Mock Exam 13
MRCOG Part 1 — Mock Exam 13
Microbiology, Immunology, Clinical & Surgical Sciences, Fetal/Neonatal Physiology
100 Single Best Answer Questions with Answers and Explanations
📘 Q1 (Microbiology) — A 28-year-old primigravida at 36 weeks' gestation presents with a rash of small, red macules that rapidly progress to vesicles and pustules on an erythematous base. She has no prior history of this infection. Serology shows positive IgM antibodies. Which of the following is the most likely causative organism? A) Herpes simplex virus B) Varicella-zoster virus C) Coxsackie virus D) Parvovirus B19 E) Cytomegalovirus
Answer: B
Varicella-zoster virus (VZV) causes chickenpox. In pregnancy, primary VZV infection can cause significant maternal morbidity (pneumonitis) and fetal complications including congenital varicella syndrome (limb hypoplasia, skin scarring, microcephaly) if infection occurs in the first 20 weeks. IgM positivity indicates recent primary infection. HSV typically presents with vesicular lesions on mucosal surfaces, not a generalized maculopapular rash.
📘 Q2 (Microbiology) — A 32-year-old woman at 20 weeks' gestation has a routine antenatal screen that is positive for hepatitis B surface antigen (HBsAg). Her hepatitis B e antigen (HBeAg) is also positive. Which of the following is the most important intervention to reduce the risk of vertical transmission to the neonate? A) Elective caesarean section at term B) Hepatitis B immunoglobulin alone at birth C) Hepatitis B vaccine alone at birth D) Hepatitis B immunoglobulin plus vaccine within 12 hours of birth E) Maternal antiviral therapy with tenofovir in the third trimester
Answer: D
The standard of care to prevent perinatal HBV transmission is administration of hepatitis B immunoglobulin (HBIG) and the first dose of hepatitis B vaccine within 12 hours of birth, regardless of gestational age or mode of delivery. This combination is 85–95% effective at preventing transmission. Maternal antiviral therapy (tenofovir) in the third trimester is recommended for women with high viral load (>200,000 IU/mL) to reduce intrauterine transmission, but the most critical intervention at birth remains passive-active immunoprophylaxis.
📘 Q3 (Microbiology) — A 24-year-old woman presents with vaginal discharge, dysuria, and lower abdominal pain. On speculum examination, there is mucopurulent discharge from the cervix. Gram stain shows Gram-negative intracellular diplococci. Which of the following is the most appropriate first-line treatment in pregnancy? A) Azithromycin 1 g orally B) Ceftriaxone 500 mg intramuscularly C) Doxycycline 100 mg twice daily for 7 days D) Metronidazole 400 mg twice daily for 7 days E) Ciprofloxacin 500 mg orally
Answer: B
The Gram-negative intracellular diplococci indicate Neisseria gonorrhoeae. Ceftriaxone 500 mg IM is the first-line treatment for gonorrhoea in pregnancy. Doxycycline and ciprofloxacin are contraindicated in pregnancy. Azithromycin is used for Chlamydia trachomatis co-infection, which frequently occurs with gonorrhoea, but is not the primary treatment for gonococcal infection.
📘 Q4 (Microbiology) — A 30-year-old woman at 28 weeks' gestation presents with fever, malaise, and a rash described as "slapped cheek" appearance on her face. Her 3-year-old son had a similar illness 2 weeks ago. Which of the following is the greatest risk to the fetus? A) Congenital cataracts B) Sensorineural deafness C) Hydrops fetalis D) Microcephaly E) Limb hypoplasia
Answer: C
Parvovirus B19 causes erythema infectiosum (fifth disease). In pregnancy, transplacental infection can cause fetal anaemia due to the virus's tropism for erythroid progenitor cells, leading to high-output cardiac failure and hydrops fetalis. The risk is highest when infection occurs between 9–20 weeks' gestation. Congenital cataracts (rubella), sensorineural deafness (CMV, rubella), and microcephaly (CMV, toxoplasma, rubella) are not characteristic of parvovirus B19.
📘 Q5 (Microbiology) — A 26-year-old woman attends for her first antenatal visit at 12 weeks' gestation. Screening reveals she is rubella IgG negative. Which of the following is the most appropriate management? A) Administer MMR vaccine immediately B) Administer MMR vaccine after delivery C) Prescribe acyclovir prophylaxis D) Repeat rubella IgG at 28 weeks E) Advise termination of pregnancy
Answer: B
MMR (measles, mumps, rubella) vaccine is a live attenuated vaccine and is contraindicated during pregnancy. Rubella IgG-negative women should be counselled regarding avoidance of exposure and offered the MMR vaccine post-partum (preferably before discharge from hospital). Repeat IgG testing is not indicated. Acyclovir is for HSV, not rubella.
📘 Q6 (Microbiology) — On routine midstream urine culture at 16 weeks' gestation, a 29-year-old woman grows >10^5 CFU/mL of a Gram-negative rod. She is asymptomatic. Which of the following is the most appropriate management? A) No treatment needed as she is asymptomatic B) Nitrofurantoin 100 mg twice daily for 7 days C) Co-amoxiclav 625 mg three times daily for 3 days D) Observe and treat only if she develops symptoms E) Intravenous gentamicin
Answer: B
Asymptomatic bacteriuria occurs in 2–7% of pregnant women and, if untreated, progresses to pyelonephritis in 20–40% of cases, which is associated with preterm labour and low birth weight. The most common organism is Escherichia coli, a Gram-negative rod. Treatment is recommended for all pregnant women with asymptomatic bacteriuria. Nitrofurantoin is safe and effective in pregnancy (avoid at term due to risk of neonatal haemolysis). Co-amoxiclav is an alternative but shorter courses (3 days) may be less effective.
📘 Q7 (Microbiology) — A 31-year-old woman at 35 weeks' gestation is found to be GBS positive on rectovaginal swab screening. She has no risk factors for early-onset neonatal GBS disease. Which of the following is the most appropriate management? A) No intrapartum antibiotic prophylaxis B) Oral amoxicillin for 7 days C) Intrapartum intravenous benzylpenicillin D) Elective caesarean section E) Intrapartum intravenous gentamicin
Answer: C
Group B Streptococcus (GBS, Streptococcus agalactiae) is the leading cause of early-onset neonatal sepsis. Intrapartum antibiotic prophylaxis (IAP) with intravenous benzylpenicillin (or ampicillin) is recommended for all women with GBS-positive rectovaginal screening, regardless of risk factors. IAP significantly reduces vertical transmission from approximately 50% to 1–2%. Caesarean section is not indicated solely for GBS carriage.
📘 Q8 (Microbiology) — A 34-year-old woman presents with fever, rigors, and foul-smelling lochia 5 days after an emergency caesarean section. On examination, her temperature is 39.2°C, pulse 110 bpm, and there is marked uterine tenderness. Which of the following is the most likely causative organism? A) Staphylococcus aureus B) Streptococcus agalactiae C) Escherichia coli D) Bacteroides fragilis E) Chlamydia trachomatis
Answer: D
Puerperal sepsis following caesarean section is typically polymicrobial, involving anaerobes such as Bacteroides fragilis, along with aerobic Gram-negative rods (E. coli) and Gram-positive cocci. B. fragilis is a prominent anaerobic component of the vaginal and gastrointestinal flora that commonly causes endometritis post-caesarean. The presentation with foul-smelling lochia is characteristic of anaerobic infection. Chlamydia is an important cause but more typically associated with subacute or late-onset postpartum infection.
📘 Q9 (Microbiology) — A 22-year-old woman presents with vaginal itching, a white curd-like discharge, and vulval erythema. A high vaginal swab shows pseudohyphae on microscopy. She is 18 weeks pregnant. Which of the following is the most appropriate treatment? A) Oral fluconazole 150 mg single dose B) Clotrimazole 500 mg pessary single dose C) Metronidazole 400 mg twice daily for 7 days D) Oral itraconazole 200 mg daily for 7 days E) No treatment as it is self-limiting
Answer: B
The presentation is typical of vulvovaginal candidiasis (Candida albicans). In pregnancy, topical azoles (clotrimazole, miconazole) are the treatment of choice. Oral fluconazole is relatively contraindicated in pregnancy, especially in the first trimester, due to associations with miscarriage and congenital anomalies (particularly cardiac defects) at high doses. Metronidazole is for bacterial vaginosis and trichomoniasis, not candidiasis.
📘 Q10 (Microbiology) — A 27-year-old woman at 10 weeks' gestation has a routine serology screen. She is found to be Toxoplasma IgG positive but IgM negative. Which of the following is the most accurate interpretation? A) She has an acute Toxoplasma infection requiring treatment B) She has had past infection and is immune C) She has a reactivation of latent Toxoplasma D) She needs amniocentesis for PCR testing E) She requires spiramycin prophylaxis
Answer: B
Toxoplasma-specific IgG with negative IgM indicates past infection and immunity. Acute infection is characterized by positive IgM (with or without IgG seroconversion). In immunocompetent individuals, primary infection confers lifelong immunity. Reactivation does not typically occur in immunocompetent pregnant women. Amniocentesis for PCR and spiramycin are indicated only in cases of suspected acute infection acquired during pregnancy.
