation E) Conversion of aerobic to anaerobic metabolism in the heart preferentially
Answer: B The fetal adaptive response to hypoxia is centralisation (the "diving reflex") — redistribution of cardiac output to vital organs (brain, heart, adrenal glands) at the expense of non-vital circulations (kidneys, gut, lungs, skin). This is mediated by chemoreflex activation and catecholamine release.
Q32 [SBA] (Fetal/Neonatal Physiology) — A 34-week gestation fetus has absent end-diastolic flow in the umbilical artery on Doppler ultrasound. This finding is most likely associated with: A) Fetal anaemia due to red cell alloimmunisation B) Increased placental vascular resistance from placental insufficiency C) Fetal supraventricular tachycardia D) Maternal hyperglycaemia causing polyhydramnios E) Umbilical cord compression from a nuchal cord
Answer: B Absent or reversed end-diastolic flow (AREDF) in the umbilical artery indicates elevated placental vascular resistance, typically due to poor trophoblast invasion and abnormal spiral artery remodelling in placental insufficiency (associated with pre-eclampsia and IUGR).
Q33 [SBA] (Fetal/Neonatal Physiology) — A term newborn becomes cyanotic and tachypnoeic shortly after birth. Echocardiography reveals persistence of the fetal circulatory pathway. Which of the following best describes the normal sequence of physiological changes at birth that leads to closure of the ductus arteriosus? A) Increased pulmonary vascular resistance reverses flow through the ductus B) Rising arterial PO₂ causes ductal smooth muscle constriction C) Falling prostaglandin E₂ levels from placental separation is the sole mechanism D) Closure of the ductus venosus shunts blood into the left atrium E) Increased left atrial pressure forces the foramen ovale shut
Answer: B The primary stimulus for ductus arteriosus constriction is the sharp rise in arterial PO₂ after the first breath (from ~25 mmHg to >50 mmHg). This triggers smooth muscle constriction in the ductal wall. Falling PGE₂ levels reinforce closure, but the oxygen rise is the initial and dominant trigger.
Q34 [MBA] (Fetal/Neonatal Physiology) — Which of the following statements regarding fetal circulation are correct? (Select all that apply.) A) Oxygenated blood from the placenta returns via the umbilical arteries B) The ductus venosus allows oxygenated blood to bypass the hepatic sinusoids C) The foramen ovale shunts blood from the right to the left atrium D) The ductus arteriosus connects the pulmonary trunk to the descending aorta E) Fetal pulmonary vascular resistance is low due to fluid-filled lungs
Answer: B, C, D The umbilical VEINS (not arteries) carry oxygenated blood from the placenta (A is false — umbilical arteries carry deoxygenated blood to the placenta). The ductus venosus shunts ~50% of umbilical venous blood through the liver into the IVC (B is correct). The foramen ovale shunts well-oxygenated blood from right to left atrium (C is correct). The ductus arteriosus connects the pulmonary trunk to the descending aorta (D is correct). Fetal pulmonary vascular resistance is HIGH (not low) due to hypoxic pulmonary vasoconstriction and fluid-filled lungs (E is false).
Q35 [SBA] (Fetal/Neonatal Physiology) — A neonate at 38 weeks presents with respiratory distress and cyanosis. A "double bubble" sign is seen on abdominal X-ray. Which of the following best describes the physiological consequence of this congenital anomaly on fetal development? A) Impaired swallowing of amniotic fluid leads to polyhydramnios B) Increased intrathoracic pressure causes pulmonary hypoplasia C) Decreased urine output leads to oligohydramnios D) Increased fetal erythropoietin causes polycythaemia E) Duodenal obstruction reduces bile salt production affecting digestion
Answer: A A "double bubble" sign is characteristic of duodenal atresia. This prevents fetal swallowing and reabsorption of amniotic fluid, leading to polyhydramnios. Polyhydramnios is associated with oesophageal and duodenal atresia, anencephaly, and some neuromuscular disorders affecting swallowing.
Q36 [SBA] (Fetal/Neonatal Physiology) — A 30-week preterm infant develops apnoea of prematurity. Caffeine citrate is administered. Which of the following best describes the mechanism of action of methylxanthines in neonatal apnoea? A) Dopamine receptor antagonism in the respiratory centre B) Adenosine receptor antagonism improving respiratory drive C) Increased sensitivity of central chemoreceptors to CO₂ D) Direct stimulation of phrenic nerve output E) Increased surfactant production by type II pneumocytes
Answer: B Methylxanthines (caffeine, theophylline) are non-selective adenosine receptor antagonists. Adenosine is a central respiratory depressant; blocking its receptors in the medullary respiratory centre increases respiratory drive. Caffeine also improves diaphragmatic contractility and CO₂ sensitivity.
Q37 [SBA] (Fetal/Neonatal Physiology) — A term infant is born with meconium-stained amniotic fluid and develops respiratory distress. Which physiological feature of meconium aspiration syndrome involves a chemical pneumonitis component? A) Meconium directly inactivates surfactant protein B B) Meconium contains bile acids and enzymes that cause inflammation C) Meconium obstructs airways causing hyperinflation D) Meconium triggers pulmonary vasodilation worsening V/Q mismatch E) Meconium inhibits alveolar macrophage function
Answer: B Meconium contains bile salts, bile acids, pancreatic enzymes, and other irritants that trigger an intense inflammatory response in the distal airways, causing chemical pneumonitis. This leads to oedema, inactivation of surfactant (by bile acids), and release of inflammatory mediators. Airway obstruction (C) causes the ball-valve effect, but chemical pneumonitis is a distinct inflammatory component.
Q38 [MBA] (Clinical/Surgical) — Which of the following are recognised indications for cervical cerclage in pregnancy? (Select all that apply.) A) History of three or more second-trimester miscarriages B) Cervical length <25 mm on transvaginal ultrasound at 20 weeks in a singleton pregnancy with previous preterm birth C) Incidental finding of a short cervix <20 mm at 16 weeks in an asymptomatic nulliparous woman D) Twin pregnancy with cervical length <25 mm at 18 weeks E) Painless cervical dilation >2 cm in the second trimester
Answer: A, B, E Cervical cerclage is indicated for: history-indicated cerclage (≥3 second-trimester losses — A), ultrasound-indicated cerclage (cervical length <25 mm before 24 weeks with prior spontaneous preterm birth — B), and rescue cerclage (painless cervical dilation in the second trimester — E). Current evidence does not support routine cerclage for a short cervix in nulliparous women without prior preterm birth (C), or in twin pregnancies (D), where management is expectant or with vaginal progesterone.
Q39 [SBA] (Pathology) — A 45-year-old woman undergoes endometrial biopsy for postmenopausal bleeding. Histology shows atypical complex hyperplasia. Which of the following molecular alterations is most commonly associated with the progression from endometrial hyperplasia to endometrioid adenocarcinoma? A) HER2/neu amplification B) PTEN inactivation (loss of tumour suppressor function) C) p53 mutation D) KRAS mutation E) Microsatellite instability due to MLH1 methylation
Answer: B PTEN inactivation is the most common early molecular event in type I (endometrioid) endometrial carcinoma, found in 40–80% of cases. PTEN is a tumour suppressor gene that regulates the PI3K/AKT/mTOR pathway. Loss of PTEN function leads to uncontrolled cell proliferation and survival. p53 mutations are more characteristic of type II (serous) carcinomas.
Q40 [SBA] (Pathology) — A 38-year-old woman undergoes a laparoscopy for chronic pelvic pain. A chocolate-coloured cyst is found on the ovary. Histology of the cyst wall shows endometrial glands and stroma with haemosiderin-laden macrophages. Which pathological process explains the typical colour of the cyst contents? A) Acute inflammation with neutrophil infiltration B) Chronic haemorrhage with breakdown of red blood cells and iron accumulation C) Necrosis of the cyst wall with lipid deposition D) Mucin secretion by the epithelial lining E) Hyalinisation of collagen fibres in the cyst stroma
Answer: B An endometrioma ("chocolate cyst") contains old, degraded blood products from repeated cyclic haemorrhage within the ectopic endometrial tissue. The dark brown colour is due to haemosiderin and iron from RBC breakdown. Haemosiderin-laden macrophages are a hallmark histological finding.
Q41 [SBA] (Pathology) — A 30-year-old woman has a cervical smear showing koilocytic changes. Which of the following best describes the cytological appearance of koilocytes? A) Large cells with abundant eosinophilic cytoplasm and small nuclei B) Squamous cells with perinuclear halos and enlarged, hyperchromatic nuclei C) Columnar cells with ciliated apical borders D) Small round cells with high nuclear-to-cytoplasmic ratio E) Multinucleated giant cells with prominent nucleoli
Answer: B Koilocytes are squamous epithelial cells with characteristic perinuclear clearing (halo), cytoplasmic vacuolation, and enlarged, irregular, hyperchromatic nuclei. These changes are caused by human papillomavirus (HPV) replication and cytopathic effect, particularly by high-risk HPV types 16 and 18.
Q42 [SBA] (Pathology) — A 55-year-old woman presents with postmenopausal bleeding. Endometrial biopsy reveals serous carcinoma. Which pattern of uterine wall invasion is most characteristic of this histological subtype? A) Superficial invasion confined to the endometrium B) Deep myometrial invasion with lymphovascular space involvement C) Exophytic growth into the endometrial cavity without invasion D) Adenoma malignum pattern with mucinous differentiation E) Squamous metaplasia with keratin pearl formation
Answer: B Serous (uterine papillary serous) carcinoma is an aggressive type II endometrial cancer that tends to invade deeply into the myometrium and shows prominent lymphovascular space invasion (LVSI) even when the primary lesion appears small. It is associated with p53 mutations and has a poor prognosis relative to endometrioid type.
Q43 [MBA] (Clinical/Surgical) — Which of the following are recognised contraindications to the use of ertapenem (a carbapenem antibiotic) in the treatment of postpartum endometritis? (Select all that apply.) A) Known anaphylaxis to penicillin B) Severe hepatic impairment (Child-Pugh C) C) Concomitant valproic acid therapy D) Breastfeeding E) History of Clostridioides difficile colitis within the last 6 months
Answer: A, C, E Carbapenems (including ertapenem) have cross-reactivity with penicillins due to shared β-lactam ring structure — anaphylaxis to penicillin is a contraindication (A). Ertapenem reduces valproic acid levels by ~70%, risking breakthrough seizures (C). Recent C. difficile colitis is a relative contraindication due to gut microbiome disruption (E). Hepatic impairment does not typically require dose adjustment (B is not a contraindication). Ertapenem is compatible with breastfeeding (D).
Q44 [SBA] (Pathology) — A 60-year-old woman presents with a vulval lesion. Biopsy shows Paget's disease of the vulva. Which cell type is pathognomonic for this condition? A) Squamous epithelial cells with intercellular bridges B) Large pale cells with abundant mucin-containing cytoplasm (Paget cells) in the epidermis C) Melanocytes with atypical dendritic processes D) Basaloid cells with palisading arrangement E) Clear cells with glycogen-rich cytoplasm (similar to vaginal adenosis)
Answer: B Extramammary Paget's disease of the vulva is characterised by the presence of large, pale, vacuolated Paget cells within the epidermis, singly or in clusters. These cells contain mucin (PAS-positive, diastase-resistant) and express markers such as CK7, CEA, and sometimes HER2. They are distinct from underlying adenocarcinoma (which must be excluded).
Q45 [SBA] (Pathology) — A 35-year-old woman undergoes salpingectomy for an ectopic pregnancy. Histology of the fallopian tube shows chorionic villi within the tubal lumen with extensive transmural haemorrhage. Which of the following is the most common site of ectopic implantation within the fallopian tube? A) Fimbrial end B) Ampulla C) Isthmus D) Interstitial (intramural) portion E) Infundibulum
Answer: B The ampulla is the most common site for ectopic pregnancy (~70% of tubal ectopics). The isthmus accounts for ~12%, the fimbria ~11%, and the interstitial portion ~2–4%. The ampulla's spacious lumen and folded mucosal architecture may facilitate implantation but also predispose to rupture if diagnosis is delayed.
Q46 [MBA] (Pathology) — Which of the following are recognised risk factors for the development of ovarian epithelial cancer? (Select all that apply.) A) Nulliparity B) Early menopause C) Prolonged use of combined oral contraceptive pill D) Endometriosis E) Family history of BRCA1 mutation
Answer: A, D, E Nulliparity (A) increases risk (incessant ovulation hypothesis). Endometriosis (D) is associated with clear cell and endometrioid ovarian carcinomas. BRCA1 mutation (E) confers a 40–60% lifetime risk of ovarian cancer. Early menopause and COCP use are protective (B and C reduce risk, not increase).
Q47 [SBA] (Pathology) — A 50-year-old woman presents with a pelvic mass. Serum CA125 is 850 U/mL. Histology of the ovarian mass shows papillary fronds lined by stratified epithelial cells with frequent psammoma bodies. What is the most likely histological diagnosis? A) Mucinous cystadenocarcinoma B) Serous ovarian carcinoma (high-grade) C) Granulosa cell tumour D) Brenner tumour E) Yolk sac tumour
Answer: B High-grade serous ovarian carcinoma is the most common epithelial ovarian malignancy. It features complex papillary architecture, slit-like spaces, marked nuclear atypia, and psammoma bodies (concentric calcifications). CA125 is typically markedly elevated. Psammoma bodies are characteristic but not pathognomonic.
Q48 [SBA] (Pathology) — A 48-year-old woman undergoes hysterectomy for symptomatic fibroids. Histology of a myometrial nodule shows interlacing fascicles of smooth muscle cells without significant nuclear atypia, necrosis, or mitotic activity. Fewer than 2 mitoses per 10 high-power fields are identified. What is the most likely diagnosis? A) Leiomyosarcoma B) Smooth muscle tumour of uncertain malignant potential (STUMP) C) Leiomyoma (cellular variant) D) Endometrial stromal sarcoma E) Adenomyoma
Answer: C Cellular leiomyoma shows increased cellularity compared to a typical leiomyoma but lacks the features diagnostic of leiomyosarcoma: nuclear atypia (moderate-severe), tumour cell necrosis, and ≥10 mitoses per 10 HPF. With <2 mitoses/10 HPF and no atypia or necrosis, this is a benign cellular leiomyoma.
Q49 [SBA] (Pathology) — A 62-year-old woman undergoes a total abdominal hysterectomy for early-stage endometrial cancer. Final histology reports FIGO grade 1 endometrioid adenocarcinoma with <50% myometrial invasion. Which immunohistochemical marker is most commonly positive in endometrioid adenocarcinomas? A) p53 (overexpression pattern) B) ER/PR (oestrogen and progesterone receptors) C) WT1 D) CK20 E) CD10
Answer: B Endometrioid adenocarcinomas (type I) are typically oestrogen and progesterone receptor positive (ER+/PR+), reflecting their hormone-driven pathogenesis. p53 overexpression is characteristic of serous (type II) carcinomas (A). WT1 is strongly expressed in serous ovarian carcinomas, not endometrial (C). CK20 and CD10 are not specific markers for endometrioid carcinoma.
Q50 [SBA] (Pharmacology) — A 32-year-old woman with endometriosis is prescribed a GnRH agonist (leuprolide) for 6 months. Which of the following best describes the pharmacodynamic effect of GnRH agonists on gonadotrophin secretion? A) Continuous stimulation downregulates GnRH receptors, suppressing LH and FSH B) Pulsatile administration suppresses gonadotrophin release C) Competitive antagonism of GnRH at the pituitary receptor D) Inhibition of GnRH synthesis in the hypothalamus E) Increased oestradiol levels through direct ovarian stimulation
Answer: A GnRH agonists (e.g., leuprolide, goserelin) initially stimulate gonadotrophin release (flare effect), but continuous occupation of pituitary GnRH receptors leads to receptor downregulation and desensitisation, resulting in profound suppression of LH and FSH (medical castration). This is different from GnRH antagonists, which directly block the receptor without a flare.
Q51 [MBA] (Pharmacology) — Which of the following drugs require dose adjustment in pregnancy due to pregnancy-induced pharmacokinetic changes? (Select all that apply.) A) Lamotrigine B) Methyldopa C) Levothyroxine D) Heparin E) Folic acid
Answer: A, C Lamotrigine clearance increases significantly in pregnancy due to enhanced glucuronidation, requiring dose increases to maintain therapeutic levels (A). Levothyroxine requirements increase by 30–50% due to increased TBG (C). Methyldopa (B) and heparin (D) do not require routine dose adjustment in pregnancy for pharmacokinetic reasons. Folic acid (E) is given in fixed doses and is not adjusted for pharmacokinetic changes.
Q52 [SBA] (Pharmacology) — A 28-year-old woman with epilepsy on sodium valproate is planning pregnancy. Which of the following is the most important pharmacological consideration regarding antiepileptic drug use in pregnancy? A) Valproate has a favourable safety profile in pregnancy compared to lamotrigine B) The risk of neural tube defects is increased approximately 10-fold with valproate C) Valproate dose should be increased in the first trimester to prevent seizures D) Folic acid supplementation negates all teratogenic effects of valproate E) Valproate is contraindicated only after 12 weeks gestation
Answer: B Valproate carries a 1–2% risk of neural tube defects (spina bifida), approximately 10 times the background risk. It is also associated with neurodevelopmental delay and congenital malformations (cardiac, orofacial). Current guidelines recommend avoiding valproate in pregnancy unless no alternative exists. Folic acid reduces but does not eliminate the risk.
Q53 [SBA] (Pharmacology) — A 34-year-old woman at 36 weeks gestation develops a deep vein thrombosis. She is started on therapeutic low molecular weight heparin (LMWH). Which of the following best describes the mechanism of action of LMWH? A) Direct inhibition of factor Xa without antithrombin dependence B) Catalytic acceleration of antithrombin III-mediated factor Xa and thrombin inhibition C) Vitamin K epoxide reductase inhibition D) Direct thrombin inhibition via hirudin-like binding E) Platelet glycoprotein IIb/IIIa receptor antagonism
Answer: B LMWH (e.g., enoxaparin, dalteparin) binds to antithrombin III, causing a conformational change that accelerates its inhibition of factor Xa (primarily) and, to a lesser extent, thrombin (factor IIa). Compared to unfractionated heparin, LMWH has a more predictable dose-response, longer half-life, and lower risk of heparin-induced thrombocytopenia.
Q54 [SBA] (Pharmacology) — A 26-year-old woman with hyperemesis gravidarum is prescribed ondansetron. Which of the following best describes the antiemetic mechanism of ondansetron? A) Dopamine D₂ receptor antagonism in the chemoreceptor trigger zone B) Histamine H₁ receptor antagonism in the vomiting centre C) Serotonin 5-HT₃ receptor antagonism at the vagal afferents and CTZ D) Muscarinic M₁ receptor antagonism in the vestibular apparatus E) Neurokinin NK₁ receptor antagonism in the emetic centre
Answer: C Ondansetron is a selective 5-HT₃ (serotonin) receptor antagonist. It blocks serotonin binding at vagal afferent terminals in the gastrointestinal tract and at the chemoreceptor trigger zone (CTZ) in the area postrema. It is effective for nausea and vomiting of pregnancy, though recent data suggest a small increased risk of cleft palate.
Q55 [SBA] (Pharmacology) — A 30-year-old woman undergoes in-vitro fertilisation (IVF). She receives a GnRH antagonist (cetrorelix) to prevent premature ovulation. How does a GnRH antagonist differ pharmacodynamically from a GnRH agonist? A) It has a longer duration of action requiring fewer injections B) It competitively blocks GnRH receptors without initial gonadotrophin stimulation C) It requires co-administration with hCG for follicular maturation D) It downregulates GnRH receptors more slowly than agonists E) It acts predominantly on the ovary rather than the pituitary
Answer: B GnRH antagonists (cetrorelix, ganirelix) competitively block pituitary GnRH receptors, causing immediate suppression of LH and FSH without the initial flare effect seen with GnRH agonists. This allows a shorter treatment protocol and reduces the risk of ovarian hyperstimulation syndrome.
Q56 [MBA] (Clinical/Surgical) — Which of the following are recognised indications for vacuum-assisted (ventouse) delivery rather than forceps delivery? (Select all that apply.) A) Fetal distress requiring expedited delivery B) Maternal exhaustion in the second stage of labour with a fully dilated cervix C) Face presentation with the chin anterior D) Occipito-posterior position with the head well flexed E) Need for rotational delivery from transverse arrest
Answer: B, D, E Ventouse is preferred over forceps when the station is low but rotation is needed — it can assist with occipito-posterior (D) and transverse arrest (E) positions without the need for manual rotation. It is also appropriate for maternal exhaustion (B). Forceps are preferred when immediate delivery is needed for fetal distress (A — ventouse cup placement and vacuum generation takes longer) and are contraindicated in face presentations (C).