📘 Q11 (Microbiology) — A 33-year-old woman at 32 weeks' gestation presents with genital ulcers that are painful, shallow, and have an erythematous base. She reports a similar episode 6 months ago. Which of the following is the most likely diagnosis? A) Primary syphilis B) Chancroid C) Genital herpes simplex virus infection D) Lymphogranuloma venereum E) Fixed drug eruption
Answer: C
Recurrent painful genital ulcers are characteristic of genital herpes simplex virus (HSV) infection. Primary syphilis (chancre) presents as a painless, indurated ulcer. Chancroid (Haemophilus ducreyi) causes painful ulcers but is less common and typically not recurrent in the same pattern. The history of a similar prior episode strongly favours HSV reactivation. In pregnancy, recurrent HSV is less risky to the neonate than primary infection, but suppressive acyclovir from 36 weeks is often recommended.
📘 Q12 (Microbiology) — A 25-year-old woman is diagnosed with primary syphilis at 16 weeks' gestation. She has no known drug allergies. Which of the following is the most appropriate treatment? A) Oral erythromycin 500 mg four times daily for 14 days B) Benzathine penicillin G 2.4 million units IM single dose C) Intravenous ceftriaxone 1 g daily for 10 days D) Doxycycline 100 mg twice daily for 14 days E) Azithromycin 2 g orally single dose
Answer: B
Benzathine penicillin G (2.4 million units IM) is the treatment of choice for primary, secondary, and early latent syphilis in pregnancy. Penicillin is the only agent proven to prevent congenital syphilis. Doxycycline is contraindicated in pregnancy. Erythromycin and azithromycin do not reliably cross the placenta to treat fetal infection. In penicillin-allergic patients, desensitization followed by penicillin is recommended.
📘 Q13 (Microbiology) — A 35-year-old woman at 22 weeks' gestation presents with a painless, non-pruritic maculopapular rash on her trunk and palms. She also has generalized lymphadenopathy and condylomata lata. Serology is VDRL positive with a titre of 1:32. Which of the following is the most likely stage of infection? A) Primary syphilis B) Secondary syphilis C) Latent syphilis D) Tertiary syphilis E) Neurosyphilis
Answer: B
Secondary syphilis occurs 4–10 weeks after the primary chancre and is characterized by a generalized maculopapular rash (often involving the palms and soles), condylomata lata (moist, wart-like lesions), lymphadenopathy, fever, and malaise. VDRL titre is typically ≥1:16 in secondary syphilis. The risk of congenital syphilis is very high at this stage if untreated. Treatment is benzathine penicillin G 2.4 million units IM, with some guidelines recommending a second dose 1 week later in pregnancy.
📘 Q14 (Microbiology) — A 28-year-old G2P1 woman at 38 weeks' gestation presents with preterm prelabour rupture of membranes (PPROM) of 18 hours duration. She has a temperature of 38.5°C and fetal tachycardia (170 bpm). Which of the following organisms is most likely responsible for ascending infection? A) Staphylococcus epidermidis B) Ureaplasma urealyticum C) Gardnerella vaginalis D) Group A Streptococcus E) Lactobacillus crispatus
Answer: C
Bacterial vaginosis (BV)-associated organisms, particularly Gardnerella vaginalis, are commonly implicated in ascending infection leading to PPROM and chorioamnionitis. The normal vaginal flora (Lactobacillus species) protects against ascending infection; disruption of this microbiome (as in BV) increases risk. Ureaplasma is also associated with PPROM but Gardnerella is the most characteristic BV organism. Group A Streptococcus causes severe sepsis but is less common overall.
📘 Q15 (Microbiology) — A 22-year-old woman presents with lower abdominal pain, dyspareunia, and abnormal vaginal bleeding. On examination, there is cervical excitation. She uses an intrauterine device (IUD) for contraception. An endocervical swab is positive for Chlamydia trachomatis. Which of the following is the most important additional investigation? A) HIV testing B) Ultrasound of pelvis C) Test for N. gonorrhoeae D) Laparoscopy E) Hysterosalpingography
Answer: C
Chlamydia trachomatis and Neisseria gonorrhoeae frequently co-exist (co-infection rate 30–50%). Testing for gonorrhoea is essential before treatment. The clinical picture (lower abdominal pain, cervical excitation) suggests pelvic inflammatory disease (PID). The IUD should be removed after starting treatment. HIV testing is also recommended in any patient diagnosed with an STI, but in the immediate context, testing for concurrent gonorrhoea is the most critical next step as it alters antibiotic choice.
📘 Q16 (Microbiology) — A 40-year-old woman with known HIV (CD4 count 180 cells/μL, viral load 50,000 copies/mL) presents at 34 weeks' gestation. She is not currently on antiretroviral therapy. Which of the following is the most important intervention to reduce mother-to-child transmission (MTCT)? A) Elective caesarean section at 38 weeks B) Start zidovudine monotherapy C) Start combination antiretroviral therapy immediately D) Vaginal delivery with intrapartum nevirapine E) Avoid breastfeeding
Answer: C
Combination antiretroviral therapy (cART) is the cornerstone of prevention of MTCT of HIV. With a CD4 <200 and high viral load, immediate initiation of cART is critical to suppress viral replication. The viral load at delivery is the strongest predictor of MTCT. With viral suppression <50 copies/mL, vaginal delivery is possible. Without suppression, elective caesarean section at 38 weeks is recommended. Zidovudine monotherapy is inadequate; breastfeeding avoidance alone is insufficient.
📘 Q17 (Microbiology) — Routine antenatal screening at 12 weeks shows a 28-year-old woman is hepatitis C antibody positive. Confirmatory HCV RNA is detected. Which of the following is the most accurate statement regarding vertical transmission? A) Transmission occurs in 40–50% of pregnancies B) Transmission occurs in approximately 5% of pregnancies C) Transmission is prevented by caesarean section D) Breastfeeding is contraindicated E) Antiviral therapy in pregnancy is routinely recommended
Answer: B
Vertical transmission of Hepatitis C occurs in approximately 5% (range 3–10%) of pregnancies. Higher rates are associated with maternal HIV co-infection and high viral load. Elective caesarean section does not reduce transmission, nor is breastfeeding contraindicated unless nipples are cracked/bleeding. Direct-acting antiviral (DAA) therapy is not yet routinely recommended in pregnancy due to limited safety data, though trials are ongoing.
📘 Q18 (Microbiology) — A 34-year-old woman at 14 weeks' gestation has a primary infection with cytomegalovirus (CMV). She is very anxious about fetal effects. Which of the following is the most common long-term sequelae in congenitally infected infants? A) Hydrops fetalis B) Congenital heart disease C) Sensorineural hearing loss D) Cleft palate E) Limb reduction defects
Answer: C
Congenital CMV is the leading non-genetic cause of sensorineural hearing loss in children. Approximately 10–15% of congenitally infected infants will have symptomatic disease at birth, and among asymptomatic infants, 10–15% will develop late sequelae, most commonly hearing loss. Other manifestations include microcephaly, intracranial calcifications, chorioretinitis, and developmental delay. Hydrops fetalis is associated with parvovirus B19. Limb defects are associated with varicella.
📘 Q19 (Microbiology) — A 29-year-old woman presents with vaginal discharge and itching. On wet mount microscopy, motile flagellated protozoa are seen. Which of the following is the most appropriate treatment in pregnancy? A) Clotrimazole pessary B) Metronidazole 400 mg twice daily for 7 days C) Tinidazole 2 g single dose D) Doxycycline 100 mg twice daily for 7 days E) No treatment as it is asymptomatic
Answer: B
Trichomonas vaginalis is a flagellated protozoan causing vaginitis. Metronidazole is safe and effective in pregnancy (all trimesters) and is the treatment of choice. Tinidazole has less safety data in pregnancy. Although BV treatment guidelines allow topical clindamycin, trichomoniasis requires systemic therapy to eradicate the organism from all sites. Treatment of pregnant women reduces the risk of preterm delivery and vertical transmission.
📘 Q20 (Microbiology) — A 36-year-old woman at 30 weeks' gestation presents with a 2-week history of low-grade fever, myalgia, and a rash described as erythema chronicum migrans. She lives in a rural area and has a dog. Which of the following is the most likely diagnosis? A) Rocky Mountain spotted fever B) Lyme disease C) Leptospirosis D) Toxoplasmosis E) Syphilis
Answer: B
Erythema chronicum migrans (bull's-eye rash) is pathognomonic for Lyme disease caused by Borrelia burgdorferi, transmitted by Ixodes ticks. Pregnant women with Lyme disease should be treated (amoxicillin or cefuroxime; doxycycline is contraindicated) to prevent transplacental transmission, though adverse fetal outcomes are rare. Toxoplasmosis is from cats/undercooked meat. Leptospirosis presents with fever and jaundice, not this rash.
📘 Q21 (Microbiology) — A 28-year-old woman with sickle cell disease presents at 32 weeks' gestation with fever, headache, and arthralgia. She returned from a trip to Nigeria 1 week ago. Blood film shows ring forms within red blood cells. Which of the following is the most appropriate management? A) Chloroquine B) Artemether-lumefantrine C) Proguanil D) Intravenous quinidine E) Doxycycline
Answer: B
The presentation is consistent with malaria (Plasmodium falciparum in a patient from Nigeria). Artemether-lumefantrine is the recommended first-line treatment for uncomplicated malaria in the second and third trimesters of pregnancy. Pregnant women are at increased risk of severe malaria. Chloroquine resistance is widespread. Intravenous artesunate (not quinidine) is for severe malaria. Pregnant women with sickle cell disease are at particularly high risk of complications.
📘 Q22 (Microbiology) — During a caesarean section, a 32-year-old woman develops a temperature of 38.5°C on the second post-operative day. The wound appears erythematous and has purulent discharge. A wound swab grows Gram-positive cocci in clusters that are coagulase-positive. Which of the following is the most likely organism? A) Streptococcus pyogenes B) Staphylococcus aureus C) Staphylococcus epidermidis D) Enterococcus faecalis E) Pseudomonas aeruginosa
Answer: B
Gram-positive cocci in clusters that are coagulase-positive is characteristic of Staphylococcus aureus, the most common cause of surgical site infections (SSIs). S. aureus produces coagulase, distinguishing it from S. epidermidis (coagulase-negative). MRSA (methicillin-resistant S. aureus) is an important consideration. S. pyogenes is Gram-positive cocci in chains. Pseudomonas is Gram-negative.
📘 Q23 (Microbiology) — A 26-year-old primigravida has a screening vaginal swab at 36 weeks that shows normal lactobacillus-dominated flora. She has no symptoms. Which of the following statements regarding the vaginal microbiome in pregnancy is most accurate? A) Lactobacillus dominance is associated with increased risk of preterm birth B) A diverse microbiome with reduced Lactobacillus is normal in pregnancy C) Lactobacillus dominance is protective against ascending infection D) The vaginal microbiome does not change throughout pregnancy E) Lactobacillus species produce alkaline pH
Answer: C
A healthy vaginal microbiome in pregnancy is dominated by Lactobacillus species, which produce lactic acid and hydrogen peroxide, maintaining an acidic pH (3.8–4.2). This environment inhibits the growth of pathogenic organisms and protects against ascending infection. Disruption of this balance (bacterial vaginosis) is associated with preterm birth, PPROM, and ascending infection. The vaginal microbiome typically becomes more Lactobacillus-dominated as pregnancy progresses.
📘 Q24 (Microbiology) — A 33-year-old woman at 8 weeks' gestation has primary genital HSV infection. Which of the following is the most accurate regarding fetal risk? A) There is no risk to the fetus B) There is a high risk of congenital anomalies C) There is an increased risk of miscarriage D) Neonatal HSV is most likely to be acquired during vaginal delivery E) Oral acyclovir reduces the risk of neonatal HSV
Answer: D
Neonatal HSV is most commonly acquired during passage through an infected birth canal (intrapartum transmission), with the highest risk (30–50%) in women who acquire primary HSV infection in the third trimester. Primary infection in the first trimester is associated with an increased miscarriage risk, but not typically congenital anomalies (unlike rubella/CMV). Acyclovir can reduce viral shedding and lesion duration but has not been proven to reduce neonatal transmission in primary infection.
📘 Q25 (Microbiology) — A 30-year-old woman presents with a painless ulcer on her labia 3 weeks after a new sexual partner. On examination, there is a single, indurated, clean-based ulcer with firm, non-tender inguinal lymphadenopathy. Dark-field microscopy of the ulcer exudate shows spirochaetes. Which of the following is the most likely diagnosis? A) Genital herpes B) Primary syphilis C) Chancroid D) Lymphogranuloma venereum E) Granuloma inguinale
Answer: B
The painless, indurated (hard) ulcer (chancre) with non-tender lymphadenopathy plus spiral-shaped organisms on dark-field microscopy is diagnostic of primary syphilis (Treponema pallidum). The incubation period is 9–90 days (average 21 days). Genital herpes causes painful vesicles/ulcers. Chancroid causes painful, non-indurated ulcers with tender lymphadenopathy. LGV presents with painless papule followed by painful lymphadenopathy.
📘 Q26 (Immunology) — Which immunoglobulin is primarily responsible for mediating the acute allergic response and is bound by mast cells via high-affinity Fc receptors? A) IgA B) IgD C) IgE D) IgG E) IgM
Answer: C
IgE is the immunoglobulin isotype responsible for type I hypersensitivity reactions. It binds to high-affinity Fcε receptors on mast cells and basophils. Cross-linking of surface-bound IgE by allergen triggers degranulation and release of histamine, leukotrienes, and other inflammatory mediators. IgE levels are elevated in atopic individuals and in parasitic infections. IgG is the most abundant serum immunoglobulin and mediates opsonization and neutralization.
📘 Q27 (Immunology) — A 30-year-old woman with systemic lupus erythematosus (SLE) becomes pregnant. Which of the following autoantibodies is most strongly associated with the risk of fetal heart block? A) Anti-double-stranded DNA B) Anti-Ro (SSA) and anti-La (SSB) C) Anticardiolipin antibodies D) Anti-Sm E) Anti-RNP
Answer: B
Anti-Ro (SSA) and anti-La (SSB) antibodies cross the placenta and can bind to fetal cardiac conduction tissue, causing inflammation and fibrosis of the atrioventricular node, leading to congenital heart block (typically third-degree block). This occurs in approximately 2% of pregnancies of anti-Ro-positive women, with a recurrence risk of 15–20% in subsequent pregnancies. Anticardiolipin antibodies are associated with recurrent pregnancy loss and thrombosis, not heart block.
📘 Q28 (Immunology) — Which of the following best describes the function of regulatory T cells (Tregs) in pregnancy? A) They promote rejection of the semi-allogeneic fetus B) They suppress maternal immune responses against fetal antigens C) They produce IFN-γ to activate natural killer cells D) They are increased in pre-eclampsia E) They are the primary antigen-presenting cells at the decidua
Answer: B
Regulatory T cells (Tregs, CD4+CD25+FoxP3+) play a critical role in maternal-fetal tolerance by suppressing effector T cell responses against paternally-derived fetal antigens. Tregs expand during normal pregnancy and their number and function are reduced in conditions such as miscarriage, pre-eclampsia, and preterm labour. They act through secretion of IL-10 and TGF-β and via cell-contact-dependent suppression. Decidual NK cells, not Tregs, are the predominant lymphocytes at the implantation site.
📘 Q29 (Immunology) — A 28-year-old RhD-negative primigravida delivers an RhD-positive baby. She did not receive anti-D prophylaxis. She is now 30 weeks pregnant with her second child. Indirect Coombs test is positive at a titre of 1:32. Which of the following is the most likely pathophysiology? A) Maternal IgM antibodies crossing the placenta B) Maternal IgG anti-D antibodies causing fetal haemolysis C) Fetal red cells crossing into maternal circulation causing maternal anaemia D) Complement-mediated lysis of maternal red cells E) Type II hypersensitivity reaction against maternal platelets
Answer: B
RhD alloimmunization occurs when fetal RhD-positive red cells enter the maternal circulation of an RhD-negative woman, stimulating production of IgG anti-D antibodies. In subsequent pregnancies, these IgG antibodies (the only Ig isotype that crosses the placenta via FcRn) cause haemolytic disease of the fetus and newborn (HDFN) by opsonizing fetal red cells for destruction (type II hypersensitivity). IgM antibodies do not cross the placenta. A positive Indirect Coombs test detects maternal IgG anti-D antibodies.
📘 Q30 (Immunology) — Which of the following components of the innate immune system is most important in the first-line defence against pathogens in the female genital tract? A) Neutrophils B) Natural killer cells C) Antimicrobial peptides (defensins) D) Complement proteins E) Dendritic cells
Answer: C
Antimicrobial peptides (AMPs), including defensins and cathelicidins, are produced by epithelial cells of the female genital tract and provide a crucial first-line chemical defence against bacterial, viral, and fungal pathogens. They are constitutively expressed and upregulated in response to infection. Neutrophils and NK cells are important but are recruited after the initial epithelial barrier and AMP defences. The cervical mucus plug in pregnancy is rich in AMPs.
📘 Q31 (Immunology) — In the context of transplantation immunology, a patient who had a kidney transplant 10 years ago is now pregnant. Which of the following best describes HLA-G? A) It is expressed on all nucleated cells and presents viral antigens B) It is a classical MHC class I molecule that stimulates T cell responses C) It is a non-classical MHC class I molecule expressed at the maternal-fetal interface that inhibits NK cell activity D) It is an MHC class II molecule expressed on decidual dendritic cells E) It is responsible for presenting lipid antigens to NKT cells
Answer: C
HLA-G is a non-classical MHC class I molecule (class Ib) that is selectively expressed on extravillous trophoblast cells at the maternal-fetal interface. Its primary function is to inhibit maternal NK cell cytotoxicity by binding to KIR receptors (KIR2DL4) and to induce immunosuppressive Treg responses. This protects the fetus from maternal immune attack. Unlike classical MHC class I (HLA-A, -B, -C), HLA-G has limited polymorphism and does not present antigen to T cells in the conventional manner.
📘 Q32 (Immunology) — A 26-year-old woman presents with recurrent miscarriage. She is found to have antiphospholipid syndrome (APS). Which of the following describes the mechanism by which antiphospholipid antibodies cause pregnancy loss? A) They directly damage fetal red blood cells B) They activate complement at the trophoblast surface, causing inflammation and thrombosis C) They inhibit IL-2 production by T cells D) They block progesterone receptors on the decidua E) They cause maternal neutropenia
Answer: B
Antiphospholipid antibodies (aPL) bind to β2-glycoprotein I on the trophoblast surface, activating complement via the classical pathway. This triggers an inflammatory cascade leading to neutrophil infiltration, tissue factor activation, and a prothrombotic state, ultimately causing placental thrombosis, infarction, and pregnancy loss. The standard treatment is low-dose aspirin plus low molecular weight heparin. aPL also inhibit trophoblast proliferation and syncytialization.