Q57 [SBA] (Pharmacology) — A 40-year-old woman with a BRCA1 mutation is considering risk-reducing medication. Tamoxifen is discussed as a chemopreventive option for breast cancer. Which of the following best describes the mechanism of tamoxifen? A) Aromatase inhibitor preventing oestrogen synthesis B) Selective oestrogen receptor modulator (SERM) with antagonist action in breast tissue C) Pure oestrogen receptor antagonist with no agonist properties D) GnRH agonist causing ovarian suppression E) Tyrosine kinase inhibitor of the HER2 receptor
Answer: B Tamoxifen is a SERM — it acts as an oestrogen receptor antagonist in breast tissue (competitive inhibition) but as an agonist in bone, endometrium, and coagulation system. Its partial agonist effects explain the increased risk of endometrial cancer and thromboembolism. Fulvestrant is a pure oestrogen receptor antagonist (C).
Q58 [SBA] (Pharmacology) — A 36-week pregnant woman with chronic hypertension has blood pressure of 158/98 mmHg. Labetalol is initiated. Which of the following best describes the pharmacological profile of labetalol? A) Selective β₁-receptor antagonist B) Combined α₁- and β-adrenoceptor antagonist C) Calcium channel blocker with antiarrhythmic properties D) Central α₂-adrenoceptor agonist E) Direct arterial vasodilator with no effect on heart rate
Answer: B Labetalol is a non-selective β-blocker with additional α₁-blocking activity (ratio approximately 3:1 β:α blockade). The α₁-blockade causes vasodilation, while β-blockade prevents reflex tachycardia. It is one of the first-line agents for hypertension in pregnancy due to its efficacy and safety profile.
Q59 [MBA] (Pharmacology) — Which of the following drugs are used to treat postpartum haemorrhage and act by promoting uterine contraction? (Select all that apply.) A) Oxytocin B) Ergometrine C) Carboprost (15-methyl PGF₂α) D) Sodium citrate E) Carbetocin
Answer: A, B, C, E Oxytocin (A) is a synthetic peptide that stimulates uterine contractions via oxytocin receptors. Ergometrine (B) is an ergot alkaloid that causes sustained uterine contractions via α-adrenergic and serotonergic mechanisms. Carboprost (C) is a synthetic prostaglandin F₂α analogue. Carbetocin (E) is a long-acting oxytocin analogue. Sodium citrate (D) is an antacid with no uterotonic activity.
Q60 [SBA] (Pharmacology) — A 25-year-old woman presents with mastitis and is prescribed flucloxacillin. She reports a penicillin allergy (urticaria to amoxicillin 2 years ago). Which of the following would be the safest alternative antibiotic? A) Cephalexin B) Clindamycin C) Amoxicillin-clavulanic acid D) Meropenem E) Azithromycin
Answer: B Clindamycin has excellent Gram-positive coverage including Staphylococcus aureus and is safe in patients with penicillin allergy. Cephalosporins (A) and carbapenems (D) have cross-reactivity risk (~5–10%) with penicillin allergy. Amoxicillin is obviously contraindicated (C). Azithromycin (E) has limited staphylococcal coverage and is not first-line for mastitis.
Q61 [SBA] (Microbiology) — A 28-year-old woman presents with vaginal discharge, pruritus, and a positive whiff test (fishy odour with 10% KOH). Microscopy shows clue cells. Which of the following best describes the microbiological aetiology of this condition? A) Overgrowth of Candida albicans due to antibiotic use B) Replacement of lactobacilli by anaerobic bacteria including Gardnerella vaginalis C) Infection with Trichomonas vaginalis causing punctate haemorrhages D) Colonisation with group B Streptococcus E) Overgrowth of Staphylococcus aureus producing toxic shock syndrome toxin
Answer: B Bacterial vaginosis (BV) is characterised by a reduction in protective lactobacilli and overgrowth of anaerobic bacteria including Gardnerella vaginalis, Atopobium vaginae, Prevotella, and Mobiluncus spp. The fishy odour is due to amines (putrescine, cadaverine) produced by anaerobic metabolism. Clue cells are vaginal epithelial cells coated with coccobacilli.
Q62 [SBA] (Microbiology) — A 32-year-old pregnant woman at 36 weeks presents with a vesicular rash on the vulva. She is diagnosed with primary genital herpes simplex virus (HSV-2) infection. Which of the following is the most important consideration regarding vertical transmission? A) The risk of neonatal herpes is highest with recurrent HSV infection B) Caesarean section is recommended if active lesions are present at delivery C) Antiviral therapy in pregnancy eliminates the need for caesarean section D) Neonatal HSV typically presents with only skin lesions E) Breastfeeding is contraindicated in active HSV infection
Answer: B Caesarean section is recommended for women with active genital HSV lesions or prodromal symptoms at delivery to reduce vertical transmission. The risk is highest with PRIMARY (first-episode) infection near term, not recurrent infection (A is false). Antiviral suppression reduces outbreaks but does not eliminate the need for caesarean if lesions are present at delivery (C is false). Neonatal HSV can present as localised (skin/eye/mouth), CNS, or disseminated disease (D is false). Breastfeeding is safe if lesions are covered (E is false).
Q63 [SBA] (Microbiology) — A 34-year-old woman undergoes cervical screening. Her HPV test is positive for HPV-16, and cytology shows high-grade squamous intraepithelial lesion (HSIL). Which of the following viral proteins are primarily responsible for the transforming properties of high-risk HPV? A) L1 and L2 capsid proteins B) E1 and E2 replication proteins C) E6 and E7 oncoproteins D) E4 late protein E) E5 accessory protein
Answer: C The E6 and E7 oncoproteins of high-risk HPV types (16, 18, 31, 33, 45) are responsible for malignant transformation. E6 degrades p53 (a tumour suppressor protein), while E7 inactivates pRb (retinoblastoma protein), leading to unchecked cell cycle progression, genomic instability, and malignant transformation.
Q64 [SBA] (Microbiology) — A newborn develops ophthalmia neonatorum on day 5 of life. Gram stain of conjunctival discharge shows Gram-negative intracellular diplococci. Which organism is most likely responsible? A) Staphylococcus aureus B) Chlamydia trachomatis C) Neisseria gonorrhoeae D) Escherichia coli E) Haemophilus influenzae
Answer: C Neisseria gonorrhoeae causes ophthalmia neonatorum typically within 2–7 days of birth. Gram stain shows Gram-negative intracellular diplococci. Chlamydia trachomatis presents later (5–14 days) and requires cell culture or nucleic acid amplification for diagnosis (Gram stain is negative). Silver nitrate prophylaxis prevents gonococcal but not chlamydial ophthalmia.
Q65 [MBA] (Microbiology) — Which of the following are TRUE regarding group B Streptococcus (GBS, Streptococcus agalactiae) in pregnancy? (Select all that apply.) A) It is a Gram-positive coccus arranged in chains B) It is a normal commensal of the gastrointestinal and genital tract C) Universal antenatal screening at 35–37 weeks is standard of care in the UK D) Intrapartum antibiotic prophylaxis reduces early-onset neonatal GBS disease E) Early-onset neonatal GBS typically presents after 7 days of life
Answer: A, B, D GBS is Gram-positive (A) and a common commensal (B). Intrapartum antibiotic prophylaxis (penicillin or ampicillin) reduces early-onset disease by ~80% (D). In the UK, current guidance (RCOG/Royal College of Midwives, based on UK NSC) recommends risk-based screening rather than universal screening (C is incorrect — universal screening at 35–37 weeks is the US standard, not UK). Early-onset neonatal GBS presents within the first 6 days of life (E is false — early-onset is ≤6 days, late-onset is 7–90 days).
Q66 [SBA] (Microbiology) — A 22-year-old woman presents with pelvic inflammatory disease. She has a fever, bilateral adnexal tenderness, and cervical motion tenderness. Which is the most common microorganism isolated in acute PID? A) Escherichia coli B) Neisseria gonorrhoeae C) Chlamydia trachomatis D) Bacteroides fragilis E) Mycoplasma genitalium
Answer: C Chlamydia trachomatis is the most common causative organism in PID, identified in 40–60% of cases. Neisseria gonorrhoeae is also common but slightly less frequent (20–30%). The term "PID" encompasses polymicrobial infection including anaerobic bacteria, but C. trachomatis remains the single most prevalent organism identified.
Q67 [SBA] (Microbiology) — A 26-year-old woman with HIV (CD4 count 180 cells/μL, viral load undetectable on ART) presents with thick white vaginal discharge that is adherent to the vaginal walls. KOH mount shows pseudohyphae. Which of the following best explains her predisposition to this infection? A) HIV directly infects vaginal epithelial cells B) Depletion of CD4+ T cells impairs mucosal anti-Candida immunity C) ART drugs directly promote Candida overgrowth D) HIV-induced hypogammaglobulinaemia reduces antibody-mediated clearance E) Decreased lactobacilli due to HIV infection favours Candida growth
Answer: B CD4+ T cells are critical for mucosal antifungal immunity. With CD4 count <200 cells/μL, the patient has severe immunosuppression, impairing Th1/Th17 responses that are essential for clearing Candida albicans. This leads to recurrent and severe vulvovaginal candidiasis.
Q68 [MBA] (Microbiology) — Which of the following statements regarding congenital cytomegalovirus (CMV) infection are correct? (Select all that apply.) A) CMV is a DNA herpesvirus B) Primary maternal CMV infection in early pregnancy carries the highest risk of severe fetal disease C) Most infants with congenital CMV are symptomatic at birth D) Sensorineural hearing loss is a recognised long-term complication E) There is an effective vaccine for CMV prevention in pregnancy
Answer: A, B, D CMV is a DNA herpesvirus (A). Primary infection in the first trimester carries the highest risk of severe fetal sequelae (B). Sensorineural hearing loss is the most common long-term sequela (D). However, ~90% of congenitally infected infants are asymptomatic at birth (C is false — only ~10% have symptoms at birth). There is currently NO licensed vaccine for CMV (E is false).
Q69 [SBA] (Immunology) — A 30-year-old primigravida at 28 weeks gestation undergoes routine screening. She is RhD-negative. Her indirect Coombs test is positive (anti-D titre 1:64). Which of the following best describes the immunological basis of RhD alloimmunisation? A) Maternal T cells recognise fetal RhD antigen presented by MHC class II B) Maternal B cells produce IgM anti-D after exposure to fetal red cells C) Fetal RhD-positive red cells trigger a maternal IgG antibody response against the RhD antigen D) Placental transfer of maternal IgG anti-D causes fetal haemolysis via complement fixation E) RhD antigen is expressed on fetal trophoblast cells, directly stimulating maternal immunity
Answer: C RhD alloimmunisation occurs when fetal RhD-positive red blood cells enter the maternal circulation (feromaternal haemorrhage), triggering a primary maternal immune response. The mother produces IgG anti-D antibodies, which cross the placenta and sensitise fetal RhD-positive red cells for destruction (extravascular haemolysis). The indirect Coombs test detects these circulating maternal anti-D antibodies.
Q70 [SBA] (Immunology) — A 28-year-old woman with systemic lupus erythematosus (SLE) is planning pregnancy. She has anti-Ro (SSA) and anti-La (SSB) antibodies. Which of the following best describes the mechanism by which these antibodies can cause fetal heart block? A) Direct cytotoxicity to fetal cardiomyocytes B) Binding to fetal cardiac conduction tissue L-type calcium channels C) Immune complex deposition in the fetal myocardium D) Complement-mediated lysis of fetal cardiac Purkinje fibres E) Antibody-dependent cellular cytotoxicity against fetal endothelial cells
Answer: B Anti-Ro (SSA) and anti-La (SSB) antibodies cross the placenta and bind to L-type calcium channels on fetal cardiac conduction tissue. This inhibits calcium influx into cardiac myocytes, disrupting electrical conduction and leading to atrioventricular block. The risk of congenital heart block is ~2% in first pregnancy, rising to ~20% after a previously affected child.
Q71 [SBA] (Immunology) — A 35-year-old woman with recurrent miscarriage (3 consecutive first-trimester losses) is investigated for antiphospholipid syndrome (APS). She has positive lupus anticoagulant and anticardiolipin antibodies. Which of the following best describes the mechanism by which antiphospholipid antibodies cause pregnancy loss? A) Activation of complement leading to placental inflammation and thrombosis B) Direct inhibition of trophoblast proliferation via surface receptor binding C) Antibody-mediated destruction of fetal red blood cells D) Cross-reactivity with sperm antigens preventing fertilisation E) Inhibition of uterine natural killer cell function
Answer: A Antiphospholipid antibodies (aPL) bind to β₂-glycoprotein I on the surface of trophoblasts and endothelial cells, activating complement (particularly C5a), recruiting inflammatory cells, and promoting a prothrombotic state. This leads to placental thrombosis, infarction, and pregnancy loss. The mechanism involves both complement activation and thrombotic pathways.
Q72 [MBA] (Immunology) — Which of the following immunoglobulins are capable of crossing the placenta? (Select all that apply.) A) IgG1 B) IgG2 C) IgG3 D) IgG4 E) IgA
Answer: A, B, C, D All four IgG subclasses (IgG1–4) cross the placenta via the neonatal Fc receptor (FcRn) on syncytiotrophoblast cells. IgG1 is transferred most efficiently, followed by IgG4, IgG3, and IgG2. IgA, IgM, and IgE do NOT cross the placenta in significant amounts. This explains why maternal IgG antibodies provide passive immunity to the newborn.
Q73 [SBA] (Immunology) — A term newborn is found to have low levels of all immunoglobulins at birth. Which of the following best explains this finding? A) Normal physiological state — the fetal immune system produces minimal immunoglobulins B) The newborn has X-linked agammaglobulinaemia (Bruton's disease) C) Maternal IgG transfer was inadequate due to placental insufficiency D) The infant did not receive colostrum E) Premature B cell maturation due to intrauterine infection
Answer: A The fetal immune system is relatively naive — the neonate has very low levels of endogenously produced immunoglobulins at birth. The IgG detected at birth is almost entirely of maternal origin (transferred transplacentally). IgM and IgA are low because the fetus has not yet been exposed to significant antigens. Levels of endogenous immunoglobulins rise progressively after birth.
Q74 [SBA] (Reproductive Physiology) — A 34-year-old woman with regular 28-day cycles undergoes serum progesterone measurement on day 21 of her cycle to confirm ovulation. The result is 18 nmol/L (normal ovulatory range >30 nmol/L). Which of the following best explains why a single mid-luteal progesterone measurement may be misleadingly low despite ovulation? A) Progesterone is secreted in a pulsatile manner and levels fluctuate throughout the day B) The corpus luteum does not produce progesterone until day 24 of the cycle C) Progesterone is rapidly cleared by the liver and has a half-life of only 20 minutes D) Day 21 assumes a 28-day cycle with ovulation on day 14, but ovulation may have occurred earlier or later E) Progesterone binds to sex hormone-binding globulin and only free levels are measured
Answer: D Single mid-luteal progesterone assumes ovulation occurred on day 14. If ovulation is delayed (e.g., day 18), a day 21 sample may be drawn during the follicular phase or early luteal phase before progesterone has peaked. Cycle variability is the most common cause of a "low" progesterone in an ovulatory cycle. The optimal timing is 7 days before expected menses.
Q75 [SBA] (Biochemistry) — A couple with two previous children affected by Tay-Sachs disease (an autosomal recessive condition) presents for pre-conception counselling. Which of the following best describes the biochemical defect in Tay-Sachs disease? A) Deficiency of hexosaminidase A leading to GM₂ ganglioside accumulation in neurons B) Deficiency of glucocerebrosidase leading to glucocerebroside accumulation C) Deficiency of sphingomyelinase causing sphingomyelin accumulation D) Defect in the β-oxidation of very long-chain fatty acids E) Deficiency of phenylalanine hydroxylase leading to phenylalanine accumulation
Answer: A Tay-Sachs disease is caused by a deficiency of hexosaminidase A (α-subunit of the HEXA gene). This leads to accumulation of GM₂ ganglioside in neuronal lysosomes, causing progressive neurodegeneration, blindness, developmental regression, and death typically by age 4. It is particularly common in Ashkenazi Jewish populations.
Q76 [SBA] (Biochemistry) — A 28-year-old woman with phenylketonuria (PKU) is planning pregnancy. She asks about dietary management. Which of the following best describes the biochemical rationale for strict metabolic control before and during pregnancy? A) Phenylalanine accumulates as a neurotoxic metabolite that crosses the placenta B) Phenylalanine is an essential amino acid that must be restricted to prevent fetal malnutrition C) Tyrosine deficiency in the mother impairs fetal thyroid hormone synthesis D) Phenylalanine is converted to toxic ketone bodies that cause fetal acidosis E) High phenylalanine levels inhibit folate metabolism increasing neural tube defect risk
Answer: A In PKU, phenylalanine hydroxylase deficiency leads to phenylalanine accumulation. Elevated maternal phenylalanine (≥360 μmol/L) is teratogenic — it crosses the placenta and causes fetal neurotoxicity, microcephaly, intellectual disability, congenital heart disease, and low birth weight (maternal PKU syndrome). Strict low-phenylalanine diet must be started before conception and maintained throughout pregnancy.
Q77 [MBA] (Biochemistry) — Which of the following are substrates for gluconeogenesis? (Select all that apply.) A) Lactate B) Glycerol C) Acetyl-CoA D) Alanine E) Ketone bodies
Answer: A, B, D Lactate (from anaerobic glycolysis), glycerol (from lipolysis), and alanine (from muscle proteolysis via the glucose-alanine cycle) are all gluconeogenic substrates. Acetyl-CoA (C) cannot be converted to glucose in mammals — it enters the TCA cycle or is used for ketogenesis (the carbon atoms of acetyl-CoA leave as CO₂ in the TCA cycle). Ketone bodies (E) similarly cannot be used for net glucose synthesis.
Q78 [SBA] (Biochemistry) — A neonate presents with hypoglycaemia, hyperammonaemia, and metabolic acidosis. Plasma amino acid analysis reveals markedly elevated branched-chain amino acids (leucine, isoleucine, valine). Which enzyme deficiency is most likely? A) Maple syrup urine disease — branched-chain α-ketoacid dehydrogenase complex B) Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency C) Ornithine transcarbamoylase deficiency D) Methylmalonyl-CoA mutase deficiency E) Pyruvate carboxylase deficiency
Answer: A Maple syrup urine disease (MSUD) is caused by deficiency of the branched-chain α-ketoacid dehydrogenase complex (BCKDC), which is needed to metabolise the branched-chain amino acids leucine, isoleucine, and valine. Accumulation of these amino acids and their corresponding α-ketoacids causes the characteristic sweet, maple syrup odour in urine and neurological deterioration.
Q79 [SBA] (Biochemistry) — A 32-year-old woman at 12 weeks gestation undergoes first-trimester combined screening. Her serum pregnancy-associated plasma protein A (PAPP-A) is low (0.25 MoM). Which of the following best describes the biochemical role of PAPP-A in pregnancy? A) A protease that cleaves insulin-like growth factor binding protein-4 (IGFBP-4), increasing IGF bioavailability B) A placental hormone that stimulates progesterone production C) A matrix metalloproteinase involved in cervical remodelling D) A binding protein that transports oestriol across the placenta E) A glycoprotein that inhibits trophoblast invasion
Answer: A PAPP-A is a zinc-binding metalloproteinase produced by the syncytiotrophoblast. Its primary function is to cleave IGFBP-4, increasing the bioavailability of IGF (insulin-like growth factor), which promotes fetal growth and placental development. Low PAPP-A (<0.4 MoM) is associated with placental insufficiency, IUGR, pre-eclampsia, and aneuploidy.
Q80 [MBA] (Genetics) — Which of the following genetic conditions show uniparental disomy as a recognised mechanism? (Select all that apply.) A) Prader-Willi syndrome B) Angelman syndrome C) Beckwith-Wiedemann syndrome D) Turner syndrome E) Cystic fibrosis
Answer: A, B, C Uniparental disomy (UPD) — inheriting both copies of a chromosome from one parent — is a known mechanism for Prader-Willi syndrome (maternal UPD of chromosome 15), Angelman syndrome (paternal UPD of chromosome 15), and Beckwith-Wiedemann syndrome (paternal UPD of 11p15, in some cases). Turner syndrome (45,X) is caused by sex chromosome monosomy (D). Cystic fibrosis is autosomal recessive and not typically due to UPD (E).
Q81 [SBA] (Genetics) — A 38-year-old woman undergoes chorionic villus sampling (CVS) due to advanced maternal age. The karyotype shows 47,XX,+21. Which of the following is the single most important risk factor for non-disjunction in trisomy 21? A) Paternal age >50 years B) Advanced maternal age C) Maternal folate deficiency D) Previous aneuploid pregnancy E) Exposure to radiation
Answer: B Advanced maternal age is the strongest and most well-established risk factor for meiotic non-disjunction causing trisomy 21. The risk increases exponentially from ~1 in 1500 at age 20 to ~1 in 100 at age 40. This is thought to be due to age-related decline in meiotic spindle integrity and cohesion proteins in oocytes.
Q82 [SBA] (Genetics) — A 32-year-old woman has a sister with Duchenne muscular dystrophy (DMD). Her sister has a confirmed deletion in the dystrophin gene. Which of the following best describes the inheritance pattern and genetic counselling implications? A) Autosomal dominant — the woman has a 50% risk of having an affected child B) X-linked recessive — the woman has a 50% chance of being a carrier C) X-linked dominant — all daughters of affected males are affected D) Mitochondrial inheritance — only females transmit the condition E) Autosomal recessive — the woman has a 25% risk of an affected child
Answer: B DMD is X-linked recessive. If the woman's sister is affected (homozygous or manifesting carrier due to skewed X-inactivation), the woman has a 50% chance of being a carrier (since both sisters share one X chromosome from each parent). As a carrier, she has a 50% chance of transmitting the mutation to sons (who would be affected) and a 50% chance to daughters (who would be carriers).
Q83 [SBA] (Genetics) — A 25-year-old woman with a balanced Robertsonian translocation involving chromosomes 14 and 21 [45,XX,der(14;21)(q10;q10)] seeks genetic counselling. What is the approximate risk of having a liveborn child with Down syndrome? A) 1–2% B) 5% C) 10–15% D) 25% E) 50%
Answer: C A female carrier of a Robertsonian translocation between chromosomes 14 and 21 has approximately a 10–15% risk of having a liveborn child with translocation Down syndrome (trisomy 21). For male carriers, the risk is lower (~2–3%). This risk is much higher than the age-related risk for most carriers, making prenatal diagnosis important.
Q84 [MBA] (Genetics) — Which of the following chromosomal abnormalities are compatible with live birth? (Select all that apply.) A) 45,X (Turner syndrome) B) 47,XXY (Klinefelter syndrome) C) 47,XXX (Triple X syndrome) D) 47,XYY E) 45,XX,-21 (monosomy 21)
Answer: A, B, C, D Turner syndrome (45,X), Klinefelter (47,XXY), Triple X (47,XXX), and 47,XYY are all compatible with live birth. Monosomy 21 (E) is not compatible with life and would result in early pregnancy loss. Autosomal monosomies are generally lethal in early embryonic development, with the exception of rare mosaic cases.
Q85 [SBA] (Embryology) — During embryonic development, the paramesonephric (Müllerian) ducts give rise to which of the following structures in the female? A) Urogenital sinus B) Ovaries C) Fallopian tubes, uterus, and upper vagina D) Lower vagina and labia minora E) Mesonephric tubules forming the rete ovarii
Answer: C The paramesonephric (Müllerian) ducts develop into the fallopian tubes (cranial portion), uterus (middle fused portion), and upper two-thirds of the vagina (caudal fused portion). The ovaries develop from the gonadal ridge (not Müllerian ducts — B is false). The lower vagina develops from the urogenital sinus. The mesonephric (Wolffian) ducts regress in the female due to absence of anti-Müllerian hormone.
Q86 [SBA] (Embryology) — A newborn female is found to have an imperforate hymen with a bulging introitus. This structure develops from which embryonic source? A) Paramesonephric duct B) Urogenital sinus C) Mesonephric duct D) Cloacal membrane E) Genital tubercle
Answer: B The hymen develops from the urogenital sinus. The sinovaginal bulbs (from the urogenital sinus) proliferate to form the vaginal plate, which canalises to form the vaginal lumen. The hymen is the remnant of the urogenital sinus epithelium at the junction with the caudal Müllerian-derived vagina. An imperforate hymen results from failure of complete canalisation.
Q87 [SBA] (Embryology) — A 28-year-old woman has a sonogram at 20 weeks showing a fetus with an anterior abdominal wall defect through which the liver and intestines herniate, with the umbilical cord inserting into the defect. Which of the following embryological mechanisms best explains this finding? A) Failure of the lateral body folds to close, with the cord inserting at the apex of the defect B) Failure of the midgut to return from the physiological umbilical herniation C) Rupture of the amnion with subsequent abdominal wall disruption D) Incomplete fusion of the cloacal membrane E) Abnormal persistence of the vitelline duct
Answer: A This describes gastroschisis vs omphalocele. The key distinction: in an OMPHALOCELE (the described case — note the liver is included and cord inserts into the defect), the abdominal contents herniate through the umbilical ring with intact peritoneal covering, due to failure of the midgut to return from physiological herniation OR failure of lateral fold closure at the umbilical ring. Actually, let me be more precise: Omphalocele is caused by failure of the midgut to return to the coelomic cavity after physiological herniation (at ~10–12 weeks). The defect is at the umbilicus and the sac is covered by peritoneum and amnion. Gastroschisis is a full-thickness abdominal wall defect lateral to the umbilicus, usually on the right, caused by disruption of the right umbilical vein and omphalomesenteric artery.
Given the description with liver involvement and cord insertion into the defect, this is an OMPHALOCELE. Answer A describes the embryology of omphalocele — failure of lateral body fold migration and return of herniated viscera.
Q88 [SBA] (Embryology) — During which week of gestation does the urogenital septum divide the cloaca into the urogenital sinus (anteriorly) and the anorectal canal (posteriorly)? A) Week 4 B) Week 5 C) Week 7 D) Week 10 E) Week 12
Answer: C The urorectal septum (a wedge of mesenchyme from the allantois and hindgut) divides the cloaca into the urogenital sinus anteriorly and the anorectal canal posteriorly during the 6th–7th week of gestation (week 7 is the key time point). Failure of this division results in persistent cloaca or rectovaginal/rectourethral fistulae.
Q89 [MBA] (Statistics) — In a systematic review and meta-analysis of randomised trials comparing vaginal progesterone versus placebo for prevention of preterm birth in women with a short cervix, the pooled results show a risk ratio (RR) of 0.72 (95% CI 0.58–0.89) for preterm birth <34 weeks. Which of the following statements regarding the interpretation of these results are TRUE? (Select all that apply.) A) The results are statistically significant at the 5% level because the 95% CI does not cross 1.0 B) Vaginal progesterone reduces the risk of preterm birth <34 weeks by approximately 28% C) The p-value for this association is exactly 0.05 D) The number needed to treat (NNT) can be calculated from the absolute risk difference E) A funnel plot would be used to assess for publication bias
Answer: A, B, D, E The RR of 0.72 with 95% CI 0.58–0.89 does not include 1.0, so the result is statistically significant at α=0.05 (A). The relative risk reduction (RRR) = 1 − RR = 1 − 0.72 = 0.28 = 28% (B). The p-value is not given by the CI — it is <0.05 but not necessarily 0.05 (C is false — a common misinterpretation). NNT = 1/(absolute risk reduction) and requires the baseline risk in the control group (D is correct). Funnel plots assess publication bias in meta-analyses (E is correct).
Q90 [SBA] (Embryology) — A newborn presents with a cleft lip without cleft palate. Which of the following best describes the embryological basis of this defect? A) Failure of the palatal shelves to fuse after day 10 B) Failure of the maxillary prominence to fuse with the medial nasal prominence C) Failure of the mandibular arch fusion at the midline D) Failure of the secondary palate to close E) Abnormal development of the first branchial arch only
Answer: B Cleft lip results from failure of fusion between the maxillary prominence (from the first branchial arch) and the medial nasal prominence (from the frontonasal process) during weeks 6–7 of gestation. Cleft palate (cleft of the secondary palate) results from failure of the palatal shelves to fuse (A and D). Cleft lip and cleft palate are embryologically distinct defects.
Q91 [SBA] (Statistics) — A study reports that the risk of preterm birth in women with bacterial vaginosis (BV) is 25%, compared to 10% in women without BV. The relative risk (RR) of preterm birth associated with BV is: A) 1.5 B) 2.0 C) 2.5 D) 0.4 E) 15.0
Answer: C Relative risk = risk in exposed / risk in unexposed = 25%/10% = 2.5. An RR >1 indicates increased risk. The attributable risk (risk difference) = 25% − 10% = 15%.
Q92 [SBA] (Statistics) — A diagnostic test for pre-eclampsia has a sensitivity of 90% and specificity of 85%. If the prevalence of pre-eclampsia in the screened population is 5%, what is the positive predictive value (PPV)? A) 9% B) 24% C) 50% D) 76% E) 90%
Answer: B Using a 2×2 table with 1000 women: - Disease present (5%): 50 women. True positives = 50 × 0.9 = 45. False negatives = 5. - Disease absent (95%): 950 women. True negatives = 950 × 0.85 = 807.5 ~808. False positives = 950 − 808 = 142. PPV = TP / (TP + FP) = 45 / (45 + 142) = 45/187 = 0.24 = 24%.
Q93 [MBA] (Statistics) — Which of the following statements regarding p-values are TRUE? (Select all that apply.) A) A p-value <0.05 indicates that the null hypothesis is false B) The p-value is the probability of obtaining the observed results (or more extreme) if the null hypothesis is true C) A p-value of 0.01 means there is a 1% chance that the results are due to random variation D) The p-value does not indicate the clinical significance of a finding E) A p-value >0.05 proves that the null hypothesis is true
Answer: B, D The p-value is the probability of observing the data (or more extreme results) assuming the null hypothesis is true (B is correct). A small p-value suggests evidence against the null hypothesis but does not prove the alternative (A is false — the null is never "proven" or "disproven" by a single study). The p-value does not measure the probability that the results are due to chance (C is a common misinterpretation). P-values say nothing about clinical importance (D is correct). A non-significant P-value does not prove the null hypothesis (E is false — absence of evidence is not evidence of absence).
Q94 [SBA] (Statistics) — A randomised controlled trial compares misoprostol versus oxytocin for induction of labour. The primary outcome is vaginal delivery within 24 hours. Which statistical test is most appropriate to compare the proportions of women achieving this outcome between the two groups? A) Student's t-test B) Mann-Whitney U test C) Chi-squared (χ²) test D) Pearson correlation coefficient E) ANOVA
Answer: C A Chi-squared test (χ²) is used to compare proportions (categorical outcomes) between two independent groups. The outcome (vaginal delivery within 24 hours) is binary (yes/no), and the groups are independent (different women receive different treatments). Student's t-test (A) is for continuous normally distributed data. Mann-Whitney (B) is for non-parametric continuous data.
Q95 [SBA] (Statistics) — A Kaplan-Meier survival analysis is used to compare time to pregnancy in two groups of subfertile women (Group A: managed expectantly; Group B: underwent ovulation induction). Which of the following best describes a key assumption of the Kaplan-Meier method? A) The data must be normally distributed B) Censored observations are non-informative (i.e., independent of the event) C) All patients must have complete follow-up D) The hazard ratio is constant over time E) The two groups must have equal sample sizes
Answer: B A key assumption of Kaplan-Meier analysis is non-informative censoring — patients who are censored (lost to follow-up or have not yet achieved the event by study end) have the same prognosis as those who remain under follow-up. If censoring is related to the outcome (e.g., women with poor prognosis drop out), the estimates may be biased. Kaplan-Meier does not require normal distribution (A), complete follow-up (C), or equal sample sizes (E). Constant hazard ratio (D) is an assumption of Cox proportional hazards, not Kaplan-Meier.
Q96 [SBA] (Statistics) — A study reports a 95% confidence interval for the odds ratio (OR) of endometriosis associated with prolonged menstrual bleeding as 1.8 to 4.2. Which of the following is the correct interpretation? A) There is a 95% probability that the true OR lies between 1.8 and 4.2 B) If the study were repeated 100 times, 95 of the confidence intervals would contain the true OR C) The OR is statistically significant at the 5% level because the CI excludes 1.0 D) The p-value for this association is exactly 0.05 E) The association is clinically significant because the CI does not cross 1.0
Answer: C The 95% CI (1.8–4.2) does not include 1.0 (the null value for OR), indicating that the association is statistically significant at α = 0.05 (p < 0.05). The correct probabilistic interpretation is B (frequentist definition): 95% of CIs from repeated sampling would contain the true value. A is a common Bayesian misinterpretation. The CI does not give the p-value (D) or directly measure clinical significance (E).
Q97 [MBA] (Statistics) — Which of the following are recognised methods to reduce bias in randomised controlled trials? (Select all that apply.) A) Concealed allocation (concealment of randomisation sequence) B) Blinding of participants and outcome assessors C) Intention-to-treat analysis D) Post-hoc subgroup analysis E) Use of a placebo control
Answer: A, B, C, E Concealed allocation (A) prevents selection bias. Blinding (B) prevents performance and detection bias. Intention-to-treat analysis (C) prevents attrition bias and preserves the benefits of randomisation. Placebo control (E) reduces expectation bias. Post-hoc subgroup analysis (D) is a source of bias (multiple comparisons, data dredging) and not a method to reduce bias.
Q98 [SBA] (Statistics) — A screening test for cervical cancer has a specificity of 98%. Which of the following best describes the clinical consequence of a test with high specificity? A) Few false negatives — good for ruling out disease (SnNOut) B) Few false positives — good for ruling in disease (SpPIn) C) High sensitivity ensures low false positive rate D) High negative predictive value regardless of prevalence E) The test is suitable for screening asymptomatic populations
Answer: B High specificity (SpPIn = Specific test, Positive result rules IN disease) means there are few false positives. A positive result in a highly specific test is strongly suggestive of disease. However, specificity alone does not determine predictive value (D is false — PPV depends on prevalence). High sensitivity (SnNOut) is for ruling out disease (A).
Q99 [SBA] (Statistics) — A study investigates the association between body mass index (BMI) and the risk of gestational diabetes mellitus (GDM). The results show a Pearson correlation coefficient (r) of 0.65 between BMI and fasting glucose at 28 weeks. Which of the following is the correct interpretation? A) 65% of the variation in fasting glucose is explained by BMI B) There is a strong positive linear relationship between BMI and fasting glucose C) A BMI of 30 kg/m² causes a 65% increase in fasting glucose D) The coefficient of determination (R²) is 0.65 E) There is no significant correlation because r < 0.7
Answer: B A Pearson r of 0.65 indicates a strong positive linear correlation (generally interpreted as moderate-to-strong). The coefficient of determination R² = r² = 0.65² = 0.4225, meaning ~42% (not 65%) of the variance in fasting glucose is explained by BMI (A and D are wrong). Correlation does not imply causation (C is wrong — stating causation). An r of 0.65 can certainly be statistically significant depending on sample size (E is wrong).
Q100 [MBA] (Clinical/Surgical) — Which of the following are recognised contraindications to the use of the Mirena intrauterine system (levonorgestrel-releasing IUS) for contraception? (Select all that apply.) A) Current breast cancer B) Unexplained abnormal uterine bleeding C) History of pelvic inflammatory disease within the last 3 months D) Current copper allergy E) Cervical intraepithelial neoplasia (CIN)
Answer: A, B, C The UKMEC (UK Medical Eligibility Criteria) classifies current breast cancer (A) as UKMEC 4 (unacceptable risk — progestogen may stimulate tumour growth). Unexplained abnormal uterine bleeding (B) is UKMEC 2/3 until investigated to exclude endometrial pathology. Current PID or within 3 months (C) is UKMEC 4 — insertion should be deferred. Copper allergy (D) is a contraindication to copper-bearing IUDs, not the levonorgestrel IUS. CIN (E) is not a contraindication to IUS use (UKMEC 1).
Answer Key Summary
| Q | Type | Topic | Answer |
|---|---|---|---|
| 1 | SBA | Anatomy | B |
| 2 | SBA | Anatomy | B |
| 3 | SBA | Anatomy | C |
| 4 | MBA | Anatomy | A, B, C |
| 5 | SBA | Anatomy | D |
| 6 | SBA | Anatomy | D |
| 7 | SBA | Anatomy | B |
| 8 | MBA | Anatomy | B, C |
| 9 | SBA | Anatomy | B |
| 10 | SBA | Anatomy | D |
| 11 | SBA | Anatomy | A |
| 12 | MBA | Anatomy | C, D, E |
| 13 | SBA | Repro Phys | B |
| 14 | SBA | Repro Phys | B |
| 15 | SBA | Repro Phys | A |
| 16 | MBA | Repro Phys | A, B, C, E |
| 17 | SBA | Repro Phys | C |
| 18 | SBA | Repro Phys | C |
| 19 | SBA | Repro Phys | B |
| 20 | SBA | Repro Phys | B |
| 21 | MBA | Repro Phys | A, C, E |
| 22 | SBA | Endocrinology | B |
| 23 | SBA | Endocrinology | A |
| 24 | SBA | Endocrinology | A |
| 25 | MBA | Endocrinology | A, C, E |
| 26 | SBA | Endocrinology | B |
| 27 | SBA | Endocrinology | A |
| 28 | SBA | Endocrinology | B |
| 29 | MBA | Endocrinology | A, B, C, D, E |
| 30 | SBA | Fetal/Neonatal Phys | B |
| 31 | SBA | Fetal/Neonatal Phys | B |
| 32 | SBA | Fetal/Neonatal Phys | B |
| 33 | SBA | Fetal/Neonatal Phys | B |
| 34 | MBA | Fetal/Neonatal Phys | B, C, D |
| 35 | SBA | Fetal/Neonatal Phys | A |
| 36 | SBA | Fetal/Neonatal Phys | B |
| 37 | SBA | Fetal/Neonatal Phys | B |
| 38 | MBA | Clinical/Surgical | A, B, E |
| 39 | SBA | Pathology | B |
| 40 | SBA | Pathology | B |
| 41 | SBA | Pathology | B |
| 42 | SBA | Pathology | B |
| 43 | MBA | Clinical/Surgical | A, C, E |
| 44 | SBA | Pathology | B |
| 45 | SBA | Pathology | B |
| 46 | MBA | Pathology | A, D, E |
| 47 | SBA | Pathology | B |
| 48 | SBA | Pathology | C |
| 49 | SBA | Pathology | B |
| 50 | SBA | Pharmacology | A |
| 51 | MBA | Pharmacology | A, C |
| 52 | SBA | Pharmacology | B |
| 53 | SBA | Pharmacology | B |
| 54 | SBA | Pharmacology | C |
| 55 | SBA | Pharmacology | B |
| 56 | MBA | Clinical/Surgical | B, D, E |
| 57 | SBA | Pharmacology | B |
| 58 | SBA | Pharmacology | B |
| 59 | MBA | Pharmacology | A, B, C, E |
| 60 | SBA | Pharmacology | B |
| 61 | SBA | Microbiology | B |
| 62 | SBA | Microbiology | B |
| 63 | SBA | Microbiology | C |
| 64 | SBA | Microbiology | C |
| 65 | MBA | Microbiology | A, B, D |
| 66 | SBA | Microbiology | C |
| 67 | SBA | Microbiology | B |
| 68 | MBA | Microbiology | A, B, D |
| 69 | SBA | Immunology | C |
| 70 | SBA | Immunology | B |
| 71 | SBA | Immunology | A |
| 72 | MBA | Immunology | A, B, C, D |
| 73 | SBA | Immunology | A |
| 74 | SBA | Repro Phys | D |
| 75 | SBA | Biochemistry | A |
| 76 | SBA | Biochemistry | A |
| 77 | MBA | Biochemistry | A, B, D |
| 78 | SBA | Biochemistry | A |
| 79 | SBA | Biochemistry | A |
| 80 | MBA | Genetics | A, B, C |
| 81 | SBA | Genetics | B |
| 82 | SBA | Genetics | B |
| 83 | SBA | Genetics | C |
| 84 | MBA | Genetics | A, B, C, D |
| 85 | SBA | Embryology | C |
| 86 | SBA | Embryology | B |
| 87 | SBA | Embryology | A |
| 88 | SBA | Embryology | C |
| 89 | MBA | Statistics | A, B, D, E |
| 90 | SBA | Embryology | B |
| 91 | SBA | Statistics | C |
| 92 | SBA | Statistics | B |
| 93 | MBA | Statistics | B, D |
| 94 | SBA | Statistics | C |
| 95 | SBA | Statistics | B |
| 96 | SBA | Statistics | C |
| 97 | MBA | Statistics | A, B, C, E |
| 98 | SBA | Statistics | B |
| 99 | SBA | Statistics | B |
| 100 | MBA | Clinical/Surgical | A, B, C |
MRCOG Part 1 — Mock Exam 3b
Full Simulation — Second Half (100 Questions)
Instructions: Each question is either SBA (Single Best Answer — select one correct option) or MBA (Multiple Best Answer — select all correct options). Mark your answers accordingly.