📘 Q33 (Immunology) — Which of the following cytokines is most critical for the differentiation of Th17 cells, a subset implicated in several autoimmune diseases and in the pathogenesis of preterm labour? A) IL-12 B) IL-4 C) TGF-β and IL-6 D) IL-2 E) IFN-γ
Answer: C
Th17 cell differentiation requires the combination of TGF-β and IL-6. Th17 cells produce IL-17A, IL-17F, and IL-22, which recruit neutrophils and promote inflammation. They are implicated in autoimmune diseases (psoriasis, rheumatoid arthritis, multiple sclerosis) and in the inflammatory milieu of preterm labour and chorioamnionitis. IL-12 drives Th1 differentiation, IL-4 drives Th2 differentiation, and IL-2 promotes T cell proliferation.
📘 Q34 (Immunology) — A 35-year-old woman with rheumatoid arthritis (RA) is planning pregnancy. Her RA is well-controlled on adalimumab (a TNF-alpha inhibitor). Which of the following is the most accurate statement regarding TNF-alpha inhibitors in pregnancy? A) They are absolutely contraindicated in pregnancy B) They are generally considered safe in the first and second trimesters but should be stopped in the third trimester to minimize placental transfer C) They cause high rates of congenital anomalies D) They are only safe in the third trimester E) They must be stopped 6 months before conception
Answer: B
TNF-alpha inhibitors (adalimumab, infliximab, etanercept) are IgG1 monoclonal antibodies that are actively transported across the placenta via FcRn, primarily in the third trimester. They are generally considered low risk in early pregnancy and can be continued until around 20 weeks' gestation. Stopping in the third trimester reduces fetal drug exposure. They are not associated with a significant increase in congenital anomalies above baseline. The decision involves balancing maternal disease control with fetal exposure.
📘 Q35 (Immunology) — Which of the following best describes the role of natural killer (NK) cells at the maternal-fetal interface? A) They are cytotoxic and attack fetal trophoblast cells B) They are decidual NK cells (CD56bright CD16−) that secrete cytokines to promote spiral artery remodelling C) They are identical to peripheral blood NK cells D) They produce large amounts of perforin and granzyme B E) They reject the fetus in cases of recurrent miscarriage
Answer: B
Decidual NK (dNK) cells are phenotypically distinct from peripheral NK cells — they are CD56bright and CD16− (peripheral NK cells are CD56dim CD16+). Instead of being cytotoxic, dNK cells secrete angiogenic factors (VEGF, PlGF) and cytokines (IFN-γ, IL-8) that are critical for spiral artery remodelling and placentation. Dysfunctional dNK cells are implicated in pre-eclampsia, fetal growth restriction, and recurrent miscarriage. They interact with trophoblast HLA-C and HLA-G via KIR receptors.
📘 Q36 (Immunology) — A 32-year-old woman with Hashimoto's thyroiditis (autoimmune hypothyroidism) is euthyroid on levothyroxine at 14 weeks' gestation. Which of the following is the most accurate regarding autoimmune thyroid disease in pregnancy? A) Pregnancy typically worsens autoimmune thyroid disease B) Levothyroxine requirements usually decrease in the first trimester C) Thyroid autoantibodies (TPO) cross the placenta and cause fetal goitre D) Levothyroxine dose often needs to increase by 30–50% in pregnancy E) Fetal TSH is independent of maternal T4 levels
Answer: D
In pregnancy, oestrogen increases thyroxine-binding globulin (TBG), and the placenta deiodinates maternal T4. Levothyroxine requirements typically increase by 30–50% from baseline, often as early as 4–6 weeks' gestation. TSH should be monitored every 4–6 weeks and dose adjusted to maintain TSH <2.5 mIU/L in the first trimester and <3.0 mIU/L in later trimesters. Thyroid autoantibodies (anti-TPO, anti-thyroglobulin) can cross the placenta but cause fetal/neonatal thyroid dysfunction only rarely.
📘 Q37 (Immunology) — Which immunoglobulin isotype is most abundant in mucosal secretions such as cervical mucus and breast milk? A) IgA B) IgD C) IgE D) IgG E) IgM
Answer: A
Secretory IgA (sIgA) is the predominant immunoglobulin in mucosal secretions, including cervical mucus, breast milk (especially colostrum), saliva, and gastrointestinal fluids. It is a dimer linked by a J-chain and complexed with secretory component, which protects it from proteolytic degradation. sIgA provides immune exclusion by agglutinating pathogens and preventing their attachment to mucosal surfaces. Breast milk sIgA provides passive mucosal protection to the nursing infant.
📘 Q38 (Immunology) — A 34-year-old woman at 25 weeks' gestation develops severe pre-eclampsia. Which of the following immunological mechanisms is most strongly implicated in the pathogenesis of pre-eclampsia? A) Excessive Th2 bias B) Impaired trophoblast invasion and inadequate spiral artery remodelling due to altered NK cell–trophoblast interaction C) Overactivity of regulatory T cells D) Excessive complement inhibition E) Type I hypersensitivity to fetal antigens
Answer: B
Pre-eclampsia is associated with inadequate trophoblast invasion and failure of spiral artery remodelling, leading to placental ischaemia. This is linked to altered interactions between decidual NK cell KIR receptors and trophoblast HLA-C molecules. Specifically, certain maternal KIR genotypes (AA) combined with fetal HLA-C2 alleles increase risk. The resulting placental hypoxia releases factors (sFlt-1, sEng) that cause maternal endothelial dysfunction and hypertension. Excessive Th1 cytokines also contribute.
📘 Q39 (Immunology) — Which of the following is the most accurate description of the classical pathway of complement activation? A) It is activated by mannose-binding lectin binding to pathogen surfaces B) It is activated by C3b binding to microbial surfaces C) It is activated by antigen-antibody complexes (IgM or IgG) D) It is activated by bacterial lipopolysaccharide E) It is activated by factor D
Answer: C
The classical complement pathway is initiated when C1q binds to the Fc region of antigen-bound IgM or IgG antibodies. This activates C1r and C1s, which cleave C4 and C2 to form the C3 convertase (C4b2a). The lectin pathway is activated by mannose-binding lectin binding to microbial carbohydrates. The alternative pathway is activated by spontaneous hydrolysis of C3 (C3b) on microbial surfaces, amplified by factors B, D, and properdin.
📘 Q40 (Immunology) — A 27-year-old woman is found to have a low CD4 count on routine testing. She has no history of opportunistic infections. Which of the following best describes the primary function of CD4+ T cells? A) Direct killing of virus-infected cells B) Antibody production C) Helper function — they recognize antigen on MHC class II and provide co-stimulation to B cells and CD8+ T cells D) Antigen presentation to naïve T cells E) Production of complement proteins
Answer: C
CD4+ T helper (Th) cells are the "orchestrators" of adaptive immunity. They recognize peptide antigens presented on MHC class II molecules by antigen-presenting cells (APCs). They provide essential help to B cells (for antibody production and class switching) and to CD8+ cytotoxic T cells (for optimal activation). They also secrete cytokines that shape the type of immune response (Th1, Th2, Th17, Treg). CD8+ T cells kill infected cells. B cells produce antibodies.
📘 Q41 (Immunology) — A 31-year-old woman with immune thrombocytopenic purpura (ITP) is pregnant at 28 weeks. Her platelet count is 45 × 10^9/L. Which of the following is the most appropriate management? A) Intravenous immunoglobulin (IVIG) B) Platelet transfusion C) Splenectomy D) Rituximab E) Azathioprine
Answer: A
ITP in pregnancy is managed with corticosteroids (prednisolone) as first line, with IVIG as second line or for rapid count elevation before delivery. IVIG works by blocking Fc receptors on macrophages, reducing platelet destruction. Platelet transfusion is reserved for active bleeding or before caesarean section with very low counts. Splenectomy is avoided in pregnancy if possible. Rituximab has limited safety data in pregnancy. The goal is a platelet count >50 × 10^9/L for vaginal delivery or >80 × 10^9/L for caesarean.
📘 Q42 (Immunology) — Which of the following best describes the process of T cell receptor (TCR) recognition of antigen? A) The TCR recognizes native protein antigens directly B) The TCR recognizes peptide fragments bound to MHC molecules C) The TCR recognizes carbohydrate antigens D) The TCR recognizes lipid antigens presented by CD1 E) The TCR binds to free antigen in solution
Answer: B
The αβ T cell receptor (TCR) recognizes peptide fragments (8–10 amino acids for MHC class I, 12–20 for MHC class II) that are bound in the groove of MHC molecules on the surface of antigen-presenting cells. This is known as MHC restriction. Unlike B cell receptors (antibodies) that recognize native/conformational antigens, TCRs cannot bind free antigen. NKT cells recognize lipid antigens via CD1d, but this is not the main T cell population.