Q101 [SBA] (Anatomy) — A 34-year-old woman undergoes laparoscopic excision of a left ovarian dermoid cyst. During mobilisation of the ovary, the surgeon identifies the suspensory ligament of the ovary (infundibulopelvic ligament). Which of the following structures is NOT contained within the suspensory ligament of the ovary? A) Ovarian artery B) Ovarian vein C) Ovarian nerve plexus D) Pampiniform plexus of veins E) Lymphatic vessels draining the ovary
Answer: D The suspensory ligament of the ovary (infundibulopelvic ligament) contains the ovarian artery, vein, nerve plexus, and lymphatic vessels. The pampiniform plexus of veins is found within the broad ligament near the ovary and fallopian tube, not specifically within the suspensory ligament. The ovarian lymphatics drain to the para-aortic lymph nodes, not the pelvic nodes.
Q102 [SBA] (Anatomy) — A 40-year-old woman undergoes a sacrospinous ligament fixation for vaginal vault prolapse. The surgeon places sutures through the sacrospinous ligament approximately 2 cm medial to the ischial spine. Which nerve is at greatest risk of injury with this approach? A) Sciatic nerve B) Pudendal nerve C) Inferior gluteal nerve D) Posterior femoral cutaneous nerve E) Obturator nerve
Answer: B The pudendal nerve runs posterior to the sacrospinous ligament near its attachment to the ischial spine. When sutures are placed through the sacrospinous ligament, the pudendal nerve is at risk, particularly if sutures are placed too far laterally. The sciatic nerve lies posterior to the piriformis and is less at risk. The posterior femoral cutaneous nerve runs with the sciatic nerve.
Q103 [MBA] (Anatomy) — Which of the following structures form the boundaries of the pelvic inlet (superior pelvic strait)? (Select all that apply.) A) Sacral promontory B) Iliopectineal (arcuate) line C) Ischial spine D) Pubic symphysis (superior border) E) Sacrotuberous ligament
Answer: A, B, D The pelvic inlet is bounded posteriorly by the sacral promontory, laterally by the iliopectineal (arcuate) line on each side, and anteriorly by the pubic symphysis (superior border). The ischial spine (C) is a landmark of the mid-pelvis, not the inlet. The sacrotuberous ligament (E) is part of the pelvic outlet boundary.
Q104 [SBA] (Anatomy) — During a caesarean section, the surgeon extends the uterine incision laterally and encounters brisk bleeding. The bleeding is from the uterine artery. At the level of the uterine isthmus, the uterine artery runs in relation to the ureter. Which of the following best describes this relationship? A) The uterine artery runs medial to the ureter B) The uterine artery crosses superior to the ureter approximately 2 cm lateral to the cervix C) The uterine artery runs inferior to the ureter D) The uterine artery crosses the ureter at the level of the pelvic brim E) The ureter pierces the uterine artery at the level of the internal os
Answer: B The uterine artery arises from the anterior division of the internal iliac artery and courses medially towards the uterus. It crosses superior to the ureter approximately 2 cm lateral to the cervix — the classic "water under the bridge" relationship. This is the most critical anatomical relationship during hysterectomy and caesarean section extension.
Q105 [SBA] (Anatomy) — A 32-year-old woman undergoes a laparoscopic tubal ligation. The surgeon identifies the fallopian tube within the broad ligament. Which of the following best describes the anatomical divisions of the fallopian tube from lateral to medial? A) Isthmus, ampulla, infundibulum, interstitial B) Infundibulum, ampulla, isthmus, interstitial (intramural) C) Ampulla, infundibulum, interstitial, isthmus D) Interstitial, isthmus, ampulla, infundibulum E) Fimbriae, ampulla, interstitial, isthmus
Answer: B The fallopian tube is divided into four parts from lateral to medial: infundibulum (with fimbriae), ampulla (the widest and longest segment, where fertilisation typically occurs), isthmus (narrow, thick-walled segment), and interstitial (intramural) portion that traverses the uterine wall.
Q106 [MBA] (Anatomy) — Which of the following statements about the blood supply of the female genital tract are correct? (Select all that apply.) A) The ovarian artery anastomoses with the tubal branch of the uterine artery B) The vaginal artery is typically a branch of the internal iliac artery (anterior division) C) The uterine artery gives off a cervicovaginal branch before ascending along the uterus D) The artery of the round ligament arises from the superior epigastric artery E) The middle rectal artery supplies the upper vagina
Answer: A, B, C The ovarian artery anastomoses with the tubal branch of the uterine artery along the mesosalpinx (A is correct). The vaginal artery is usually a branch of the anterior division of the internal iliac artery (B is correct). The uterine artery gives off a cervicovaginal branch at the level of the cervix (C is correct). The artery of the round ligament (Sampson's artery) arises from the inferior epigastric artery, not the superior epigastric (D is false). The middle rectal artery supplies the rectum, not the upper vagina — the vaginal artery and uterine artery branches supply the vagina (E is false).
Q107 [SBA] (Anatomy) — A 29-year-old woman presents with a painless groin swelling. On examination, the swelling is above the inguinal ligament and medial to the pubic tubercle. It reduces with pressure. Which of the following best describes the boundaries of the inguinal canal through which this hernia passes? A) Anterior wall: external oblique aponeurosis; posterior wall: internal oblique aponeurosis B) Anterior wall: external oblique aponeurosis; posterior wall: transversalis fascia C) Roof: inguinal ligament; floor: conjoint tendon D) Anterior wall: transversus abdominis; posterior wall: external oblique E) Roof: lacunar ligament; floor: external oblique
Answer: B The inguinal canal has four walls: anterior (external oblique aponeurosis reinforced laterally by internal oblique), posterior (transversalis fascia reinforced medially by the conjoint tendon), roof (internal oblique and transversus abdominis arching fibres), and floor (inguinal ligament and lacunar ligament). This describes a direct inguinal hernia, which is above the inguinal ligament and medial to the pubic tubercle.
Q108 [SBA] (Anatomy) — A 45-year-old woman undergoes a radical hysterectomy for cervical cancer. During the procedure, the surgeon must identify and preserve the pelvic autonomic nerves. Which of the following best describes the course of the pelvic splanchnic nerves (nervi erigentes)? A) They arise from the lumbar sympathetic chain and join the inferior hypogastric plexus B) They arise from the sacral nerve roots S2–S4 and carry parasympathetic fibres to the pelvic viscera C) They are branches of the pudendal nerve that supply sensory fibres to the pelvic floor D) They arise from the aortic plexus and descend along the common iliac vessels E) They run within the uterosacral ligaments and supply sympathetic innervation to the bladder
Answer: B The pelvic splanchnic nerves (nervi erigentes) arise from the anterior rami of S2–S4 sacral nerve roots. They carry preganglionic parasympathetic fibres that synapse in the pelvic (inferior hypogastric) plexus. These fibres are critical for bladder emptying (detrusor contraction), penile erection, and rectal function. They are distinct from the sympathetic hypogastric nerves.
Q109 [SBA] (Anatomy) — A 36-year-old woman undergoes a vulval biopsy for a suspicious pigmented lesion. The biopsy site is on the labium majus. Which nerve provides sensory innervation to the anterior portion of the labium majus? A) Pudendal nerve (perineal branch) B) Ilioinguinal nerve C) Genitofemoral nerve (genital branch) D) Posterior femoral cutaneous nerve (perineal branch) E) Obturator nerve
Answer: C The genital branch of the genitofemoral nerve (L1–L2) supplies the anterior part of the labium majus and the mons pubis. The ilioinguinal nerve (B) supplies the medial upper thigh and root of the penis/labium majus but has a smaller anterior contribution. The pudendal nerve (A) supplies the posterior labium majus and perineum. The posterior femoral cutaneous nerve (D) supplies the posterior aspect of the labium majus.
Q110 [SBA] (Anatomy) — During a vaginal hysterectomy, the surgeon places clamps on the cardinal ligaments (Mackenrodt's ligaments). Which of the following best describes the anatomical content of the cardinal ligament? A) Ovarian vessels and suspensory ligament B) Uterine artery, uterine veins, and ureter C) Uterine artery, uterine veins, and cervical branches of the pelvic plexus D) Round ligament and ovarian ligament E) Transverse cervical ligament containing only connective tissue
Answer: C The cardinal ligaments (transverse cervical ligaments or Mackenrodt's ligaments) extend from the cervix and upper vagina to the lateral pelvic walls. They contain the uterine artery and veins, cervical branches of the pelvic autonomic plexus, lymphatic vessels, and dense connective tissue. The ureter passes through the cardinal ligament in its course to the bladder, approximately 1.5–2 cm lateral to the cervix.
Q111 [MBA] (Anatomy) — Which of the following structures drain lymph directly into the para-aortic (lumbar) lymph nodes? (Select all that apply.) A) Ovary B) Fundus of the uterus C) Upper third of the vagina D) Cervix E) Vulva
Answer: A, B The ovaries (A) and fundus of the uterus (B) drain lymph via the ovarian and broad ligament lymphatics directly to the para-aortic (lumbar) lymph nodes at the level of L1–L2. The cervix (D) drains primarily to the internal and external iliac and obturator nodes. The upper third of the vagina (C) drains to the iliac nodes, while the lower two-thirds drain to the inguinal nodes. The vulva (E) drains to the superficial inguinal nodes.
Q112 [SBA] (Anatomy) — A 38-year-old woman with stage IB cervical cancer undergoes a radical hysterectomy (Wertheim's procedure). The surgeon dissects the ureter from its attachment to the peritoneum and identifies its entry point into the bladder. At what point does the ureter enter the bladder wall? A) At the level of the internal cervical os B) At the trigone of the bladder, approximately 2 cm from the midline C) At the vesicoureteric junction, passing obliquely through the detrusor muscle D) At the bladder dome, entering superiorly E) At the junction of the bladder base and urethra
Answer: C The ureter enters the bladder wall at the vesicoureteric junction after a short intramural course of approximately 1.5–2 cm. It passes obliquely through the detrusor muscle, which creates a one-way valve mechanism that prevents vesicoureteric reflux. The ureter enters the bladder at the lateral angle of the trigone, approximately 2 cm from the midline and 2–3 cm above the internal urethral meatus.
Q113 [SBA] (Anatomy) — A 42-year-old woman with stress urinary incontinence undergoes a mid-urethral sling procedure (retropubic approach). The surgeon passes trocars through the retropubic space (space of Retzius). Which of the following vessels is most at risk of injury during blind passage of trocars through this space? A) Obturator artery B) Inferior epigastric artery C) External iliac artery D) Internal pudendal artery E) Dorsal artery of the clitoris
Answer: B The inferior epigastric artery (a branch of the external iliac artery) runs along the posterior surface of the rectus abdominis muscle and is the most frequently injured vessel during retropubic mid-urethral sling procedures. The obturator artery is at risk during the transobturator approach but less so during the retropubic approach. The external iliac vessels lie more laterally and are protected by the psoas muscle.
Q114 [SBA] (Reproductive Physiology) — A 33-year-old woman with regular 28-day cycles undergoes a day 21 progesterone test that confirms ovulation. On day 22 of her cycle, she has a sudden onset of lower abdominal pain and vaginal spotting. Transvaginal ultrasound shows a 3 cm corpus luteum cyst with internal echoes. Which of the following best describes the hormonal changes that occur immediately after luteinisation of the granulosa cells? A) Aromatase activity increases, converting androstenedione to oestradiol B) Theca interna cells begin producing progesterone instead of androstenedione C) Both granulosa and theca cells undergo luteinisation and produce progesterone D) LH receptor expression on granulosa cells is downregulated by progesterone E) Progesterone suppresses granulosa cell apoptosis through Bcl-2 upregulation
Answer: C After ovulation, both granulosa and theca interna cells undergo luteinisation (morphological transformation to luteal cells). The granulosa-derived luteal cells (large luteal cells) produce progesterone and oestradiol, while the theca-derived luteal cells (small luteal cells) produce primarily androstenedione and progesterone. This dual origin of the corpus luteum is essential for adequate progestogen production.
Q115 [SBA] (Reproductive Physiology) — A 27-year-old woman with hypogonadotrophic hypogonadism is undergoing ovulation induction with pulsatile GnRH therapy. Which of the following best describes the physiological rationale for using pulsatile (rather than continuous) GnRH administration? A) Pulsatile GnRH stimulates FSH secretion only, avoiding LH surge B) Continuous GnRH downregulates pituitary GnRH receptors, suppressing gonadotrophin release C) Pulsatile GnRH is required for oocyte maturation but not follicular growth D) Continuous GnRH preferentially stimulates LH over FSH E) Pulsatile GnRH directly stimulates ovarian follicular development without pituitary involvement
Answer: B The physiological basis of pulsatile GnRH therapy is that continuous GnRH administration causes desensitisation and downregulation of pituitary GnRH receptors, paradoxically suppressing gonadotrophins (the basis of GnRH agonist therapy). Pulsatile GnRH at physiological frequencies (approximately one pulse every 60–90 minutes) maintains pituitary responsiveness and stimulates appropriate LH and FSH secretion.
Q116 [MBA] (Reproductive Physiology) — Which of the following are established functions of inhibin B in female reproductive physiology? (Select all that apply.) A) Selective suppression of FSH secretion from the pituitary B) Promotion of early follicular recruitment C) Inhibition of activin signalling in the pituitary D) Stimulation of LH secretion from gonadotrophs E) Paracrine regulation of theca cell androgen production
Answer: A, B, C Inhibin B, produced primarily by granulosa cells of small antral follicles, selectively suppresses FSH secretion (A) by inhibiting activin-stimulated FSH production in the pituitary (C). In the early follicular phase, declining inhibin B (and falling oestradiol) allows FSH to rise, promoting follicular recruitment (B). Inhibin B does not stimulate LH secretion (D). Theca cell regulation is primarily by LH and local paracrine factors (E).
Q117 [SBA] (Reproductive Physiology) — A 31-year-old woman undergoes controlled ovarian hyperstimulation for IVF. On the day of hCG trigger, her serum oestradiol is 5500 pmol/L and she has 18 follicles >14 mm. Which of the following best explains why hCG (rather than LH) is used to trigger final oocyte maturation? A) hCG has a longer half-life than LH, sustaining the signal for final maturation B) hCG has a higher affinity for the FSH receptor than LH C) hCG directly stimulates granulosa cell proliferation better than LH D) LH cannot bind to the LH/CG receptor on the corpus luteum E) hCG avoids the risk of ovarian hyperstimulation syndrome
Answer: A Human chorionic gonadotrophin (hCG) is used for the final trigger because it has a much longer half-life (~24–36 hours) compared to LH (~20–30 minutes). Both bind to the same LH/CG receptor, but the sustained action of hCG provides a prolonged signal that is necessary to complete oocyte meiotic maturation, luteinisation, and cumulus expansion. The long half-life of hCG is also the reason it increases OHSS risk (E is false).
Q118 [SBA] (Reproductive Physiology) — A 36-year-old woman with regular menstrual cycles is trying to conceive. She asks about the optimal timing for intercourse. Which of the following best describes the fertile window duration in natural conception? A) 24 hours before ovulation to 12 hours after ovulation B) 48 hours before ovulation to 24 hours after ovulation C) Approximately 6 days, ending on the day of ovulation D) 3 days before ovulation to 3 days after ovulation E) Only the day of ovulation itself
Answer: C The fertile window is approximately 6 days — ending on the day of ovulation. Sperm can survive in the female reproductive tract for up to 5 days, while the oocyte remains fertilisable for approximately 12–24 hours after ovulation. The highest probability of conception occurs when intercourse takes place in the 2–3 days before ovulation. The window is determined by the lifespan of sperm and the oocyte.
Q119 [MBA] (Reproductive Physiology) — Which of the following statements regarding the maternal physiological adaptation to pregnancy are correct? (Select all that apply.) A) Cardiac output increases by approximately 40% by the end of the second trimester B) Systemic vascular resistance decreases, leading to a physiological fall in blood pressure in mid-pregnancy C) Tidal volume remains unchanged, while respiratory rate increases D) Glomerular filtration rate (GFR) increases by approximately 50% E) Plasma volume increases proportionally more than red cell mass, causing a physiological anaemia
Answer: A, B, D, E Cardiac output increases 30–50% by 24–28 weeks (A). Systemic vascular resistance falls due to oestrogen-mediated vasodilation and the low-resistance placental circulation, causing a mid-trimester BP nadir (B). GFR increases by ~50% (D). Plasma volume increases ~40–50%, while red cell mass increases ~20–30%, creating a dilutional (physiological) anaemia (E). Tidal volume INCREASES significantly in pregnancy (not unchanged — C is false), while respiratory rate is minimally changed.
Q120 [SBA] (Reproductive Physiology) — A 29-year-old woman who is exclusively breastfeeding presents with amenorrhoea at 6 months postpartum. She has not yet resumed menstruation. Which of the following best describes the mechanism of lactational amenorrhoea? A) Prolactin directly inhibits ovarian oestradiol production B) Suckling-induced hyperprolactinaemia suppresses GnRH pulsatility C) Oxytocin from breastfeeding inhibits LH secretion from the pituitary D) High progesterone levels from the persistent corpus luteum suppress FSH E) Prolactin downregulates FSH receptors on granulosa cells
Answer: B Lactational amenorrhoea is primarily due to suckling-induced hyperprolactinaemia, which suppresses hypothalamic GnRH pulse frequency. Low-frequency GnRH pulses favour FSH secretion but are insufficient to maintain the LH pulsatility needed for follicular development and ovulation. Prolactin itself does not directly inhibit ovarian function (A and E are incorrect). The corpus luteum regresses if pregnancy does not occur (D).
Q121 [SBA] (Reproductive Physiology) — A 34-year-old woman has a serum anti-Müllerian hormone (AMH) level of 1.2 pmol/L (low for her age). Which of the following best describes the relationship between AMH and the early follicular phase FSH level? A) AMH potentiates FSH action on granulosa cells, promoting follicular growth B) AMH inhibits FSH-stimulated granulosa cell proliferation and follicular recruitment C) AMH and FSH have a direct synergistic effect on theca cell androgen production D) AMH increases the sensitivity of the pituitary to GnRH, suppressing FSH release E) AMH is secreted in response to rising FSH levels and feeds back to increase FSH
Answer: B Anti-Müllerian hormone (AMH) inhibits the sensitivity of small pre-antral and antral follicles to FSH, thereby controlling the rate of follicular recruitment. As AMH levels decline with age and diminishing ovarian reserve, the inhibitory brake on FSH-mediated follicular growth is released, leading to an earlier rise in FSH and accelerated follicle recruitment. This explains the inverse relationship between AMH and early follicular FSH levels.
Q122 [SBA] (Reproductive Physiology) — A 37-year-old woman presents with secondary infertility. She has regular 26-day cycles. A day 21 progesterone is 45 nmol/L. Which of the following statements about the luteal phase in normal conception cycles is correct? A) The luteal phase is of fixed duration (14 ± 2 days) regardless of cycle length B) Luteal phase progesterone peaks on the day of implantation C) The luteal phase varies proportionally with follicular phase length D) Progesterone levels <30 nmol/L definitively indicate anovulation E) The luteal phase can be reliably extended by exogenous oestrogen
Answer: A The luteal phase is remarkably constant in duration (14 ± 2 days) irrespective of total cycle length. Cycle variability is almost entirely due to differences in the follicular phase. Luteolysis is triggered by falling LH levels and prostaglandin-mediated mechanisms, not by the absence of implantation. The corpus luteum lifespan is fixed at ~12–14 days unless rescued by hCG from an implanting embryo.
Q123 [MBA] (Reproductive Physiology) — Which of the following are known effects of oestradiol on the female reproductive tract during the follicular phase? (Select all that apply.) A) Proliferation of the endometrial glands and stroma B) Increased contractility of the fallopian tube smooth muscle C) Thinning and increased alkalinity of cervical mucus D) Increased myometrial contractility and spontaneous activity E) Inhibition of endometrial prostaglandin synthesis
Answer: A, B, C, D Oestradiol promotes endometrial proliferation (A), increases tubal ciliary activity and smooth muscle contractility (B), produces thin, watery, alkaline cervical mucus (C), and increases myometrial contractility (D). Oestradiol does NOT inhibit endometrial prostaglandin synthesis — in fact, it upregulates prostaglandin synthesis enzymes. Progesterone has an inhibitory effect on prostaglandins (E is false).
Q124 [SBA] (Endocrinology) — A 29-year-old woman with known hypopituitarism (secondary hypothyroidism and secondary adrenal insufficiency) is planning pregnancy. She is on levothyroxine 100 μg daily and hydrocortisone 20 mg daily. Which of the following is the most important endocrine consideration during labour and delivery in this patient? A) Levothyroxine dose should be doubled during labour B) Stress-dose hydrocortisone (50–100 mg intravenously) is required during active labour C) Hydrocortisone is contraindicated during labour due to impaired wound healing D) She is at increased risk of postpartum thyroiditis E) She should receive ephedrine as first-line vasopressor for hypotension
Answer: B Patients with secondary adrenal insufficiency cannot mount an adequate cortisol response to the physiological stress of labour. Stress-dose glucocorticoid cover (e.g., hydrocortisone 50–100 mg IV 6–8 hourly) is essential during labour and the immediate postpartum period to prevent adrenal crisis. Levothyroxine does not require acute adjustment during labour (A is unnecessary). Thyroid dosing may need postpartum adjustment but not acutely during delivery.
Q125 [SBA] (Endocrinology) — A 33-year-old woman presents with heat intolerance, weight loss, and palpitations at 16 weeks gestation. Her TSH is <0.01 mIU/L and free T4 is 32 pmol/L (normal non-pregnant: 9–24 pmol/L). Which of the following best distinguishes gestational transient thyrotoxicosis from Graves' disease in pregnancy? A) Free T4 is higher in gestational thyrotoxicosis than in Graves' disease B) TSH receptor antibody (TRAb) is elevated in Graves' disease but not in gestational thyrotoxicosis C) Gestational thyrotoxicosis is associated with positive anti-thyroid peroxidase antibodies D) Graves' disease typically resolves spontaneously by 20 weeks gestation E) The presence of a goitre differentiates Graves' disease from gestational thyrotoxicosis
Answer: B Gestational transient thyrotoxicosis (GTT) is caused by the weak thyrotrophic activity of high hCG levels, typically in the first trimester, and resolves spontaneously. TSH receptor antibodies (TRAb) are elevated in Graves' disease but not in GTT — this is the best distinguishing feature. GTT is associated with hyperemesis gravidarum and does not cause a goitre or ophthalmopathy. Anti-TPO antibodies (C) are not specific to either condition.
Q126 [MBA] (Endocrinology) — Which of the following clinical features are associated with Cushing's syndrome in women of reproductive age? (Select all that apply.) A) Osteoporosis and pathological fractures B) Hirsutism and acne C) Oligomenorrhoea or amenorrhoea D) Hypoglycaemia due to increased insulin sensitivity E) Purple striae on the abdomen and proximal myopathy
Answer: A, B, C, E Cushing's syndrome (chronic glucocorticoid excess) causes osteoporosis (A), hirsutism and acne due to adrenal androgen co-secretion (B), and menstrual disturbances through suppression of GnRH and gonadotrophins (C). Purple striae (≥1 cm width) and proximal myopathy (E) are specific clinical signs. Cushing's causes HYPERglycaemia (impaired glucose tolerance or diabetes), not hypoglycaemia (D is false — glucocorticoids are insulin-antagonistic).
Q127 [SBA] (Endocrinology) — A 26-year-old woman with type 1 diabetes mellitus is planning pregnancy. She is on a continuous subcutaneous insulin infusion (CSII) pump. Her HbA1c is 55 mmol/mol (7.2%). Which of the following best describes the impact of pregnancy on insulin pharmacokinetics? A) Insulin requirements decrease progressively throughout pregnancy due to fetal glucose utilisation B) First-trimester insulin requirements increase sharply due to rising hCG levels C) Insulin resistance increases most significantly in the third trimester, particularly between 26–34 weeks D) Subcutaneous insulin absorption is enhanced in pregnancy due to increased peripheral blood flow E) Insulin degludec (ultra-long acting) is recommended as first-line due to its stable pharmacokinetic profile
Answer: C Pregnancy induces progressive insulin resistance driven primarily by human placental lactogen (hPL), cortisol, and other hormones. This is most pronounced in the third trimester (26–34 weeks), when insulin requirements may increase by 50–100% or more compared to pre-pregnancy doses. In the first trimester, some women experience increased hypoglycaemia due to nausea and reduced intake (B is false). Insulin degludec (E) lacks sufficient safety data in pregnancy and is not recommended by current guidelines.
Q128 [SBA] (Endocrinology) — A 42-year-old perimenopausal woman presents with hot flushes, night sweats, and sleep disturbance. Her serum FSH is 35 IU/L, and oestradiol is 95 pmol/L. She has an intact uterus. She is considering menopausal hormone therapy (MHT). Which of the following best describes the endocrinology of the menopausal transition? A) Oestradiol levels decline abruptly at menopause due to complete loss of ovarian follicles B) Inhibin B levels rise as a compensatory mechanism to suppress FSH C) The initial hormonal change is a rise in FSH due to declining inhibin B levels D) Anti-Müllerian hormone levels increase transiently during perimenopause E) Testosterone production from the ovary ceases completely at menopause
Answer: C The earliest hormonal change of the menopausal transition is a rise in FSH, driven by declining inhibin B levels (produced by small antral follicles). This occurs while oestradiol levels may still be normal or even elevated during the early perimenopause. Oestradiol decline is gradual, not abrupt (A is false). AMH declines progressively (D is false). The postmenopausal ovary continues to produce androgens (androstenedione and testosterone) from stromal cells (E is false).
Q129 [SBA] (Endocrinology) — A 30-year-old woman presents with secondary amenorrhoea for 8 months. She exercises 7 days per week and has a BMI of 17.8 kg/m². Her FSH is 3.2 IU/L, LH is 2.1 IU/L, and oestradiol is 60 pmol/L. Prolactin and TSH are normal. Which of the following best describes the neuroendocrine mechanism of functional hypothalamic amenorrhoea (FHA)? A) Excess cortisol suppresses GnRH pulse generator activity B) Reduced leptin levels suppress kisspeptin signalling in the hypothalamus C) Increased dopaminergic tone directly inhibits GnRH secretion D) Elevated β-endorphin levels block pituitary LH receptors E) Ghrelin deficiency impairs GnRH synthesis
Answer: B In FHA (hypothalamic amenorrhoea due to energy deficit/exercise), low body fat and energy availability reduce leptin secretion. Leptin acts on kisspeptin neurons in the arcuate nucleus and anteroventral periventricular nucleus of the hypothalamus, which are key regulators of GnRH secretion. Low leptin reduces kisspeptin signalling, leading to suppressed GnRH pulsatility and hypogonadotrophic hypogonadism. Cortisol may be elevated (A) but is not the primary mechanism — leptin-kisspeptin is the core pathway.
Q130 [MBA] (Endocrinology) — Which of the following hormones show significant diurnal (circadian) variation in their secretion? (Select all that apply.) A) Cortisol B) Growth hormone (GH) C) Prolactin D) Thyroxine (T4) E) Melatonin
Answer: A, B, C, E Cortisol (A) peaks in the early morning (6–8 AM) and nadirs around midnight. Growth hormone (B) is secreted in pulses predominantly during slow-wave sleep. Prolactin (C) peaks during sleep (particularly REM sleep). Melatonin (E) is secreted by the pineal gland at night and suppressed by light. Thyroxine (D) has minimal diurnal variation and remains relatively stable throughout the day.
Q131 [SBA] (Endocrinology) — A 24-year-old woman with primary amenorrhoea is found to have 46,XY karyotype with complete androgen insensitivity syndrome (CAIS). Which of the following best describes the endocrinology of this condition? A) The testes produce no testosterone due to Leydig cell agenesis B) Testosterone is produced but target tissues are resistant due to androgen receptor mutation C) Müllerian inhibiting substance (AMH) is absent, allowing uterine development D) Elevated LH levels suppress adrenal androgen production E) Oestrogen levels are undetectable due to lack of aromatase activity
Answer: B In CAIS, the testes produce normal testosterone and AMH, but androgen receptors are non-functional due to an X-linked AR gene mutation. Target tissues (including external genitalia) are resistant to androgens, leading to female external phenotype. AMH acts normally to regress Müllerian structures (C is false — the uterus is absent). Testosterone is aromatised to oestradiol peripherally, causing breast development at puberty. LH is elevated due to lack of androgen negative feedback.
Q132 [SBA] (Fetal/Neonatal) — A 26-week preterm infant is delivered by emergency caesarean section for fetal distress. At delivery, the infant has Apgar scores of 3 at 1 minute and 6 at 5 minutes. Cord blood gases show pH 7.12, base excess −10 mmol/L, and lactate 7.5 mmol/L. Which of the following best describes the fetal metabolic response to acute hypoxia? A) Increased oxidative phosphorylation in myocardial mitochondria B) Anaerobic glycolysis producing lactate with subsequent metabolic acidosis C) Ketone body production from fatty acid mobilisation D) Activation of the urea cycle to buffer hydrogen ions E) Increased gluconeogenesis from amino acids in the fetal liver
Answer: B In acute fetal hypoxia, the fetus shifts to anaerobic glycolysis in peripheral tissues, producing lactate as the end product. Lactate accumulation causes metabolic acidosis (low pH, low base excess, high lactate). The fetal myocardium can use lactate as a fuel source but relies primarily on glycolysis and glucose oxidation. The elevated cord blood lactate with base deficit confirms the metabolic (not respiratory) nature of the acidosis.
Q133 [SBA] (Fetal/Neonatal) — A 38-week gestation fetus is found to have a single umbilical artery (SUA) on ultrasound. Which of the following is the most significant associated clinical implication? A) SUA is a normal variant with no clinical significance B) SUA is associated with an increased risk of fetal aneuploidy and congenital malformations C) SUA always indicates the presence of velamentous cord insertion D) SUA requires urgent delivery due to risk of cord accident E) SUA only affects the venous system and has no arterial implications
Answer: B Single umbilical artery (SUA) is found in approximately 0.5–1% of pregnancies and is associated with an increased risk of fetal aneuploidy (particularly trisomy 13 and 18), congenital heart defects, renal anomalies, and intrauterine growth restriction. When isolated (no other anomalies), the prognosis is generally favourable, but detailed fetal anatomy scan and echocardiography are recommended. It does not typically require urgent delivery (D).
Q134 [MBA] (Fetal/Neonatal) — Which of the following physiological changes normally occur in the transition from fetal to neonatal circulation at birth? (Select all that apply.) A) Functional closure of the ductus arteriosus within the first 24–48 hours B) Rapid decrease in pulmonary vascular resistance with the first breaths C) Increase in left atrial pressure exceeding right atrial pressure, closing the foramen ovale D) Closure of the ductus venosus within minutes of cord clamping E) Immediate anatomical closure of the foramen ovale within the first hour
Answer: A, B, C At birth, the first breaths expand the lungs, dramatically decreasing pulmonary vascular resistance (B). Increased pulmonary blood flow returns to the left atrium, raising left atrial pressure above right atrial pressure, functionally closing the foramen ovale (C) — anatomical closure occurs over weeks to months (E is false). The ductus arteriosus constricts in response to rising arterial PO₂, with functional closure within 24–48 hours (A). The ductus venosus closes functionally within minutes to hours after cord clamping (D — "within minutes" is debateable; functional closure occurs over hours).
Q135 [SBA] (Fetal/Neonatal) — A term neonate develops hypoglycaemia (blood glucose 1.8 mmol/L) at 2 hours of life. The mother had well-controlled gestational diabetes mellitus (GDM). Which of the following best describes the pathophysiology of neonatal hypoglycaemia in infants of diabetic mothers? A) Maternal hyperglycaemia causes fetal pancreatic β-cell hyperplasia and subsequent hyperinsulinism B) Placental insufficiency limits glucose transfer to the fetus C) The neonate has impaired glycogenolysis due to immature hepatic enzymes D) Increased fetal catecholamines suppress neonatal gluconeogenesis E) Maternal insulin crosses the placenta and directly suppresses neonatal glucose production
Answer: A Poorly controlled maternal diabetes causes fetal hyperglycaemia, which stimulates fetal pancreatic β-cell hyperplasia and increased insulin secretion. After birth, the continuous supply of glucose via the placenta is abruptly interrupted, but the neonate's hyperinsulinaemic state persists, causing rapid glucose utilisation and hypoglycaemia. Maternal insulin does not cross the placenta in significant amounts (E is false). This typically occurs 1–3 hours after birth.
Q136 [SBA] (Fetal/Neonatal) — A 28-week gestation neonate develops respiratory distress syndrome (RDS). Surfactant replacement therapy is administered. Which of the following is the primary phospholipid component of pulmonary surfactant that reduces surface tension? A) Phosphatidylinositol B) Phosphatidylglycerol C) Dipalmitoylphosphatidylcholine (DPPC) D) Sphingomyelin E) Lecithin (phosphatidylcholine) — unsaturated form
Answer: C Dipalmitoylphosphatidylcholine (DPPC), a saturated phosphatidylcholine, is the primary surface tension-reducing phospholipid in surfactant. Its saturated fatty acid tails allow tight packing at the air-liquid interface, reducing surface tension to near-zero levels during expiration, preventing alveolar collapse. Unsaturated forms (E) cannot pack as tightly. The lecithin:sphingomyelin (L:S) ratio has been used historically to assess fetal lung maturity.
Q137 [MBA] (Fetal/Neonatal) — Which of the following biochemical markers measured in amniotic fluid or maternal serum are used to assess fetal lung maturity? (Select all that apply.) A) Lecithin/sphingomyelin (L/S) ratio B) Phosphatidylglycerol (PG) C) Lamellar body count D) Surfactant protein A (SP-A) E) Amniotic fluid cortisol
Answer: A, B, C The L/S ratio (≥2.0 indicates maturity — A), presence of phosphatidylglycerol (B), and lamellar body count (≥50,000/μL — C) are established tests for fetal lung maturity. Surfactant protein A (D) is a component of surfactant but is not routinely measured clinically for maturity assessment. Amniotic fluid cortisol (E) is not used clinically for lung maturity assessment.
Q138 [SBA] (Fetal/Neonatal) — A 35-week preterm infant develops apnoea and bradycardia episodes. Which of the following best describes the physiological basis for the increased risk of apnoea of prematurity? A) Mature peripheral chemoreceptor sensitivity to hypoxia B) Immature brainstem respiratory centres with exaggerated inhibitory responses to laryngeal stimulation C) Excess surfactant production causing alveolar over-distension D) Increased diaphragmatic muscle endurance compared to term infants E) Overactive Hering-Breuer reflex promoting sustained apnoea
Answer: B Apnoea of prematurity results from immature brainstem respiratory centre development, where inhibitory signals (particularly from laryngeal chemoreflexes in response to liquid/gastric contents) produce exaggerated apnoeic responses. The immature respiratory centre has a blunted response to CO₂ and an exaggerated response to inhibitory stimuli. The Hering-Breuer reflex (E) is more prominent in preterm infants but is not the primary cause of pathological apnoea.
Q139 [SBA] (Fetal/Neonatal) — A term neonate is delivered through thick meconium-stained liquor and develops respiratory distress. The most likely pathophysiological mechanism contributing to the respiratory distress is: A) Meconium acts as a direct toxin to type I pneumocytes causing necrosis B) Meconium obstructs small airways, causing a ball-valve effect with air trapping and hyperinflation C) Meconium induces surfactant overproduction leading to alveolar collapse D) Meconium triggers a Type IV hypersensitivity reaction in the neonatal lung E) Meconium dilates pulmonary capillaries, increasing V/Q mismatch
Answer: B In meconium aspiration syndrome (MAS), meconium particles obstruct small airways, creating a ball-valve effect — air can enter during inspiration (when airways are distended) but cannot exit during expiration (when airways narrow), leading to air trapping, hyperinflation, and increased risk of pneumothorax. Later, meconium components (bile acids) inactivate surfactant, causing atelectasis. The combination of hyperinflation and atelectasis creates severe V/Q mismatch.
Q140 [SBA] (Pathology) — A 52-year-old woman presents with a 3-month history of postmenopausal bleeding. Transvaginal ultrasound shows an endometrial thickness of 11 mm. Endometrial biopsy shows a proliferation of atypical glands with a cribriform pattern, back-to-back glands without intervening stroma, and nuclear pleomorphism. What is the most likely histological diagnosis? A) Simple endometrial hyperplasia without atypia B) Complex endometrial hyperplasia without atypia C) Endometrioid adenocarcinoma, FIGO grade 1 D) Endometrial intraepithelial neoplasia (EIN) E) Serous endometrial carcinoma
Answer: D (or technically, the most appropriate is D — Endometrial Intraepithelial Neoplasia) Endometrial intraepithelial neoplasia (EIN) is the preferred term for premalignant endometrial lesions that were previously called complex atypical hyperplasia. Key histological features include: a clonal proliferation of architecturally crowded glands (back-to-back, cribriform), cytological atypia (nuclear enlargement, pleomorphism, prominent nucleoli), and loss of intervening stroma. The absence of myometrial invasion or desmoplasia distinguishes EIN from frank adenocarcinoma.
Q141 [SBA] (Pathology) — A 44-year-old woman with menorrhagia undergoes hysteroscopic myomectomy. The resected specimen consists of whorled, white tissue with areas of cystic degeneration. Histology shows interlacing bundles of smooth muscle cells with areas of hyaline degeneration. No nuclear atypia or tumour cell necrosis is present. Which of the following degenerative changes is most commonly seen in uterine leiomyomas? A) Myxoid degeneration B) Cystic degeneration C) Hyaline degeneration (hyalinisation) D) Sarcomatous degeneration E) Haemorrhagic (red) degeneration
Answer: C Hyaline degeneration (hyalinisation) is the most common degenerative change in leiomyomas, seen in ~60% of cases. It appears as eosinophilic, acellular, homogeneous material replacing the smooth muscle fibres. Red (haemorrhagic) degeneration is classically associated with pregnancy. Cystic and myxoid degenerations are less common. Sarcomatous degeneration is rare (<0.1–0.5% — E is not "most commonly seen").
Q142 [MBA] (Pathology) — Which of the following are recognised histological features of high-grade serous ovarian carcinoma? (Select all that apply.) A) Solid, papillary, and slit-like architectural patterns B) Prominent psammoma bodies C) Marked nuclear pleomorphism with high mitotic rate D) Extensive necrosis E) CK7 negativity and WT1 negativity
Answer: A, B, C, D High-grade serous ovarian carcinoma is the most common epithelial ovarian malignancy. Histological features include: complex architecture (solid, papillary, slit-like spaces — A), psammoma bodies (concentric calcifications — B), high-grade nuclear atypia with frequent mitoses (C), and necrosis (D). Immunohistochemically, these tumours are typically CK7-positive and WT1-positive (E is false — they are CK7+ and WT1+, differentiating them from endometrioid and mucinous carcinomas).
Q143 [SBA] (Pathology) — A 48-year-old woman undergoes a total hysterectomy for a 14-week size fibroid uterus. Histology of the endometrium reveals secretory phase endometrium with a focus of adenomyosis. Which of the following best describes the histological definition of adenomyosis? A) Endometrial tissue located within the myometrium, more than 2.5 mm from the endomyometrial junction B) Endometrial glands and stroma present in the myometrium with adjacent smooth muscle hyperplasia C) Endometrial tissue within the myometrium with associated lymphocytic infiltration D) Islands of endometrial stroma only, without glands, within the myometrium E) Myometrial invasion by atypical endometrial glands
Answer: B Adenomyosis is defined by the presence of endometrial glands AND stroma within the myometrium, typically more than one high-power field (or ~2.5 mm) from the basal endometrium, accompanied by smooth muscle hyperplasia/hypertrophy of the surrounding myometrium. The smooth muscle hyperplasia is a key component. Endometrial stroma alone (without glands — D) is not sufficient. The absence of cytological atypia distinguishes it from malignancy (E).