📘 Q43 (Immunology) — A 29-year-old woman has a history of two first-trimester miscarriages. She is found to have elevated natural killer cell activity on peripheral blood testing. Which of the following is the most evidence-based intervention for her next pregnancy? A) Prednisolone 20 mg daily B) Intralipid infusions C) IVIG D) No proven effective intervention — the evidence for immunomodulation in this context is limited E) TNF-alpha inhibitors
Answer: D
Despite the popularity of "immune testing" in recurrent miscarriage, there is no robust evidence that peripheral NK cell testing or immunomodulatory treatments (prednisolone, IVIG, intralipid, TNF inhibitors) improve live birth rates in women with elevated NK cell activity. The RCOL and ASRM guidelines emphasize that such treatments should only be offered in research settings. The mainstay of recurrent miscarriage management remains investigation for antiphospholipid syndrome, anatomical, genetic, and endocrine causes.
📘 Q44 (Immunology) — Which of the following cell types is the most efficient antigen-presenting cell (APC) for activating naïve T cells? A) B cell B) Macrophage C) Dendritic cell D) Neutrophil E) Natural killer cell
Answer: C
Dendritic cells (DCs) are the most potent professional antigen-presenting cells, uniquely capable of activating naïve T cells. They capture antigens in peripheral tissues, migrate to lymph nodes, and present processed peptides on MHC molecules along with co-stimulatory signals (CD80/86) and cytokines. Macrophages and B cells can present antigen to already-primed T cells but are less effective at priming naïve T cells. Neutrophils and NK cells are not professional APCs.
📘 Q45 (Immunology) — A 33-year-old woman at 20 weeks' gestation develops severe herpes zoster (shingles) affecting the T10 dermatome. She is immunocompetent. Which of the following is the most appropriate management? A) Intravenous acyclovir B) Oral acyclovir C) Varicella-zoster immunoglobulin D) No treatment — supportive care only E) Oral famciclovir
Answer: B
Herpes zoster (shingles) results from reactivation of latent VZV in dorsal root ganglia. In immunocompetent pregnant women, oral acyclovir (or valacyclovir) is indicated to reduce pain, accelerate healing, and reduce the risk of post-herpetic neuralgia. There is no risk of congenital varicella syndrome from shingles (maternal antibodies are already present). IV acyclovir is reserved for disseminated disease or immunocompromised patients. VZIG is for post-exposure prophylaxis in susceptible individuals.
📘 Q46 (Immunology) — Which of the following statements about IgG subclasses is most accurate? A) IgG1 and IgG3 cross the placenta most efficiently B) IgG2 is the predominant subclass in antibody responses to protein antigens C) IgG4 deficiency is the most common IgG subclass deficiency D) IgG3 has the shortest half-life and is the most abundant subclass E) All IgG subclasses equally activate complement
Answer: A
IgG1 and IgG3 cross the placenta most efficiently via neonatal Fc receptor (FcRn) transport. IgG2 has poor placental transfer and responds primarily to polysaccharide antigens. IgG4 has unique anti-inflammatory properties and does not fix complement. IgG1 is the most abundant subclass (60–70%). IgG3 has the shortest half-life (~7 days vs ~21 days for other subclasses) and is highly efficient at complement activation. Understanding subclass placental transfer is crucial for HDFN risk assessment.
📘 Q47 (Immunology) — A 25-year-old woman presents with anaphylaxis after receiving intravenous iron for postpartum anaemia. Which immunoglobulin isotype mediates this reaction? A) IgA B) IgD C) IgE D) IgG E) IgM
Answer: C
Anaphylaxis is a type I hypersensitivity reaction mediated by IgE antibodies. Prior sensitization leads to IgE production and binding to FcεRI on mast cells and basophils. Re-exposure cross-links surface IgE, triggering degranulation and release of histamine, tryptase, leukotrienes, and prostaglandins. This causes bronchospasm, laryngeal oedema, hypotension, and urticaria. Treatment is intramuscular adrenaline. IgG-mediated anaphylactoid reactions can also occur (type II/III) but are less common.
📘 Q48 (Immunology) — Which cytokine is produced by trophoblasts and has been shown to promote a Th2-biased immune response at the maternal-fetal interface, contributing to pregnancy maintenance? A) IFN-γ B) IL-12 C) IL-10 D) TNF-α E) IL-2
Answer: C
IL-10 is a potent anti-inflammatory cytokine produced by trophoblasts, decidual macrophages, and regulatory T cells at the maternal-fetal interface. It suppresses Th1 responses (which produce pro-inflammatory cytokines like IFN-γ and TNF-α that are detrimental to pregnancy) and promotes a Th2 bias, which is considered protective for pregnancy maintenance. Reduced IL-10 levels have been associated with miscarriage and pre-eclampsia. IL-10 also inhibits antigen presentation and pro-inflammatory cytokine production.
📘 Q49 (Immunology) — A 35-year-old woman with myasthenia gravis is planning pregnancy. She is on pyridostigmine and mycophenolate mofetil. Which of the following statements about this scenario is most accurate? A) Mycophenolate mofetil is safe in pregnancy B) Neonatal myasthenia occurs in 10–20% of babies due to transplacental passage of maternal IgG anti-AChR antibodies C) Pregnancy universally improves myasthenia gravis D) Caesarean section is always required E) Breastfeeding is contraindicated
Answer: B
Maternal IgG anti-acetylcholine receptor (AChR) antibodies cross the placenta via FcRn and can cause transient neonatal myasthenia gravis in 10–20% of infants, characterized by hypotonia, poor feeding, and respiratory difficulty that resolves within 2–4 weeks. Mycophenolate mofetil is teratogenic (associated with first-trimester pregnancy loss and congenital malformations) and should be discontinued before pregnancy. Myasthenia gravis can worsen, improve, or remain stable in pregnancy.
📘 Q50 (Immunology) — Which of the following complement proteins acts as an opsonin and is the most abundant complement protein in serum? A) C1q B) C3 C) C4 D) C5 E) Factor B
Answer: B
C3 is the most abundant complement protein in serum (1–2 mg/mL) and is central to all three complement pathways. C3b, the activated fragment, acts as a powerful opsonin — it covalently binds to microbial surfaces and is recognized by complement receptors (CR1, CR3) on phagocytes, enhancing phagocytosis. C3b also forms part of the C5 convertase that initiates the membrane attack complex (MAC). C3 deficiency is associated with severe, recurrent pyogenic infections.
📘 Q51 (Clinical & Surgical Sciences) — A 35-year-old woman presents with intermenstrual bleeding and postcoital bleeding. On speculum examination, the cervix appears irregular and friable. Which of the following is the most appropriate initial investigation? A) Cervical smear (cytology) B) Colposcopy and cervical biopsy C) Endocervical curettage D) Cone biopsy E) MRI pelvis
Answer: B
Postcoital and intermenstrual bleeding with a visibly abnormal cervix requires colposcopy and directed cervical biopsy as the first-line investigation. Cervical cytology (smear) is a screening test, not diagnostic, and may be falsely negative with overt lesions. Cone biopsy is therapeutic and diagnostic but not the initial step. MRI is used for staging once diagnosis is confirmed. Colposcopy allows direct visualization of the transformation zone and targeted biopsy of abnormal areas.
📘 Q52 (Clinical & Surgical Sciences) — A 28-year-old woman with a BMI of 32 kg/m² is scheduled for an elective caesarean section under regional anaesthesia. According to surgical site infection (SSI) prevention guidelines, which of the following is the most important preoperative measure? A) Routine preoperative urinary catheterization B) Administer prophylactic antibiotics within 60 minutes before skin incision C) Shave pubic hair 24 hours before surgery D) Chlorhexidine shower the night before E) Insert a drain before wound closure
Answer: B
The single most important intervention to prevent SSI is the timely administration of prophylactic antibiotics (typically a first-generation cephalosporin) within 60 minutes before skin incision. This achieves adequate tissue concentrations at the time of bacterial contamination. Hair removal should be performed with clippers immediately before surgery (not shaving 24 hours prior, which increases SSI risk). Preoperative showering is recommended but less critical than antibiotic timing.
📘 Q53 (Clinical & Surgical Sciences) — During a diagnostic laparoscopy, the surgeon notes that the Veress needle has been inserted and the initial insufflation pressure is 25 mmHg. Which of the following is the most likely cause? A) The patient is obese B) The needle tip is in the preperitoneal space C) The gas cylinder is nearly empty D) Normal initial pressure E) The patient has adhesions
Answer: B
A high initial insufflation pressure (>20 mmHg) during Veress needle insertion suggests the needle tip is incorrectly positioned, most commonly in the preperitoneal space (between the fascia and peritoneum). A correctly positioned Veress needle should show initial pressures of 5–10 mmHg, free flow of gas, and a characteristic drop in pressure once insufflation begins. Preperitoneal insufflation can cause subcutaneous emphysema and increases the risk of failed peritoneal entry.
📘 Q54 (Clinical & Surgical Sciences) — A 32-year-old woman is undergoing a total laparoscopic hysterectomy. Which of the following electrosurgical principles is most important to prevent capacitive coupling injury? A) Use of monopolar diathermy in active electrode monitoring mode B) Use of all-metal trocar systems C) Avoiding activation of the electrode when not in contact with tissue D) Use of low voltage (cut mode) rather than coagulation mode E) Keeping the generator power output as low as possible
Answer: B
Capacitive coupling occurs when electrical current is transferred from the active electrode through intact insulation to adjacent conductive structures (e.g., bowel). Using all-metal trocar systems allows any coupled current to safely dissipate through the abdominal wall. Hybrid (plastic/metal) trocar systems can create a capacitor with no safe path for current dissipation, leading to burns. Active electrode monitoring (AEM) systems are also effective but all-metal trocars are the basic principle.