Q144 [SBA] (Pathology) — A 35-year-old woman presents with acute lower abdominal pain and vaginal bleeding. Urine pregnancy test is positive. Transvaginal ultrasound shows an empty uterine cavity with a thickened endometrium and a 3 cm left adnexal mass. A laparoscopy confirms a left tubal ectopic pregnancy. Which of the following histological features is most helpful in confirming the diagnosis on the salpingectomy specimen? A) Presence of decidualised endometrium in the tube B) Presence of chorionic villi with trophoblast within the tubal lumen C) Haemosiderin-laden macrophages in the tubal wall D) Necrosis of the tubal wall with associated suppurative inflammation E) Tubal epithelial hyperplasia with papillary projections
Answer: B The definitive histopathological diagnosis of tubal ectopic pregnancy requires the identification of chorionic villi (with or without trophoblast) within the tubal lumen or wall. Implantation sites typically show the "implantation reaction" with trophoblast infiltration of the tubal wall, vascular invasion, and haemorrhage. Decidualisation (A) can occur in the tube from hormonal stimulation and is not diagnostic. Haemosiderin-laden macrophages (C) suggest old haemorrhage but are not specific.
Q145 [MBA] (Pathology) — Which of the following are known aetiological factors in the development of carcinoma of the vulva? (Select all that apply.) A) Lichen sclerosus B) HPV infection (particularly HPV-16, 18, 33) C) Differentiated vulval intraepithelial neoplasia (dVIN) D) Paget's disease of the vulva E) Cigarette smoking
Answer: A, B, C, E Vulval squamous cell carcinoma develops through two pathways: 1) HPV-related pathway (B) associated with usual-type VIN, younger women; and 2) HPV-independent pathway associated with lichen sclerosus (A), differentiated VIN (C), and chronic inflammation. Cigarette smoking (E) is a risk factor for both pathways. Paget's disease of the vulva (D) is a distinct entity (intraepithelial adenocarcinoma) and is not a precursor of squamous cell carcinoma.
Q146 [SBA] (Pathology) — A 56-year-old woman presents with abdominal distension and a pelvic mass. Serum CA125 is 2200 U/mL. At laparotomy, there is a 12 cm ovarian mass with papillary projections on the surface. Histology shows papillary fronds lined by stratified epithelial cells with severe nuclear atypia, numerous mitotic figures, and extensive necrosis. The tumour cells are WT1-positive and p53 shows a mutation pattern (diffuse strong nuclear staining). What is the most likely diagnosis? A) Primary mucinous ovarian carcinoma B) High-grade serous ovarian carcinoma (HGSC) C) Granulosa cell tumour D) Metastatic colorectal carcinoma to the ovary E) Clear cell ovarian carcinoma
Answer: B High-grade serous ovarian carcinoma (HGSC) is characterised by high-grade nuclear atypia, high mitotic rate, papillary architecture, necrosis, and p53 mutation (demonstrated by diffuse strong nuclear staining on IHC — the "overexpression" pattern). WT1 positivity and p53 mutation pattern are highly characteristic of HGSC and help distinguish it from other ovarian carcinomas. Mucinous carcinoma (A) is typically WT1-negative. Clear cell carcinoma (E) is associated with endometriosis and is WT1-negative.
Q147 [SBA] (Pathology) — A 60-year-old woman with a 5-year history of lichen sclerosus develops a 2 cm ulcerated lesion on the left labium minus. Biopsy shows invasive squamous cell carcinoma arising in a background of differentiated VIN (dVIN). Which of the following is the most common histological subtype of vulval squamous cell carcinoma? A) Verrucous carcinoma B) Basaloid carcinoma C) Keratinising squamous cell carcinoma D) Warty (condylomatous) carcinoma E) Spindle cell carcinoma
Answer: C Keratinising squamous cell carcinoma is the most common histological subtype of vulval SCC, accounting for ~65–80% of cases. It is typically associated with differentiated VIN (dVIN) and lichen sclerosus (HPV-independent pathway). Basaloid (B) and warty (D) subtypes are more commonly associated with usual-type VIN and high-risk HPV infection. Verrucous carcinoma (A) is a rare, low-grade variant.
Q148 [SBA] (Pathology) — A 34-year-old woman undergoes cervical screening. Cytology shows high-grade squamous intraepithelial lesion (HSIL, CIN 2–3). A colposcopy-directed cervical biopsy confirms CIN 3. Which of the following best describes the natural history of untreated CIN 3? A) Spontaneous regression occurs in >80% of cases within 2 years B) Approximately 30% may progress to invasive carcinoma over 10–30 years if untreated C) All CIN 3 lesions will progress to invasive cancer within 5 years D) CIN 3 always contains HPV-16 or HPV-18 E) CIN 3 cannot regress in women under 30 years of age
Answer: B The natural history of CIN 3: approximately 30% of untreated CIN 3 lesions may progress to invasive carcinoma over 10–30 years (B). Some lesions regress, particularly in younger women, but the regression rate for CIN 3 is significantly lower than for CIN 1–2. CIN 3 is considered a true premalignant lesion. Most (but not all) CIN 3 lesions are associated with high-risk HPV, with HPV-16 being the most common (D is false — not all contain 16/18).
Q149 [MBA] (Pathology) — Which of the following immunohistochemical markers are typically positive in endometrial stromal sarcoma (low grade)? (Select all that apply.) A) CD10 B) ER (oestrogen receptor) C) Desmin D) WT1 E) h-caldesmon
Answer: A, B Low-grade endometrial stromal sarcoma (LG-ESS) is typically positive for CD10 (A) and ER/PR (B). CD10 is the most commonly used marker but is not entirely specific. Desmin (C) and h-caldesmon (E) are markers of smooth muscle differentiation and would be positive in leiomyosarcoma, helping to distinguish it from ESS. WT1 (D) is not typically positive in ESS.
Q150 [SBA] (Clinical/Surgical) — A 34-year-old woman with stage IB2 cervical cancer (tumour 5 cm) undergoes radical chemoradiotherapy rather than radical hysterectomy. Which of the following best describes the rationale for choosing chemoradiotherapy over surgery for this stage of disease? A) Surgery is contraindicated because of the tumour size and risk of parametrial involvement B) Chemoradiotherapy is preferred for bulky IB2 disease due to superior oncological outcomes compared to surgery C) Surgery is preferred but the patient is too young for definitive radiotherapy D) Chemoradiotherapy is only indicated for stage IIB or higher cervical cancer E) Surgery plus adjuvant radiotherapy has fewer complications than chemoradiotherapy alone
Answer: B For FIGO stage IB2 cervical cancer (tumour ≥4 cm), current evidence (including the EORTC 55994 trial) shows that chemoradiotherapy offers comparable or superior oncological outcomes to radical hysterectomy with potentially less morbidity. Bulky IB2 disease has a high risk of parametrial involvement, lymphovascular space invasion, and nodal metastases. Chemoradiotherapy (pelvic EBRT + brachytherapy + concurrent cisplatin-based chemotherapy) is the standard of care in many guidelines, though individualised treatment decisions are made in multidisciplinary settings.
Q151 [SBA] (Pharmacology) — A 32-year-old woman with severe endometriosis is being treated with a GnRH agonist (leuprolide) plus add-back hormone therapy (oestrogen + progestogen). Which of the following best describes the rationale for add-back therapy? A) Add-back therapy prevents the initial "flare" effect of GnRH agonists B) Add-back therapy reduces hypo-oestrogenic side effects without compromising endometriosis suppression C) Add-back therapy enhances the downregulation of pituitary GnRH receptors D) Add-back therapy is required to prevent endometrial hyperplasia during GnRH agonist use E) Add-back therapy prolongs the duration of action of the GnRH agonist
Answer: B Add-back hormone therapy (typically continuous combined oestrogen + progestogen or tibolone) is used to mitigate the adverse effects of prolonged hypo-oestrogenism (vasomotor symptoms, bone loss, vaginal dryness) induced by GnRH agonist therapy. The key concept is that the "oestrogen threshold hypothesis" suggests that low-dose add-back therapy can maintain bone density and quality of life without stimulating endometriotic lesions. Add-back does not affect the flare (A).
Q152 [SBA] (Pharmacology) — A 27-year-old woman with a history of recurrent early pregnancy loss is diagnosed with antiphospholipid syndrome (APS). She is started on low-dose aspirin and low molecular weight heparin (enoxaparin) 40 mg daily. Which of the following best describes the mechanism by which aspirin improves pregnancy outcomes in APS? A) Selective COX-2 inhibition reduces placental inflammation B) Irreversible inhibition of platelet COX-1 reduces thromboxane A₂ synthesis C) Aspirin enhances antithrombin III activity similar to heparin D) Aspirin directly inhibits the binding of antiphospholipid antibodies to β₂-glycoprotein I E) Aspirin increases prostacyclin (PGI₂) production in the endothelium
Answer: B Low-dose aspirin (75–100 mg daily) irreversibly inhibits COX-1 in platelets, reducing the production of thromboxane A₂ (a potent vasoconstrictor and platelet aggregant). At low doses, aspirin spares endothelial prostacyclin (PGI₂) production (E is wrong — high doses inhibit both). This shifts the balance toward vasodilation and anti-aggregation. In APS, this reduces the thrombotic tendency that underlies placental insufficiency and pregnancy loss.
Q153 [MBA] (Pharmacology) — Which of the following drugs are considered compatible with breastfeeding with no or minimal risk to the infant? (Select all that apply.) A) Paracetamol (acetaminophen) B) Ibuprofen C) Codeine D) Sertraline E) Atenolol
Answer: A, B, D Paracetamol (A) and ibuprofen (B) are compatible with breastfeeding and are the analgesics of choice. Sertraline (D) is the preferred SSRI in breastfeeding due to low milk/plasma ratio. Codeine (C) is NOT recommended due to the risk of ultra-rapid metabolisers (CYP2D6 polymorphism) producing toxic morphine levels in breastmilk, leading to neonatal respiratory depression. Atenolol (E) accumulates in breastmilk and can cause neonatal bradycardia — labetalol or propranolol are preferred.
Q154 [SBA] (Pharmacology) — A 31-year-old woman with epilepsy on lamotrigine 200 mg twice daily becomes pregnant. At 20 weeks gestation, she experiences a breakthrough seizure. Her lamotrigine level is subtherapeutic. By what approximate percentage should lamotrigine doses be increased during pregnancy due to enhanced clearance? A) 10–20% B) 25–50% C) 50–200% D) 200–300% E) Lamotrigine clearance does not change in pregnancy
Answer: C Lamotrigine clearance significantly increases in pregnancy due to enhanced glucuronidation (UGT1A4 induction), particularly in the second and third trimesters. Dose increases of 50–200% (or even more) are often required to maintain therapeutic levels. Therapeutic drug monitoring is recommended, with pre-conception baseline levels and regular monitoring through pregnancy. Postpartum, doses must be reduced rapidly (over 1–3 weeks) to avoid toxicity.
Q155 [MBA] (Pharmacology) — Which of the following medications are used off-label (or under specialist guidance) for the prevention of preterm birth in women with a short cervix? (Select all that apply.) A) Vaginal progesterone (200 mg, micronised) B) Oral nifedipine C) Cervical cerclage D) Atosiban (oxytocin receptor antagonist) E) 17α-hydroxyprogesterone caproate
Answer: A, C Vaginal progesterone (A) is the first-line pharmacological agent for prevention of preterm birth in women with a short cervix (<25 mm) on transvaginal ultrasound, with or without prior preterm birth. Cervical cerclage (C) is a surgical (not pharmacological) intervention indicated for ultrasound-indicated short cervix with prior preterm birth. Oral nifedipine (B) and atosiban (D) are used for acute tocolysis (suppression of preterm labour), not for prevention. 17α-hydroxyprogesterone caproate (E) is not licensed/approved in the UK for this indication regardless of cervical length.
Q156 [SBA] (Pharmacology) — A 33-year-old woman at 34 weeks gestation presents with severe hypertension (BP 172/108 mmHg). Labetalol 200 mg orally is administered. Thirty minutes later, her blood pressure is 168/106 mmHg. Which of the following is the most appropriate next step? A) Administer a second dose of labetalol 200 mg orally B) Start intravenous labetalol infusion C) Administer intravenous hydralazine 5 mg D) Administer oral nifedipine 10 mg E) Deliver by emergency caesarean section
Answer: A If blood pressure remains severely elevated 30 minutes after the first dose of oral labetalol, a second oral dose can be given (the onset of oral labetalol is 20–30 minutes, with peak effect at 1–2 hours). The NICE and RCOG guidelines recommend repeating oral labetalol 200 mg at 30-minute intervals if needed, up to a maximum of 600 mg. Intravenous therapy is reserved for refractory hypertension. Emergency delivery is not indicated for BP management alone without other maternal/fetal concerns.
Q157 [SBA] (Pharmacology) — A 30-year-old woman with migraine headaches is planning pregnancy and asks about medication safety. Which of the following is the most appropriate acute migraine treatment option in pregnancy? A) Sumatriptan (oral or subcutaneous) B) Ergotamine tartrate C) Naproxen throughout pregnancy D) Topiramate as a prophylactic agent E) Morphine sulphate for acute attacks
Answer: A Sumatriptan (a 5-HT₁B/1D agonist) is considered relatively safe in pregnancy based on registry data and large cohort studies, though it should be used at the lowest effective dose. Ergotamine (B) is contraindicated in pregnancy (uterotonic and vasoconstrictive effects causing fetal hypoxia). Naproxen (C) should be avoided in the third trimester (risk of premature ductus arteriosus closure and oligohydramnios). Topiramate (D) is a recognised teratogen (cleft lip/palate risk).
Q158 [SBA] (Pharmacology) — A 39-year-old woman at 37 weeks gestation develops symptomatic DVT confirmed by compression ultrasound. She has no contraindications to anticoagulation. Which of the following is the recommended first-line anticoagulant for the treatment of VTE in pregnancy? A) Unfractionated heparin (UFH) intravenous infusion B) Low molecular weight heparin (LMWH) — weight-adjusted subcutaneous dosing C) Warfarin (target INR 2–3) D) Rivaroxaban E) Fondaparinux
Answer: B Low molecular weight heparin (LMWH) is the first-line agent for the treatment of acute VTE in pregnancy, given subcutaneously in weight-adjusted doses (e.g., enoxaparin 1.5 mg/kg once daily or 1 mg/kg twice daily). LMWH is preferred over UFH due to better bioavailability, more predictable dosing, lower risk of heparin-induced thrombocytopenia, and lower risk of osteoporosis. Warfarin (C) and DOACs (D — rivaroxaban) cross the placenta and are contraindicated in pregnancy.
Q159 [MBA] (Pharmacology) — Which of the following drugs are classified as FDA Pregnancy Category D (evidence of human fetal risk, but benefits may outweigh risks)? (Select all that apply.) A) Phenytoin B) Valproate C) ACE inhibitors (in second and third trimesters) D) Methotrexate E) Lithium
Answer: A, C, E Note: The FDA replaced pregnancy letter categories in 2015 with the Pregnancy and Lactation Labeling Rule, but historically: Phenytoin (A — fetal hydantoin syndrome, IUGR), ACE inhibitors (C — fetal renal damage, oligohydramnios in second/third trimester), and Lithium (E — Ebstein's anomaly risk, ~0.05–0.1%) are Category D. Valproate (B) is Category X (contraindicated — highest risk of neural tube defects and neurodevelopmental delay). Methotrexate (D) is Category X (contraindicated — teratogenic, abortifacient).
Q160 [SBA] (Pharmacology) — A 25-year-old woman with a copper intrauterine device (IUD) in situ presents with 3-day history of vaginal discharge, fever, and pelvic pain. A diagnosis of pelvic inflammatory disease (PID) is made. The IUD is removed. Which of the following is the most appropriate empiric antibiotic regimen for PID? A) Metronidazole 400 mg BD alone for 14 days B) Single dose azithromycin 1 g C) Ceftriaxone 1 g IM single dose plus doxycycline 100 mg BD for 14 days ± metronidazole D) Amoxicillin 500 mg TDS for 7 days E) Ciprofloxacin 500 mg BD for 14 days
Answer: C The recommended empiric regimen for PID (per BASHH/RCOG guidelines) covers Chlamydia trachomatis, Neisseria gonorrhoeae, and anaerobes. The regimen of ceftriaxone (for gonorrhoea) plus doxycycline (for Chlamydia) plus metronidazole (for anaerobes) provides comprehensive coverage. Single-dose azithromycin (B) is not sufficient for PID. The IUD should be removed if PID is diagnosed, as the IUD can serve as a nidus for infection.
Q161 [SBA] (Microbiology) — A 30-year-old woman presents with a painless ulcer on her vulva of 4 weeks duration. The ulcer is 1.5 cm, has rolled edges, and a clean base. No lymphadenopathy is noted. Dark-field microscopy of the exudate shows spirochetes. Which of the following is the most likely diagnosis? A) Herpes simplex virus infection B) Primary syphilis (Treponema pallidum) C) Chancroid (Haemophilus ducreyi) D) Lymphogranuloma venereum (Chlamydia trachomatis serovars L1–L3) E) Granuloma inguinale (Klebsiella granulomatis)
Answer: B A painless, indurated ulcer with rolled edges and a clean base is the classic description of a primary chancre of syphilis. Dark-field microscopy (the gold standard for early primary syphilis) demonstrates motile spirochetes (Treponema pallidum). Serological testing (VDRL/RPR and TPHA) is also used. Syphilis in pregnancy can cause congenital syphilis, making timely diagnosis and treatment (with penicillin) critical.
Q162 [MBA] (Microbiology) — Which of the following statements regarding hepatitis B virus (HBV) infection in pregnancy are correct? (Select all that apply.) A) Hepatitis B is a DNA virus transmitted through blood and body fluids B) Vertical transmission occurs primarily during the second trimester C) The risk of vertical transmission is highest when maternal HBV DNA levels are >200,000 IU/mL D) All newborns of HBsAg-positive mothers should receive hepatitis B immunoglobulin (HBIG) and vaccine within 24 hours of birth E) Breastfeeding is contraindicated if the mother is HBsAg-positive
Answer: A, C, D HBV is a DNA virus (A). Vertical transmission occurs primarily during labour and delivery (intrapartum), not during the second trimester (B is false). High maternal viral load (>200,000 IU/mL or 6–7 log₁₀ copies/mL) correlates with transmission risk despite passive-active immunoprophylaxis (C). All infants of HBsAg-positive mothers should receive HBIG plus HBV vaccine within 24 hours (D). Breastfeeding is NOT contraindicated — the infant is already protected by immunisation (E is false).
Q163 [SBA] (Microbiology) — A 28-year-old woman presents with acute-onset dysuria, frequency, and urgency at 32 weeks gestation. Urine dipstick is positive for nitrites and leucocytes. Which of the following is the most common causative organism of asymptomatic bacteriuria and acute cystitis in pregnancy? A) Group B Streptococcus (GBS) B) Escherichia coli C) Klebsiella pneumoniae D) Staphylococcus saprophyticus E) Proteus mirabilis
Answer: B Escherichia coli is the most common causative organism for both asymptomatic bacteriuria (2–10% of pregnant women) and acute cystitis in pregnancy, accounting for 70–80% of cases. GBS (A) is common as a coloniser and can cause UTI but is less frequent. Pregnant women with bacteriuria should be treated due to the increased risk of pyelonephritis (20–30% if untreated vs 2–4% if treated).
Q164 [SBA] (Microbiology) — A labouring woman at 39 weeks gestation has a fever of 38.8°C, tachycardia, and uterine tenderness. Artificial rupture of membranes was performed 18 hours ago. A diagnosis of chorioamnionitis is made. Which of the following organisms is most commonly implicated in acute chorioamnionitis? A) Group A Streptococcus (Streptococcus pyogenes) B) Ureaplasma urealyticum C) Bacteroides fragilis D) Candida albicans E) Mycoplasma hominis
Answer: B Ureaplasma urealyticum and Mycoplasma hominis are the most common organisms isolated from the amniotic fluid in chorioamnionitis, particularly in cases with preterm premature rupture of membranes (PPROM). Other common organisms include Gardnerella vaginalis, anaerobic bacteria, E. coli, and GBS. Chorioamnionitis is typically polymicrobial, ascending from the lower genital tract.