📘 Q55 (Clinical & Surgical Sciences) — A 40-year-old woman is scheduled for an abdominal hysterectomy for fibroids. She has a history of DVT 3 years ago. Which of the following is the most appropriate thromboprophylaxis? A) Early mobilization only B) Graduated compression stockings alone C) Low molecular weight heparin (LMWH) plus graduated compression stockings D) Oral anticoagulation with warfarin E) Intermittent pneumatic compression devices alone
Answer: C
This patient has a high risk for VTE (major pelvic surgery plus prior DVT). The RCOG guideline recommends combined thromboprophylaxis with LMWH and mechanical methods (graduated compression stockings or intermittent pneumatic compression) for high-risk patients undergoing major gynaecological surgery. LMWH should be continued for at least 7 days postoperatively (extended to 4–6 weeks for cancer surgery or high-risk patients). Warfarin is not used for perioperative prophylaxis due to slow onset and need for monitoring.
📘 Q56 (Clinical & Surgical Sciences) — A 34-year-old woman presents with acute lower abdominal pain and vomiting. On examination, she has tenderness and guarding in the right iliac fossa. Urine β-hCG is negative. Which of the following clinical signs would most strongly suggest appendicitis rather than gynaecological pathology? A) Cervical excitation (chandelier sign) B) Rovsing's sign C) Murphy's sign D) Blumberg's sign (rebound tenderness) E) Psoas sign
Answer: B
Rovsing's sign (palpation of the left lower quadrant causes pain in the right lower quadrant) is specific for appendicitis and suggests peritoneal irritation from an inflamed appendix. Cervical excitation suggests pelvic inflammatory disease or ruptured ovarian cyst. Murphy's sign (inspiratory arrest on RUQ palpation) is for cholecystitis. Psoas sign and rebound tenderness can occur in both appendicitis and gynaecological conditions, though they support peritonism.
📘 Q57 (Clinical & Surgical Sciences) — A 29-year-old woman undergoes an emergency caesarean section under general anaesthesia. Which of the following is the most important indication for using a non-depolarizing neuromuscular blocking agent (e.g., atracurium) rather than succinylcholine? A) Prolonged surgery anticipated B) History of malignant hyperthermia C) Asthma D) Obesity E) Fetal distress
Answer: B
Succinylcholine (suxamethonium) is a depolarizing neuromuscular blocker that is contraindicated in patients with or at risk of malignant hyperthermia (MH). MH is a life-threatening pharmacogenetic condition triggered by volatile anaesthetics and succinylcholine. Non-depolarizing agents like atracurium, rocuronium, or vecuronium are safe alternatives. Succinylcholine is preferred for rapid sequence induction (RSI) in most obstetric emergencies due to its fast onset and short duration, but is absolutely contraindicated in MH-susceptible patients.
📘 Q58 (Clinical & Surgical Sciences) — A 38-year-old woman is 1 hour post-abdominal hysterectomy. Her urine output has been 20 mL for the past hour. Blood pressure is 100/60 mmHg (baseline 120/80), pulse 110 bpm. Which of the following is the most appropriate immediate action? A) Administer a 500 mL bolus of crystalloid B) Prescribe furosemide 40 mg IV C) Request a renal ultrasound D) Increase the rate of maintenance IV fluids E) Check serum creatinine and urea
Answer: A
Oliguria (<0.5 mL/kg/hour) in the immediate postoperative period with tachycardia and relative hypotension suggests hypovolaemia. The appropriate first step is a fluid challenge (250–500 mL crystalloid bolus) to assess for haemodynamic response. Furosemide is contraindicated in hypovolaemia. Investigations are appropriate but should not delay initial resuscitation. Ongoing oliguria despite fluid resuscitation warrants investigation for acute kidney injury, and in gynaecological surgery, consideration of ureteric injury.
📘 Q59 (Clinical & Surgical Sciences) — Which of the following sutures is most appropriate for closing the uterine incision at caesarean section? A) Polyglactin 910 (Vicryl) B) Silk C) Nylon (Ethilon) D) Polydioxanone (PDS) E) Chromic catgut
Answer: A
Polyglactin 910 (Vicryl) is a synthetic, braided, absorbable suture that is the most commonly used material for uterine closure at caesarean section. It provides adequate tensile strength for 3–4 weeks and is fully absorbed by hydrolysis within 56–70 days. PDS is monofilament with prolonged absorption (180+ days) and may be used for continuous closure. Chromic catgut is natural, absorbed by proteolysis, and causes more tissue reaction. Silk and nylon are non-absorbable and inappropriate for uterine closure.
📘 Q60 (Clinical & Surgical Sciences) — A 45-year-old woman presents with heavy menstrual bleeding and is found to have a 10-week size fibroid uterus. She wishes to preserve fertility. Which of the following is the most appropriate surgical management? A) Total abdominal hysterectomy B) Subtotal hysterectomy C) Myomectomy D) Endometrial ablation E) Uterine artery embolization
Answer: C
Myomectomy is the surgical treatment of choice for symptomatic fibroids in women who wish to preserve fertility. It involves surgical removal of fibroids while preserving the uterus. Hysterectomy is definitive but ends fertility. Endometrial ablation is not appropriate for fibroids causing uterine enlargement >12 weeks or if future pregnancy is desired. Uterine artery embolization is fertility-preserving in some cases but has higher rates of ovarian failure and pregnancy complications compared to myomectomy.
📘 Q61 (Clinical & Surgical Sciences) — During a diagnostic hysteroscopy, the uterine cavity appears distended, but visualization is poor due to bubbles and debris. Which of the following distension media is most appropriate? A) Carbon dioxide gas B) Normal saline C) Glycine 1.5% D) Sorbitol 3% E) Mannitol 5%
Answer: B
Normal saline (0.9% NaCl) is the preferred distension medium for diagnostic and operative hysteroscopy when using bipolar electrosurgery. It provides excellent visualization, is inexpensive, and is isotonic (minimizing risk of hyponatraemia if absorbed). Glycine, sorbitol, and mannitol are non-electrolyte, hypotonic solutions used with monopolar electrosurgery; they carry a risk of dilutional hyponatraemia and TURP syndrome. CO₂ gas is used for diagnostic hysteroscopy but provides poorer visualization and can cause shoulder tip pain.
📘 Q62 (Clinical & Surgical Sciences) — A 26-year-old woman undergoes a laparoscopic ovarian cystectomy for a dermoid cyst. Which of the following is the most important intraoperative precaution to prevent a serious complication specific to this type of cyst? A) Careful haemostasis B) Minimizing spillage of cyst contents C) Using a morcellator D) Draining the cyst before removal E) Obtaining frozen section
Answer: B
Dermoid cysts (mature cystic teratomas) contain sebaceous material, hair, and teeth. Spillage of cyst contents can cause chemical peritonitis (granulomatous peritonitis), which is painful and difficult to manage. The cyst should be removed intact if possible, using an endobag for retrieval. If spillage occurs, copious irrigation is required. Frozen section is indicated if there is suspicion of malignancy but does not prevent chemical peritonitis.
📘 Q63 (Clinical & Surgical Sciences) — A 52-year-old woman is diagnosed with stage IB cervical cancer and is scheduled for a radical hysterectomy. Which of the following structures is most at risk of injury during dissection of the ureter in the parametrial tunnel? A) Internal iliac artery B) Obturator nerve C) Uterine artery D) Rectum E) Bladder
Answer: C
During radical hysterectomy (Wertheim's procedure), the ureter is dissected free in the "tunnel" (ureteric canal) through the parametrium. The uterine artery crosses superior to the ureter at this point ("water under the bridge" — ureter passes under the uterine artery). The uterine artery is ligated at its origin from the internal iliac or after crossing the ureter. Careful dissection is needed to avoid ureteric devascularization, which can lead to fistula formation.
📘 Q64 (Clinical & Surgical Sciences) — A 33-year-old woman presents with a pelvic abscess 5 days after an emergency caesarean section. Ultrasound shows a 6 cm complex collection in the pouch of Douglas. She is febrile (38.8°C) with rising inflammatory markers despite intravenous antibiotics. Which of the following is the most appropriate next step? A) Continue current antibiotics for another 48 hours B) CT-guided drainage of the abscess C) Laparotomy and drainage D) Hysterectomy E) MRI pelvis
Answer: B
Antibiotics alone are often insufficient for pelvic abscesses >3–4 cm due to poor penetration. CT-guided (or ultrasound-guided) drainage is the minimally invasive treatment of choice for accessible pelvic abscesses. It avoids the morbidity of laparotomy and has high success rates. Laparotomy is reserved for cases where drainage is not feasible or if there is suspected bowel injury. Hysterectomy is a last resort in a febrile, septic patient.
📘 Q65 (Clinical & Surgical Sciences) — A 24-year-old woman undergoes an examination under anaesthesia (EUA) and diagnostic laparoscopy for chronic pelvic pain. Which of the following findings at laparoscopy is most consistent with endometriosis? A) Dense adhesions between the appendix and omentum B) "Powder-burn" lesions (dark brown/black spots) on the uterosacral ligaments C) A unilocular ovarian cyst with clear fluid D) A hydrosalpinx E) Enlarged, polycystic ovaries
Answer: B
"Powder-burn" or "gunshot" lesions — dark brown, black, or bluish spots on the peritoneum, uterosacral ligaments, and ovarian surface — are classic laparoscopic findings of endometriosis. These represent ectopic endometrial deposits with haemorrhage and haemosiderin deposition. Other manifestations include red/flame lesions (early), peritoneal pockets, endometriomas (chocolate cysts), and adhesions. Histological confirmation is recommended. Hydrosalpinx suggests previous PID. PCO is an endocrine finding.
📘 Q66 (Clinical & Surgical Sciences) — A 30-year-old woman undergoes laparoscopic sterilisation using Filshie clips. Which of the following best describes the correct anatomical placement of the clip? A) Across the cornual portion of the fallopian tube B) Across the isthmic portion of the fallopian tube, 1–2 cm from the cornua C) Across the fimbrial end of the fallopian tube D) Across the broad ligament adjacent to the tube E) Across the ovarian ligament
Answer: B
Filshie clips are titanium-silicone lined clips applied to the isthmic portion of the fallopian tube, approximately 1–2 cm from the cornual (uterine) end. This location has a favourable ratio of tube wall thickness to lumen diameter, ensuring complete tubal occlusion with minimal risk of recanalization. Placement too close to the cornua risks incomplete occlusion or tubal transection. Clips should not be placed on the fimbriae or broad ligament as these sites have high failure rates.
📘 Q67 (Clinical & Surgical Sciences) — A 65-year-old woman with uterine prolapse (grade 3) is scheduled for a vaginal hysterectomy with pelvic floor repair. She has hypertension and type 2 diabetes. Which of the following positions is most appropriate for this surgery? A) Supine B) Lloyd-Davies C) Trendelenburg D) Lithotomy E) Lateral
Answer: D
Lithotomy position (with adjustable supports for the legs) is the standard position for vaginal surgery, including vaginal hysterectomy and pelvic floor repair. It provides optimal access to the perineum and vagina. Caution is needed with prolonged lithotomy due to risk of compartment syndrome and nerve injury (common peroneal, sciatic). Lloyd-Davies position (modified lithotomy with hip flexion less extreme) is used for abdominoperineal or laparoscopic procedures.
📘 Q68 (Clinical & Surgical Sciences) — A 37-year-old woman presents with a suspected ectopic pregnancy at 7 weeks' gestation. Her serum β-hCG is 2500 IU/L. Transvaginal ultrasound shows no intrauterine pregnancy and no adnexal mass. Which of the following is the most appropriate next step? A) Repeat β-hCG in 48 hours B) Diagnostic laparoscopy C) Methotrexate therapy D) Dilation and curettage E) MRI pelvis
Answer: B
With β-hCG ≥1500 IU/L (the discriminatory zone) and no evidence of an intrauterine pregnancy on transvaginal ultrasound, the risk of ectopic pregnancy is very high. A diagnostic laparoscopy is indicated to definitively locate the pregnancy. Repeat β-hCG is appropriate when β-hCG is below the discriminatory zone and the patient is stable. Methotrexate should not be given without confirming the diagnosis. D&C can be done to distinguish failed IUP from ectopic but is less definitive.
📘 Q69 (Clinical & Surgical Sciences) — A 42-year-old woman is undergoing a total laparoscopic hysterectomy. The surgeon uses a 10 mm laparoscope and a 5 mm accessory port. Which of the following is the most appropriate location for the primary (umbilical) port entry? A) Directly through the umbilicus B) 5 cm above the umbilicus C) At the McBurney point D) In the left upper quadrant (Palmer's point) E) Suprapubic midline
Answer: A
The umbilicus is the thinnest point of the abdominal wall with fused fascial layers, making it the preferred site for primary port entry (Veress needle or direct trocar insertion). A 10 mm umbilical port provides optimal access for the laparoscope. Palmer's point (left upper quadrant, 3 cm below the costal margin in the midclavicular line) is the alternative entry site when there is concern about umbilical adhesions (e.g., previous midline laparotomy).
📘 Q70 (Clinical & Surgical Sciences) — A 28-year-old woman is 4 hours post-laparoscopic cholecystectomy (performed by general surgery). She reports severe right shoulder tip pain. Which of the following is the most likely cause? A) Bile leak B) Subdiaphragmatic abscess C) Phrenic nerve irritation from residual CO₂ D) Port site infection E) Gallbladder bed haematoma
Answer: C
Shoulder tip pain after laparoscopy is common (referred pain via the phrenic nerve, C3–5) caused by residual CO₂ gas irritating the diaphragmatic peritoneum. It typically resolves within 24–48 hours as the gas is absorbed. Conservative management (analgesia, ambulation) is sufficient. Persistent or worsening pain with fever or shoulder pain after 48 hours should raise suspicion for other pathology. Bile leak or abscess would present with peritonism and sepsis, not isolated shoulder pain.
📘 Q71 (Clinical & Surgical Sciences) — A 34-year-old woman requires an emergency caesarean section for plac central abruption with fetal bradycardia. She has a platelet count of 70 × 10⁹/L. Which of the following anaesthetic techniques is most appropriate? A) Spinal anaesthesia B) Epidural anaesthesia C) Combined spinal-epidural D) General anaesthesia E) Local infiltration
Answer: D
With a platelet count of 70 × 10⁹/L, neuraxial (spinal/epidural) anaesthesia is relatively contraindicated due to increased risk of epidural haematoma. Most guidelines recommend a platelet count >70–80 × 10⁹/L for epidural and >50–70 × 10⁹/L for spinal anaesthesia. Given the urgency (fetal bradycardia) and the relative contraindication to regional anaesthesia, general anaesthesia is the safest choice. The low platelets may also reflect consumptive coagulopathy from abruption.
📘 Q72 (Clinical & Surgical Sciences) — A 33-year-old woman is undergoing an examination under anaesthesia for suspected uterine perforation following a surgical termination of pregnancy. Which of the following instruments is most suitable for confirming the diagnosis? A) Hysteroscope B) Sound C) Curette D) Tenaculum E) Dilator
Answer: A
Hysteroscopy is the most reliable method to directly visualize the uterine cavity and confirm or exclude uterine perforation. It allows assessment of the size and location of the perforation and helps guide management (expectant vs. laparoscopic repair). A uterine sound or dilator can be used to gently probe but may extend the perforation and is less accurate. Laparoscopy is indicated if there is concern about bowel or bladder injury or if hysteroscopy is inconclusive.
📘 Q73 (Clinical & Surgical Sciences) — A 48-year-old woman undergoes a vaginal hysterectomy for uterovaginal prolapse. Which of the following is the most common immediate postoperative complication specific to vaginal hysterectomy? A) Wound infection B) Haemorrhage from the vaginal cuff C) Deep vein thrombosis D) Urinary retention E) Ileus
Answer: D
Urinary retention is the most common immediate complication following vaginal hysterectomy, occurring in 5–25% of cases. This is due to perioperative manipulation, oedema of the bladder base, and pain inhibiting the micturition reflex. A transurethral or suprapubic catheter is typically left in situ for 24–48 hours. Vaginal cuff bleeding/ haematoma is an important but less common complication. DVT prophylaxis is routine.
📘 Q74 (Clinical & Surgical Sciences) — A 25-year-old woman with a history of three previous caesarean sections is now at 38 weeks with a singleton breech presentation. She is counselled about vaginal birth after caesarean (VBAC) vs. elective repeat caesarean section (ERCS). Which of the following is the most significant risk of VBAC in this scenario? A) Placenta praevia B) Uterine rupture C) Shoulder dystocia D) Postpartum haemorrhage E) Cord prolapse
Answer: B
The risk of uterine rupture during VBAC increases with the number of previous caesarean sections. With three or more prior caesarean sections, VBAC is generally not recommended (risk of uterine rupture ~1–4% vs. 0.5% for one prior section). Breech presentation is also a relative contraindication to VBAC. Uterine rupture is a catastrophic complication with significant maternal and fetal morbidity/ mortality options. Placenta praevia is a risk factor for future pregnancies but not directly for VBAC.
📘 Q75 (Clinical & Surgical Sciences) — A 36-year-old woman is diagnosed with a 7 cm ovarian cyst that is unilocular, anechoic, and thin-walled on ultrasound. CA-125 is 12 U/mL. She is asymptomatic. Which of the following is the most appropriate management? A) Laparoscopic oophorectomy B) Annual ultrasound follow-up C) CT scan of abdomen and pelvis D) Laparoscopic cystectomy E) Ovarian cyst aspiration
Answer: B
Simple anechoic, unilocular cysts <10 cm in premenopausal women with normal CA-125 have a very low risk of malignancy (<1%). The RCOG recommends conservative management with annual follow-up ultrasound. Surgery (cystectomy or oophorectomy) is reserved for complex features (septations, solid areas, papillary projections, ascites) or symptomatic cysts. Cyst aspiration is not recommended due to high recurrence rates and risk of seeding malignant cells.