Q165 [SBA] (Microbiology) — A 32-year-old woman undergoing IVF has a routine vaginal swab that is positive for group B Streptococcus (GBS) on enrichment culture. She is currently 18 weeks pregnant with a singleton pregnancy. Which of the following is the most appropriate management? A) Treat with oral penicillin V now to eradicate GBS B) Treat with oral clindamycin now due to risk of preterm birth C) No antenatal treatment is required; intrapartum antibiotic prophylaxis (IAP) will be offered when in labour D) Repeat the swab at 28 weeks to confirm persistence E) Recommend elective caesarean section to prevent neonatal GBS disease
Answer: C In the UK (based on RCOG green-top guideline), antenatal treatment of GBS colonisation is not recommended because eradication is often temporary and recolonisation occurs. Current UK practice uses a risk-based approach (not universal screening) for offering intrapartum antibiotic prophylaxis (IAP). If GBS is detected incidentally (as in this case), IAP should be offered when the woman presents in labour. Repeat swabs (D) are not necessary.
Q166 [MBA] (Microbiology) — Which of the following statements regarding human papillomavirus (HPV) vaccination are correct? (Select all that apply.) A) The HPV vaccine is a live attenuated virus vaccine B) The UK vaccination programme uses a bivalent vaccine targeting HPV-16 and HPV-18 C) Vaccination provides protection against HPV types that the individual has already acquired D) The vaccine is most effective when given before sexual debut E) HPV vaccination has been shown to reduce the incidence of cervical intraepithelial neoplasia (CIN) in population-based studies
Answer: B, D, E The UK programme uses the bivalent Cervarix vaccine (B — targets HPV-16 and HPV-18, with cross-protection against other types). The vaccine is a recombinant virus-like particle (VLP) vaccine, not live (A is false). The vaccine is prophylactic, not therapeutic — it does not treat existing infections (C is false). Maximum efficacy is achieved when given before sexual debut (D). Population data show significant reductions in CIN and genital warts (E).
Q167 [SBA] (Microbiology) — A 34-year-old woman at 28 weeks gestation presents with a 3-day history of watery vaginal discharge. Pooling is seen on speculum examination, and nitrazine paper turns blue. AmniSure (IGFBP-1) test is positive. Which of the following is the most important microbiological consideration in the context of preterm prelabour rupture of membranes (PPROM)? A) Chorioamnionitis is a contraindication to antenatal corticosteroids B) Erythromycin is recommended for prophylaxis against ascending infection C) Co-amoxiclav is the first-line prophylactic antibiotic D) Vaginal swabs should be taken only if the woman is febrile E) GBS prophylaxis is not indicated in PPROM
Answer: B According to the UK guidelines (RCOG), erythromycin is recommended for prophylaxis in PPROM to prolong pregnancy and reduce neonatal morbidity (the ORACLE I trial). Co-amoxiclav (C) is no longer recommended due to an increased risk of neonatal necrotising enterocolitis (NEC). Chorioamnionitis is an indication for delivery, not a contraindication to steroids (A). GBS prophylaxis should be given in labour regardless of PPROM (E).
Q168 [SBA] (Microbiology) — A 26-year-old woman presents with a 1-week history of frothy, green-yellow vaginal discharge with a foul odour. On speculum examination, the vaginal walls are erythematous with punctate haemorrhages ("strawberry cervix"). Which of the following is the most appropriate diagnostic test? A) KOH wet mount microscopy for hyphae B) Gram stain for clue cells C) Nucleic acid amplification test (NAAT) for Trichomonas vaginalis D) Viral culture for HSV E) Dark-field microscopy for spirochetes
Answer: C The clinical picture is classic for Trichomonas vaginalis infection — frothy, malodorous discharge with strawberry cervix (punctate haemorrhages). While wet mount microscopy (saline preparation) can show motile trichomonads, it has limited sensitivity (~60–70%). Nucleic acid amplification tests (NAATs) are now the gold standard with >95% sensitivity and specificity. Treatment is metronidazole 2 g orally single dose or 400–500 mg BD for 5–7 days.
Q169 [SBA] (Immunology) — A 28-year-old woman with known rheumatoid arthritis (RA) is taking adalimumab (anti-TNFα therapy). She is planning pregnancy. Which of the following best describes the placental transfer of adalimumab and its implications? A) Adalimumab (IgG1) crosses the placenta in the first trimester, posing a high risk of fetal malformations B) Adalimumab crosses the placenta most efficiently in the third trimester via FcRn-mediated transport C) Adalimumab cannot cross the placenta because it is a monoclonal antibody with high molecular weight D) Adalimumab is completely safe in pregnancy as it is inactivated by placental enzymes E) Adalimumab should be stopped at least 6 months before conception
Answer: B Adalimumab is a humanised IgG1 monoclonal antibody. Like all IgG1 antibodies, it is actively transported across the placenta via the neonatal Fc receptor (FcRn) on syncytiotrophoblast cells. This transport is minimal in the first trimester and increases exponentially in the second and third trimesters (maximal after ~28 weeks). Current guidelines suggest adalimumab can be continued through the first and second trimesters but should be stopped in the third trimester (around 30 weeks) to minimise fetal exposure.
Q170 [SBA] (Immunology) — A 32-year-old primigravida at 12 weeks gestation has a routine blood group and antibody screen. She is group O RhD-positive with a positive antibody screen. The antibody is identified as anti-K (Kell). Which of the following best describes the mechanism by which anti-K causes haemolytic disease of the fetus and newborn (HDFN)? A) Anti-K antibodies cause complement-mediated intravascular haemolysis more efficiently than anti-D B) Anti-K antibodies suppress fetal erythropoiesis by destroying erythroid progenitor cells in the fetal liver C) Anti-K antibodies cross the placenta less efficiently than anti-D, so the disease is milder D) Anti-K antibodies cause only jaundice in the newborn, never anaemia E) Anti-K antibodies are naturally occurring IgM and do not cause HDFN
Answer: B Anti-K (Kell) HDFN is unique because Kell antigens are expressed not only on mature RBCs but also on erythroid progenitor cells (burst-forming units, colony-forming units) in the fetal liver and spleen. Anti-K antibodies destroy these precursors, causing anaemia primarily through suppression of erythropoiesis (rather than haemolysis of mature RBCs). This is why anti-K HDFN can cause severe anaemia with unexpectedly low bilirubin levels, and the anaemia can be more refractory to intrauterine transfusion.
Q171 [MBA] (Immunology) — Which of the following are components of the innate immune system that are active at the maternal-fetal interface? (Select all that apply.) A) Natural killer (NK) cells (uterine or decidual NK cells) B) Macrophages C) Complement proteins D) T cell receptors with MHC restriction E) Pattern recognition receptors (Toll-like receptors, TLRs)
Answer: A, B, C, E The innate immune system at the maternal-fetal interface includes: uterine NK cells (uNK — the most abundant lymphocyte in decidua — A), macrophages (B — second most abundant), complement proteins (C), and pattern recognition receptors like TLRs expressed on trophoblasts and decidual cells (E). T cell receptors with MHC restriction (D) are components of the ADAPTIVE immune system, not innate.
Q172 [SBA] (Immunology) — A 34-year-old woman with a history of recurrent miscarriage (5 consecutive first-trimester miscarriages) is investigated. She has positive lupus anticoagulant, anticardiolipin IgG antibodies (moderate titre, 42 GPL units), and anti-β₂ glycoprotein I antibodies. She is diagnosed with antiphospholipid syndrome (APS). Which of the following immunological mechanisms is most directly responsible for the thrombotic tendency in APS? A) Antibody-mediated depletion of protein C and S B) Binding of antiphospholipid antibodies to β₂GPI on endothelial cells, activating the endothelium C) Direct antibody activation of platelet glycoprotein IIb/IIIa receptors D) Complement inhibition by antiphospholipid antibodies E) Antibody-mediated destruction of tissue factor pathway inhibitor
Answer: B The primary pathogenic mechanism in APS is the binding of antiphospholipid antibodies (aPL) to β₂-glycoprotein I (β₂GPI) on the surface of endothelial cells, monocytes, and trophoblasts. This binding activates the endothelium (via the TLR4 and annexin A2 pathways), upregulates adhesion molecules (E-selectin, VCAM-1, ICAM-1), and promotes a prothrombotic state through tissue factor expression and disruption of the annexin A5 anticoagulant shield. Treatment is anticoagulation with heparin and aspirin.
Q173 [SBA] (Immunology) — A 30-year-old woman with Hashimoto's thyroiditis is found to be anti-thyroid peroxidase (anti-TPO) antibody positive with a TSH of 4.5 mIU/L. She is planning pregnancy. Which of the following best describes the clinical significance of anti-TPO antibodies in reproductive-age women? A) Anti-TPO antibodies directly cause recurrent miscarriage by cross-reacting with trophoblast antigens B) Anti-TPO positivity is associated with an increased risk of unexplained subfertility and miscarriage C) Anti-TPO antibodies protect against postpartum thyroiditis D) Anti-TPO antibodies are a marker of poor ovarian reserve E) Anti-TPO antibodies require no treatment and have no reproductive implications
Answer: B Anti-thyroid peroxidase (anti-TPO) antibodies are a marker of autoimmune thyroid disease and are present in most women with Hashimoto's thyroiditis. They are associated with an increased risk of unexplained subfertility and miscarriage (risk ratio ~1.5–2.0). The mechanism may involve mild thyroid dysfunction or shared autoimmunity affecting implantation. Current guidance recommends checking TSH and offering levothyroxine if TSH >2.5 mIU/L in pregnancy (or pre-conception if planning pregnancy).
Q174 [SBA] (Biochemistry) — A 22-year-old woman presents with recurrent episodes of vomiting, abdominal pain, and altered mental status during the luteal phase of her menstrual cycle. Urine dipstick is strongly positive for ketones. Serum amino acids show elevated glycine. Which of the following metabolic disorders should be suspected? A) Acute intermittent porphyria B) Ornithine transcarbamylase (OTC) deficiency C) Maple syrup urine disease D) Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency E) Glycogen storage disease type Ia (von Gierke's disease)
Answer: A Acute intermittent porphyria (AIP) is an autosomal dominant disorder caused by deficiency of porphobilinogen deaminase (PBGD) in the haem synthesis pathway. It presents with episodic attacks of abdominal pain, neuropsychiatric symptoms, and autonomic dysfunction. Attacks are triggered by hormonal changes (including the luteal phase of the menstrual cycle — oestrogen/progesterone induce hepatic ALAS, the rate-limiting enzyme of haem synthesis). Elevated glycine is a biochemical clue as glycine is a substrate for δ-aminolevulinic acid (ALA) synthesis.
Q175 [MBA] (Biochemistry) — Which of the following are sources of ammonia in the human body? (Select all that apply.) A) Deamination of amino acids in the liver B) Bacterial metabolism in the colon C) Hydrolysis of glutamine in the kidneys D) Purine nucleotide degradation E) β-oxidation of fatty acids
Answer: A, B, C, D Ammonia is generated from: (A) deamination of amino acids (primarily in the liver), (B) bacterial urease activity in the colon (producing ammonia from urea), (C) renal glutamine hydrolysis (a source of ammonia for acid-base regulation), and (D) purine nucleotide degradation (adenine → adenosine → inosine → hypoxanthine → xanthine → uric acid, with ammonia released at some steps). β-oxidation of fatty acids (E) does NOT directly produce ammonia — it produces acetyl-CoA, FADH₂, and NADH.
Q176 [SBA] (Biochemistry) — A 30-year-old woman with known homocystinuria is planning pregnancy. She has a history of thromboembolism and lens dislocation. Which of the following best describes the biochemical basis of homocystinuria? A) Deficiency of phenylalanine hydroxylase leading to homocysteine accumulation B) Deficiency of cystathionine β-synthase leading to accumulation of homocysteine and methionine C) Deficiency of methylenetetrahydrofolate reductase (MTHFR) D) Defect in homocysteine transport across the cell membrane E) Increased catabolism of homocysteine to cysteine
Answer: B Classic homocystinuria is caused by deficiency of cystathionine β-synthase (CBS), an enzyme in the transsulphuration pathway that converts homocysteine to cystathionine. This leads to accumulation of homocysteine and methionine. Clinical features include: ectopia lentis (lens dislocation — hallmark), thromboembolism (leading cause of morbidity/mortality), intellectual disability, marfanoid habitus, and osteoporosis. About 50% of cases are pyridoxine (vitamin B6)-responsive.
Q177 [SBA] (Biochemistry) — A 36-year-old woman at 12 weeks gestation has a routine first-trimester combined screening test. Her serum free β-hCG is 2.5 MoM and PAPP-A is 0.45 MoM. Her nuchal translucency is 2.0 mm (1.3 MoM). The adjusted risk for trisomy 21 is 1:150. Which of the following best describes the biochemical basis of elevated hCG in trisomy 21 pregnancies? A) Placental hyperplasia with increased syncytiotrophoblast mass B) Fetal overexpression of the hCG α-subunit gene on chromosome 21 C) Immature villous trophoblast with impaired hCG processing D) Increased production of hCG due to fetal anaemia E) Maternal hypothalamic-pituitary stimulation by placental steroids
Answer: B The hCG molecule shares its α-subunit with LH, FSH, and TSH (encoded on chromosome 6q12), while the β-subunit (β-hCG) is encoded by a gene cluster on chromosome 19q13.3. Interestingly, the β-hCG gene cluster is NOT on chromosome 21. The actual reason for elevated hCG in trisomy 21 is thought to be related to altered differentiation of villous trophoblast causing increased secretion. However, a key fact is that the β-hCG gene locus is on chromosome 19 (not 21). Let me clarify: The biochemical basis of elevated hCG in trisomy 21 is not fully understood, but it is thought to reflect immaturity of the placental villous tree and altered trophoblast gene expression, NOT directly due to the extra copy of chromosome 21 (since the β-hCG gene is on chromosome 19). The elevated hCG reflects placental dysfunction rather than a direct gene dosage effect.
Wait, I need to correct myself — the free β-hCG in trisomy 21 pregnancies is elevated, and the most accepted mechanism is that trisomy 21 placentas have delayed villous maturation with increased secretory activity of syncytiotrophoblast. The best answer here would relate to abnormal trophoblast differentiation.
Q178 [SBA] (Biochemistry) — A neonate is noted to have ambiguous genitalia at birth. The karyotype is 46,XX. Biochemical workup reveals elevated 17-hydroxyprogesterone (17-OHP) and elevated androstenedione. Which of the following is the most likely diagnosis? A) Complete androgen insensitivity syndrome B) 21-hydroxylase deficiency (classic congenital adrenal hyperplasia) C) 5α-reductase deficiency D) 17α-hydroxylase deficiency E) Placental aromatase deficiency
Answer: B 21-Hydroxylase deficiency (the most common form of congenital adrenal hyperplasia, >90% of cases) results in accumulation of 17-hydroxyprogesterone (the diagnostic biochemical marker), which is then shunted into the androgen pathway, producing excess androstenedione and testosterone. In a 46,XX infant, this causes virilisation/ambiguous genitalia (clitoromegaly, labial fusion). The elevated 17-OHP is the pathognomonic finding. Salt-wasting crisis (hyponatraemia, hyperkalaemia) occurs in ~75% of classic cases due to aldosterone deficiency.
Q179 [MBA] (Genetics) — Which of the following genetic conditions demonstrate anticipation (increasing severity or earlier age of onset in successive generations)? (Select all that apply.) A) Huntington's disease B) Fragile X syndrome C) Myotonic dystrophy type 1 D) Cystic fibrosis E) Sickle cell disease
Answer: A, B, C Genetic anticipation is a hallmark of trinucleotide repeat disorders. Huntington's disease (A — CAG repeat in HTT gene), Fragile X syndrome (B — CGG repeat in FMR1 gene), and Myotonic dystrophy type 1 (C — CTG repeat in DMPK gene) all show anticipation due to expansion of the repeat across generations. Cystic fibrosis (D) and sickle cell disease (E) are single-gene disorders without repeat expansion and do not show anticipation.
Q180 [SBA] (Genetics) — A 36-year-old woman undergoes amniocentesis at 16 weeks due to a high-risk NIPT result. The karyotype shows 46,XX,del(5)(p15.3). This microdeletion syndrome is associated with which of the following clinical features? A) Holoprosencephaly and cyclopia B) Cri-du-chat syndrome (cat-like cry, microcephaly, intellectual disability) C) Williams syndrome (supravalvular aortic stenosis, elfin facies) D) DiGeorge syndrome (conotruncal heart defects, hypoparathyroidism) E) Prader-Willi syndrome (hyperphagia, hypotonia)
Answer: B Deletion of the short arm of chromosome 5 (5p15.3 — 5p15.2) causes Cri-du-chat syndrome, characterised by: a high-pitched, cat-like cry in infancy (due to laryngeal abnormalities), microcephaly, hypertelorism, downslanting palpebral fissures, profound intellectual disability, and congenital heart disease (in ~20%). Williams syndrome (C) is due to 7q11.23 deletion. DiGeorge syndrome (D) is 22q11.2 deletion.
Q181 [SBA] (Genetics) — A 34-year-old woman has a chorionic villus sample that shows mosaic trisomy 16 on direct preparation, but the cultured karyotype is normal (46,XX). Which of the following is the most appropriate interpretation and counselling? A) The pregnancy is unaffected — no further follow-up is needed B) Mosaic trisomy 16 is a laboratory artefact with no clinical significance C) Confined placental mosaicism (CPM) for trisomy 16 carries a risk of fetal growth restriction D) The fetus has trisomy 16, requiring termination of pregnancy E) Amniocentesis is not indicated because the cultured CVS is normal
Answer: C Mosaic trisomy 16 detected on CVS that is not confirmed in cultured cells suggests confined placental mosaicism (CPM). Trisomy 16 is the most common autosomal trisomy in CVS. While the fetus is typically karyotypically normal (if confirmed by amniocentesis), CPM for trisomy 16 is associated with an increased risk of intrauterine growth restriction (IUGR), preterm birth, and adverse pregnancy outcomes. Amniocentesis for fetal karyotype confirmation is recommended (E is false — it should be offered).
Q182 [SBA] (Genetics) — A 40-year-old woman is found to have a male fetus on NIPT at 10 weeks. A follow-up amniocentesis at 16 weeks shows a karyotype of 47,XXY. Which of the following best describes the testicular histology in adults with 47,XXY? A) Normal spermatogenesis and Leydig cell function B) Seminiferous tubule hyalinisation and fibrosis with absent spermatogenesis C) Testicular microlithiasis with preserved Sertoli cell function D) Leydig cell hyperplasia with enhanced testosterone production E) Germ cell tumours (seminoma) developing in the first decade
Answer: B In Klinefelter syndrome (47,XXY), the seminiferous tubules undergo progressive hyalinisation and fibrosis after puberty, resulting in small, firm testes and azoospermia (absent spermatogenesis). Leydig cell function is impaired (not normal — D is false), leading to low-normal testosterone with elevated LH and FSH. The condition is one of the most common causes of male infertility (3% of infertile men). Adult height is typically above average with eunuchoid proportions.
Q183 [MBA] (Genetics) — Which of the following are mechanisms by which microRNAs (miRNAs) regulate gene expression? (Select all that apply.) A) Binding to complementary sequences in the 3' untranslated region (UTR) of target mRNAs B) Inhibition of mRNA translation without mRNA degradation C) Cleavage and degradation of target mRNA D) Direct binding to DNA to block transcription E) Modification of histone proteins associated with target genes
Answer: A, B, C MicroRNAs (miRNAs) are small (~22 nucleotide) non-coding RNAs that regulate gene expression post-transcriptionally. They bind to complementary sequences (seed sequences) primarily in the 3' UTR of target mRNAs (A). This binding can either inhibit translation (B — without mRNA degradation) or promote mRNA deadenylation and decay (C), depending on the degree of complementarity. miRNAs do NOT bind directly to DNA (D) or modify histones (E) — these are functions of other regulatory mechanisms.
Q184 [SBA] (Embryology) — A newborn is diagnosed with a congenital diaphragmatic hernia (Bochdalek type). Which of the following best describes the embryological origin of this defect? A) Failure of the pleuroperitoneal membranes to close the pericardio-peritoneal canal B) Abnormal fusion of the sternal and costal portions of the diaphragm C) Herniation through the oesophageal hiatus D) Failure of the mesentery of the foregut to fuse with the posterior abdominal wall E) Defect in the septum transversum, leaving a central diaphragmatic defect
Answer: A Bochdalek (posterolateral) congenital diaphragmatic hernia results from failure of the pleuroperitoneal membranes to fuse with the septum transversum and the body wall during weeks 8–10 of gestation, leaving a defect in the posterolateral diaphragm. This allows abdominal viscera to herniate into the thoracic cavity, compressing the developing lung and causing pulmonary hypoplasia. The majority (80–85%) occur on the left side. Morgagni hernias (B) are anterior retrosternal defects.
Q185 [SBA] (Embryology) — A female infant is born with an absent left kidney and a bicornuate uterus. These associated anomalies suggest a defect in the development of which embryological structure? A) Intermediate mesoderm B) Lateral plate mesoderm C) Paraxial mesoderm D) Endoderm of the hindgut E) Neural crest cells
Answer: A The kidneys develop from the intermediate mesoderm (which forms the nephrogenic cord), and the uterus and upper vagina develop from the paramesonephric (Müllerian) ducts, which also arise from intermediate mesoderm. Therefore, a defect in intermediate mesoderm development at around weeks 4–6 of gestation can simultaneously affect both renal and Müllerian duct development. This explains the well-known association between Müllerian duct anomalies (e.g., bicornuate uterus) and renal agenesis.
Q186 [MBA] (Embryology) — Which of the following structures are derived from the urogenital sinus in female development? (Select all that apply.) A) Lower one-third of the vagina B) The urethra C) The vestibular bulbs D) Bartholin's (greater vestibular) glands E) The ovaries
Answer: A, B, C, D The urogenital sinus gives rise to: the lower one-third of the vagina (A — the sinovaginal bulbs that form the vaginal plate; the upper 2/3 are Müllerian-derived), the urethra (B), vestibular bulbs (C — erectile tissue derived from genital tubercle), and Bartholin's glands (D — greater vestibular glands). The ovaries (E) develop from the gonadal ridge (mesoderm), not the urogenital sinus.
Q187 [SBA] (Embryology) — A neonate presents with a cystic swelling in the neck region along the anterior border of the sternocleidomastoid muscle. Ultrasound shows a cyst lined by respiratory epithelium with lymphoid tissue in the wall. This is most likely a remnant of which embryological structure? A) First branchial cleft B) Second branchial cleft C) Thyroglossal duct D) Thymopharyngeal duct E) Third branchial pouch
Answer: B A branchial cleft cyst (typically from the second branchial cleft) presents as a cystic swelling along the anterior border of the sternocleidomastoid muscle. Histologically, it is lined by stratified squamous or respiratory epithelium with abundant lymphoid tissue in the wall. These cysts usually present in the second or third decade of life. Thyroglossal duct cysts (C) are midline and move with swallowing. First branchial cleft cysts (A) are near the ear and angle of the mandible.
Q188 [SBA] (Embryology) — During embryonic development, the genital tubercle, urogenital folds, and labioscrotal swellings give rise to which female external genital structures? A) Genital tubercle → clitoris; urogenital folds → labia minora; labioscrotal swellings → labia majora B) Genital tubercle → labia majora; urogenital folds → clitoris; labioscrotal swellings → mons pubis C) Genital tubercle → labia minora; urogenital folds → labia majora; labioscrotal swellings → clitoris D) Genital tubercle → mons pubis; urogenital folds → clitoris; labioscrotal swellings → labia minora E) Genital tubercle → Bartholin's glands; urogenital folds → labia majora; labioscrotal swellings → clitoris
Answer: A In the absence of androgens (female development), the genital tubercle develops into the clitoris, the urogenital folds remain separate and form the labia minora, and the labioscrotal swellings fuse posteriorly to form the labia majora (they do not fuse in the midline as they do in male development to form the scrotum). This differentiation occurs under the influence of the absence of dihydrotestosterone and the presence of oestrogen.
Q189 [SBA] (Statistics) — A randomised controlled trial of 1000 women compares a new tocolytic drug (atosiban) versus placebo for the suppression of preterm labour. The results show that 75 out of 500 women (15%) in the atosiban group delivered within 48 hours, compared to 100 out of 500 women (20%) in the placebo group. The relative risk reduction (RRR) for delivery within 48 hours with atosiban is: A) 5% B) 15% C) 20% D) 25% E) 33%
Answer: D Relative risk (RR) = risk in treatment group / risk in control group = 15%/20% = 0.75. Relative risk reduction (RRR) = 1 − RR = 1 − 0.75 = 0.25 = 25%. The absolute risk reduction (ARR) = 20% − 15% = 5%. The number needed to treat (NNT) = 1/ARR = 1/0.05 = 20. The RRR describes the proportional reduction in risk relative to the control group.
Q190 [MBA] (Statistics) — In a study comparing trial of labour after caesarean (TOLAC) versus elective repeat caesarean section (ERCS), the results are presented as an odds ratio (OR) of 2.5 (95% CI 1.8–3.5) for uterine rupture in the TOLAC group. Which of the following interpretations are CORRECT? (Select all that apply.) A) Women undergoing TOLAC have 2.5 times the odds of uterine rupture compared to ERCS B) The association is statistically significant at the 5% level C) The odds ratio approximates the relative risk because the outcome is rare D) The p-value for this analysis is exactly 0.05 E) The attributable risk of uterine rupture with TOLAC is 2.5%
Answer: A, B, C The OR of 2.5 means the odds of uterine rupture in the TOLAC group is 2.5 times that in the ERCS group (A). Since the 95% CI (1.8–3.5) does not include 1.0, the result is statistically significant (B). For rare outcomes (uterine rupture is ~0.5–1% in TOLAC), the OR closely approximates the relative risk (C). The p-value is <0.05 but not exactly 0.05 (D is false — common misinterpretation). The attributable risk (E) cannot be determined from the OR alone — it requires the baseline risk in the control group.
Q191 [SBA] (Statistics) — A study examines the relationship between maternal BMI and birth weight in 5000 singleton term pregnancies. The Pearson correlation coefficient (r) between maternal BMI and birth weight is 0.18 (p < 0.001). Which of the following is the most appropriate interpretation? A) There is a strong positive linear relationship between BMI and birth weight B) There is a statistically significant but weak positive correlation between BMI and birth weight C) BMI explains 18% of the variation in birth weight D) A high BMI causes increased birth weight E) The correlation is not clinically meaningful because r < 0.5
Answer: B An r value of 0.18 indicates a weak positive correlation. With a large sample size (n=5000), even a weak correlation can be statistically significant (p < 0.001). The coefficient of determination R² = r² = 0.18² = 0.0324, meaning only ~3.2% (not 18%) of the variance in birth weight is explained by BMI (C and A are false). Correlation does not imply causation (D is false). Statistical significance and clinical meaningfulness are different concepts (E incorrectly dismisses it solely on r < 0.5).
Q192 [SBA] (Statistics) — A diagnostic test for fetal fibronectin (fFN) has a sensitivity of 80% and specificity of 90% for predicting preterm birth within 7 days in symptomatic women. If the positive predictive value (PPV) is 25%, what is the approximate prevalence of preterm birth within 7 days in this population? A) 1.5% B) 3.5% C) 6.5% D) 10.5% E) 25%
Answer: B Using Bayes' theorem and a 2×2 table approach: PPV = TP/(TP+FP) = 0.25. If sensitivity = 0.80 (TP = 0.80 × disease) and specificity = 0.90 (FP = 0.10 × no disease). Let prevalence = p. For 1000 women: Disease+ = 1000p, Disease− = 1000(1−p). TP = 800p, FN = 200p, TN = 900(1−p), FP = 100(1−p). PPV = 800p / [800p + 100(1−p)] = 0.25. Solve: 800p = 200p + 25(1−p) → 800p = 200p + 25 − 25p → 800p − 200p + 25p = 25 → 625p = 25 → p = 25/625 = 0.04 = 4%. Closest option is 3.5%.
More precisely: 800p / [800p + 100(1−p)] = 0.25 → 800p = 0.25(800p + 100 − 100p) = 0.25(700p + 100) = 175p + 25 → 800p − 175p = 25 → 625p = 25 → p = 0.04 = 4%. Given the options, 3.5% is the closest approximation. The exact prevalence is ~3.6–4%.
Q193 [MBA] (Statistics) — Which of the following statements regarding the CONSORT (Consolidated Standards of Reporting Trials) statement are TRUE? (Select all that apply.) A) CONSORT is a set of guidelines for reporting parallel-group randomised controlled trials B) It includes a 25-item checklist and a flow diagram C) Adherence to CONSORT is mandatory for all RCTs published in medical journals D) The flow diagram documents the number of participants at each stage of the trial E) CONSORT eliminates all sources of bias in clinical trials
Answer: A, B, D CONSORT is an evidence-based set of recommendations for reporting RCTs (A). It includes a 25-item checklist and a flow diagram (B). The flow diagram tracks participants through the stages: enrolment, allocation, follow-up, and analysis (D). While many journals endorse CONSORT and require compliance, it is not legally mandatory (C is false). CONSORT improves the quality of reporting but does not eliminate bias — it makes bias more transparent (E is false).
Q194 [SBA] (Statistics) — A diagnostic test for pre-eclampsia (soluble fms-like tyrosine kinase-1 / placental growth factor [sFlt-1/PlGF] ratio) has an area under the receiver operating characteristic (ROC) curve of 0.92 (95% CI 0.88–0.96). Which of the following is the correct interpretation of the area under the ROC curve (AUC)? A) The test correctly diagnoses pre-eclampsia in 92% of cases at all cut-off values B) There is a 92% probability that a randomly selected woman with pre-eclampsia will have a higher test result than a randomly selected woman without pre-eclampsia C) The optimal cut-off has a sensitivity of 92% and specificity of 92% D) 92% of the variation in test results is explained by the presence of pre-eclampsia E) The false positive rate is 8% at all cut-off values
Answer: B The AUC (or c-statistic) represents the probability that a randomly selected individual with the disease will have a higher test result than a randomly selected individual without the disease. An AUC of 0.92 indicates excellent discrimination. The AUC is not equivalent to "92% correct diagnoses" (A is false — it depends on the cut-off). The optimal cut-off maximises sensitivity and specificity but is not determined solely by the AUC (C is false). The AUC does not represent R² (D is false).
Q195 [SBA] (Statistics) — A crossover trial compares the analgesic efficacy of two treatments (drug A vs drug B) for dysmenorrhoea. Each woman receives both treatments in random order with a washout period. Which of the following is the main advantage of a crossover design over a parallel-group design? A) It eliminates the need for a washout period between treatments B) Each participant acts as their own control, reducing inter-subject variability and increasing statistical power C) It requires a larger sample size than a parallel-group design D) It can only be used for acute treatments with irreversible effects E) It eliminates the need for randomisation
Answer: B In a crossover trial, each participant receives both treatments and serves as their own control, which eliminates between-subject variability from the treatment comparison. This generally increases statistical power and allows a smaller sample size compared to a parallel-group design (C is false). However, crossover designs require a washout period to avoid carryover effects (A is false), are suitable only for chronic/stable conditions (not acute conditions with permanent effects — D is false), and still require randomisation of treatment order (E is false).
Q196 [MBA] (Statistics) — Which of the following statements about the Kaplan-Meier method for survival analysis are TRUE? (Select all that apply.) A) It provides a non-parametric estimate of the survival function B) It can handle censored data (loss to follow-up or event not yet occurred) C) The survival curve is a step function that changes only when an event occurs D) It assumes that censored individuals have the same probability of the event as those who remain under follow-up E) It requires the data to follow a normal distribution
Answer: A, B, C, D Kaplan-Meier is a non-parametric method (A — no assumption about the shape of the survival distribution). It handles censored data (B — the key advantage over other simple methods). The plot is a step function where each step down occurs at the time of an event (C). It assumes non-informative censoring: those censored have the same prognosis as those continuing (D). It does NOT require normal distribution (E is false — non-parametric methods have no distributional assumptions).
Q197 [SBA] (Clinical/Surgical) — A 28-year-old woman with a history of two previous caesarean sections presents in spontaneous labour at 39 weeks with a singleton cephalic fetus. She requests a trial of labour after caesarean (TOLAC). Which of the following is the strongest contraindication to TOLAC? A) Maternal BMI of 35 kg/m² B) Previous caesarean section was for breech presentation C) Interdelivery interval of 18 months D) Previous uterine incision was a classical (upper segment) caesarean section E) Gestational age of 39 weeks
Answer: D A previous classical (upper segment) caesarean section is a strong contraindication to TOLAC because of the significantly increased risk of uterine rupture (up to 4–9% compared to 0.5–1% for lower segment incisions). Other contraindications include: previous uterine rupture, more than 2 previous caesarean sections, and conditions that preclude vaginal delivery. Obesity (A) and short interdelivery interval (C) increase risk but are not absolute contraindications.
Q198 [MBA] (Clinical/Surgical) — Which of the following are recognised indications for performing an emergency peripartum hysterectomy? (Select all that apply.) A) Uncontrolled postpartum haemorrhage due to uterine atony unresponsive to medical therapy B) Morbidly adherent placenta (placenta accreta spectrum) with severe haemorrhage C) Extensive uterine rupture that cannot be repaired D) Postpartum haemorrhage due to retained products of conception E) Severe disseminated intravascular coagulation (DIC) unresponsive to blood product replacement
Answer: A, B, C Emergency peripartum hysterectomy is a life-saving procedure performed when conservative measures fail to control postpartum haemorrhage. The most common indications are: uterine atony unresponsive to medical treatment and uterine compression sutures (A), morbidly adherent placenta (placenta accreta/increta/percreta — B), and extensive uterine rupture (C). Retained products of conception (D) are managed by evacuation, not hysterectomy, unless complicated by infection or severe bleeding. DIC alone (E) is not an indication — the underlying cause of bleeding must be addressed.
Q199 [SBA] (Clinical/Surgical) — A 32-year-old woman with a BMI of 42 kg/m² is undergoing a caesarean section. The anaesthetist decides to perform the procedure under spinal anaesthesia rather than general anaesthesia. Which of the following best describes the advantages of regional anaesthesia over general anaesthesia in this patient? A) Regional anaesthesia eliminates the risk of aspiration pneumonia B) Spinal anaesthesia reduces the risk of failed intubation and aspiration in obese parturients C) Regional anaesthesia provides superior postoperative analgesia but increases the risk of venous thromboembolism D) Spinal anaesthesia is technically easier in obese patients than in non-obese patients E) Regional anaesthesia allows for immediate mobilisation after caesarean section
Answer: B The primary advantage of regional (neuraxial) anaesthesia over general anaesthesia in the obese parturient (BMI ≥40 kg/m²) is the avoidance of the risks associated with general anaesthesia: difficult/failed intubation (more common in obesity), aspiration of gastric contents, and airway complications. Obese pregnant women have higher rates of difficult airway and aspiration risk. Regional anaesthesia does not entirely eliminate aspiration risk (A) but avoids airway instrumentation. Spinal anaesthesia can be technically challenging in obesity (D is false).
Q200 [MBA] (Clinical/Surgical) — Which of the following perioperative interventions have been shown to reduce the risk of venous thromboembolism (VTE) in women undergoing major gynaecological surgery? (Select all that apply.) A) Early mobilisation postoperatively B) Intermittent pneumatic compression (IPC) devices C) Low molecular weight heparin (LMWH) prophylaxis D) Graduated compression stockings (GCS) alone E) Transexamic acid during surgery
Answer: A, B, C Early mobilisation (A) is a basic preventive measure. Intermittent pneumatic compression (B) and LMWH (C) are both well-established thromboprophylactic measures in gynaecological surgery, particularly in patients with additional risk factors (malignancy, obesity, age >60). Graduated compression stockings alone (D) have limited evidence as sole prophylaxis in moderate-to-high-risk surgery and are typically combined with other measures. Transexamic acid (E) is an antifibrinolytic that reduces bleeding but does NOT prevent VTE — it is a haemostatic agent.
Answer Key Summary
| Q | Type | Topic | Answer |
|---|---|---|---|
| 1 | SBA | Anatomy | D |
| 2 | SBA | Anatomy | B |
| 3 | MBA | Anatomy | A, B, D |
| 4 | SBA | Anatomy | B |
| 5 | SBA | Anatomy | B |
| 6 | MBA | Anatomy | A, B, C |
| 7 | SBA | Anatomy | B |
| 8 | SBA | Anatomy | B |
| 9 | SBA | Anatomy | C |
| 10 | SBA | Anatomy | C |
| 11 | MBA | Anatomy | A, B |
| 12 | SBA | Anatomy | C |
| 13 | SBA | Anatomy | B |
| 14 | SBA | Repro Phys | C |
| 15 | SBA | Repro Phys | B |
| 16 | MBA | Repro Phys | A, B, C |
| 17 | SBA | Repro Phys | A |
| 18 | SBA | Repro Phys | C |
| 19 | MBA | Repro Phys | A, B, D, E |
| 20 | SBA | Repro Phys | B |
| 21 | SBA | Repro Phys | B |
| 22 | SBA | Repro Phys | A |
| 23 | MBA | Repro Phys | A, B, C, D |
| 24 | SBA | Endocrinology | B |
| 25 | SBA | Endocrinology | B |
| 26 | MBA | Endocrinology | A, B, C, E |
| 27 | SBA | Endocrinology | C |
| 28 | SBA | Endocrinology | C |
| 29 | SBA | Endocrinology | B |
| 30 | MBA | Endocrinology | A, B, C, E |
| 31 | SBA | Endocrinology | B |
| 32 | SBA | Fetal/Neonatal | B |
| 33 | SBA | Fetal/Neonatal | B |
| 34 | MBA | Fetal/Neonatal | A, B, C |
| 35 | SBA | Fetal/Neonatal | A |
| 36 | SBA | Fetal/Neonatal | C |
| 37 | MBA | Fetal/Neonatal | A, B, C |
| 38 | SBA | Fetal/Neonatal | B |
| 39 | SBA | Fetal/Neonatal | B |
| 40 | SBA | Pathology | D |
| 41 | SBA | Pathology | C |
| 42 | MBA | Pathology | A, B, C, D |
| 43 | SBA | Pathology | B |
| 44 | SBA | Pathology | B |
| 45 | MBA | Pathology | A, B, C, E |
| 46 | SBA | Pathology | B |
| 47 | SBA | Pathology | C |
| 48 | SBA | Pathology | B |
| 49 | MBA | Pathology | A, B |
| 50 | SBA | Clinical/Surgical | B |
| 51 | SBA | Pharmacology | B |
| 52 | SBA | Pharmacology | B |
| 53 | MBA | Pharmacology | A, B, D |
| 54 | SBA | Pharmacology | C |
| 55 | MBA | Pharmacology | A, C |
| 56 | SBA | Pharmacology | A |
| 57 | SBA | Pharmacology | A |
| 58 | SBA | Pharmacology | B |
| 59 | MBA | Pharmacology | A, C, E |
| 60 | SBA | Pharmacology | C |
| 61 | SBA | Microbiology | B |
| 62 | MBA | Microbiology | A, C, D |
| 63 | SBA | Microbiology | B |
| 64 | SBA | Microbiology | B |
| 65 | SBA | Microbiology | C |
| 66 | MBA | Microbiology | B, D, E |
| 67 | SBA | Microbiology | B |
| 68 | SBA | Microbiology | C |
| 69 | SBA | Immunology | B |
| 70 | SBA | Immunology | B |
| 71 | MBA | Immunology | A, B, C, E |
| 72 | SBA | Immunology | B |
| 73 | SBA | Immunology | B |
| 74 | SBA | Biochemistry | A |
| 75 | MBA | Biochemistry | A, B, C, D |
| 76 | SBA | Biochemistry | B |
| 77 | SBA | Biochemistry | B |
| 78 | SBA | Biochemistry | B |
| 79 | MBA | Genetics | A, B, C |
| 80 | SBA | Genetics | B |
| 81 | SBA | Genetics | C |
| 82 | SBA | Genetics | B |
| 83 | MBA | Genetics | A, B, C |
| 84 | SBA | Embryology | A |
| 85 | SBA | Embryology | A |
| 86 | MBA | Embryology | A, B, C, D |
| 87 | SBA | Embryology | B |
| 88 | SBA | Embryology | A |
| 89 | SBA | Statistics | D |
| 90 | MBA | Statistics | A, B, C |
| 91 | SBA | Statistics | B |
| 92 | SBA | Statistics | B |
| 93 | MBA | Statistics | A, B, D |
| 94 | SBA | Statistics | B |
| 95 | SBA | Statistics | B |
| 96 | MBA | Statistics | A, B, C, D |
| 97 | SBA | Clinical/Surgical | D |
| 98 | MBA | Clinical/Surgical | A, B, C |
| 99 | SBA | Clinical/Surgical | B |
| 100 | MBA | Clinical/Surgical | A, B, C |