📘 Q76 (Clinical & Surgical Sciences) — A 34-year-old woman is undergoing a myomectomy for a single 8 cm intramural fibroid. Which of the following is the most important step to minimize intraoperative blood loss? A) Preoperative GnRH agonist therapy for 3 months B) Using a harmonic scalpel C) Injection of vasopressin into the myometrium around the fibroid D) Tourniquet around the uterine vessels E) Preoperative embolization
Answer: C
Injection of dilute vasopressin (or its synthetic analogue) into the myometrium and pseudocapsule surrounding the fibroid causes potent vasoconstriction and significantly reduces intraoperative blood loss during myomectomy. This is the most widely used and evidence-based intervention. GnRH agonists reduce fibroid size and vascularity but require 2–3 months of therapy and are not an intraoperative measure. Tourniquets and embolization are alternative methods but vasopressin injection is the most practical first-line intraoperative technique.
📘 Q77 (Fetal Physiology) — At 32 weeks' gestation, which of the following structures allows most of the oxygenated blood from the placenta to bypass the fetal liver? A) Foramen ovale B) Ductus arteriosus C) Ductus venosus D) Umbilical artery E) Pulmonary vein
Answer: C
The ductus venosus is a fetal vascular shunt that connects the umbilical vein to the inferior vena cava (IVC), allowing ~40–60% of oxygenated placental blood to bypass the hepatic sinusoids. The remainder perfuses the left lobe of the liver (which receives more highly oxygenated blood than the right lobe). The foramen ovale shunts blood from the right to the left atrium. The ductus arteriosus shunts blood from the pulmonary artery to the descending aorta. The umbilical arteries carry deoxygenated blood to the placenta.
📘 Q78 (Fetal Physiology) — Which of the following best describes the normal fetal haemoglobin (HbF) composition at term? A) 50% HbF, 50% HbA B) 60–80% HbF, 20–40% HbA C) 90–95% HbF, 5–10% HbA D) 100% HbF, 0% HbA E) 70% HbF, 30% HbA
Answer: C
At term, fetal haemoglobin (HbF, α₂γ₂) constitutes approximately 90–95% of total haemoglobin, with the remainder being HbA (α₂β₂). HbF has a higher affinity for oxygen than HbA due to its weaker binding to 2,3-DPG, which facilitates oxygen transfer across the placenta from maternal to fetal circulation. HbF production begins to decline after 30–34 weeks as HbA production increases. By 6 months of age, HbF is largely replaced by HbA.
📘 Q79 (Fetal Physiology) — A 34-year-old woman at 38 weeks' gestation is in established labour. The fetal scalp pH is measured and found to be 7.20. Which of the following is the most appropriate interpretation of this result? A) Normal — no action needed B) Borderline acidosis — repeat in 30 minutes C) Severe acidosis — immediate delivery indicated D) Result is unreliable due to maternal alkalosis E) Indicates metabolic acidosis only
Answer: B
Fetal scalp blood sampling pH interpretation: normal >7.25, borderline 7.20–7.25, abnormal <7.20. A pH of 7.20 is borderline and should be repeated in 30 minutes or sooner if the CTG deteriorates. If the repeat pH is <7.20, immediate delivery is indicated. The base deficit should also be assessed to distinguish respiratory from metabolic acidosis. A pH <7.00 with metabolic acidosis is associated with increased risk of neonatal encephalopathy.
📘 Q80 (Fetal Physiology) — Which of the following is the most accurate description of the fetal circulation pattern (preload and afterload) in utero? A) Both ventricles have high afterload B) The right ventricle pumps against high afterload (pulmonary circulation) while the left ventricle has low afterload C) The right ventricle pumps against high afterload (systemic circulation via ductus arteriosus) while the left ventricle has low afterload D) Both ventricles have low afterload E) The right ventricle has low afterload while the left ventricle has high afterload
Answer: C
In utero, the right ventricle ejects blood into the pulmonary artery, but due to high pulmonary vascular resistance (PVR), only ~10% goes to the lungs. The majority passes through the ductus arteriosus into the descending aorta, meaning the right ventricle pumps against systemic vascular resistance (high afterload). The left ventricle receives blood from the foramen ovale and pulmonary veins and ejects into the ascending aorta (supplying the brain and heart), facing relatively lower afterload. This is the opposite of postnatal circulation where the left ventricle handles high afterload.
📘 Q81 (Fetal Physiology) — A neonate born at 35 weeks' gestation develops respiratory distress soon after birth. Which of the following physiological factors is most likely contributing to this condition? A) Excessive surfactant production B) Deficiency of surfactant due to immaturity of type II pneumocytes C) Persistent ductus arteriosus D) Meconium aspiration E) Congenital diaphragmatic hernia
Answer: B
Neonatal respiratory distress syndrome (RDS) in preterm infants is primarily due to surfactant deficiency. Surfactant (a mixture of phospholipids, primarily dipalmitoylphosphatidylcholine (DPPC), and proteins) is produced by type II pneumocytes starting at around 24 weeks, but adequate production is not achieved until ~34–36 weeks. Surfactant reduces alveolar surface tension, preventing collapse at end-expiration. Antenatal corticosteroids (betamethasone) accelerate fetal lung maturity and surfactant production. At 35 weeks, there is relative immaturity.
📘 Q82 (Fetal Physiology) — At birth, which of the following events triggers the closure of the ductus arteriosus? A) Decreased PO₂ and increased prostaglandin levels B) Increased PO₂ and decreased prostaglandin levels C) Increased pulmonary vascular resistance D) Decreased systemic vascular resistance E) Closure of the foramen ovale
Answer: B
At birth, the first breaths cause lung expansion and a dramatic increase in alveolar and arterial PO₂. This increase in oxygen tension, combined with a decrease in circulating prostaglandins (particularly PGE₂, which maintains ductal patency in utero), triggers ductus arteriosus constriction. Functional closure occurs within 24–48 hours; anatomical closure (ligamentum arteriosum) takes 2–3 weeks. In preterm infants, the ductus may remain patent (PDA) due to immature response to oxygen and persistent prostaglandins.
📘 Q83 (Fetal Physiology) — A 40-week-gestation neonate has Apgar scores of 4 at 1 minute and 7 at 5 minutes. Which of the following components of the Apgar score is assessed by observing the baby's response to a catheter in the nostril? A) Heart rate B) Respiratory effort C) Muscle tone D) Reflex irritability E) Colour
Answer: D
Reflex irritability is one of the five Apgar components (the others being Heart rate, Respiratory effort, Muscle tone, and Colour). It is assessed by stimulating the baby (e.g., gentle suction of the oropharynx or rubbing the back) and observing the response: grimace or cough/sneeze = score 1; vigorous cry or active withdrawal = score 2; no response = score 0. The 1-minute Apgar of 4 indicates moderately depressed requiring resuscitation.
📘 Q84 (Fetal Physiology) — Which of the following is the most accurate statement regarding fetal growth restriction (FGR)? A) FGR is always associated with a low ponderal index B) Asymmetric FGR is typically caused by placental insufficiency C) Symmetric FGR is most commonly due to placental insufficiency D) FGR is synonymous with small-for-gestational-age (SGA) E) Doppler velocimetry of the umbilical artery is normal in FGR
Answer: B
Asymmetric (late-onset) FGR is characterized by relative sparing of head growth compared to abdominal circumference and is typically caused by placental insufficiency. The brain-sparing effect redirects cardiac output to the cerebral circulation. Umbilical artery Doppler typically shows raised PI and/or absent/reversed end-diastolic flow. Symmetric FGR is more commonly due to early insults (congenital infections, chromosomal anomalies, teratogens). FGR refers to a fetus that has not reached its growth potential; not all SGA fetuses are growth-restricted (constitutionally small is normal).
📘 Q85 (Fetal Physiology) — Which of the following hormones is primarily responsible for maintaining pregnancy after 8–10 weeks' gestation? A) Human chorionic gonadotropin (hCG) B) Progesterone C) Oestradiol D) Human placental lactogen (hPL) E) Relaxin
Answer: B
Progesterone is the critical hormone for pregnancy maintenance throughout gestation. It is produced by the corpus luteum under LH stimulation for the first 8–10 weeks (the "luteal-placental shift"), after which the placenta becomes the primary source. Progesterone suppresses uterine contractility (maintains quiescence), modulates the maternal immune response to tolerate the fetal semi-allograft, and supports the endometrial decidua. hCG is crucial in early pregnancy for luteal support but declines after the first trimester.
📘 Q86 (Fetal Physiology) — A term neonate is noted to have acrocyanosis (blue hands and feet) at 5 minutes of age but is active, crying vigorously, with a heart rate of 140 bpm. Which of the following is the most appropriate interpretation? A) The baby has severe respiratory distress B) The baby has a congenital heart defect C) This is a normal finding in the immediate neonatal period D) The baby requires immediate oxygen therapy E) The baby has sepsis
Answer: C
Acrocyanosis (cyanosis of the hands and feet only) is a normal finding in the first 24–48 hours of life due to peripheral vasomotor instability and relatively slow peripheral circulation. It does not indicate hypoxaemia. Central cyanosis (involving the lips, tongue, and trunk) is abnormal and requires investigation. The baby described has a normal heart rate, vigorous activity, and good respiratory effort — reassuring features. The Apgar colour score would be 1 (body pink, extremities blue).
📘 Q87 (Fetal Physiology) — Which of the following best describes the physiological function of brown adipose tissue (BAT) in the neonate? A) It stores glycogen for gluconeogenesis B) It generates heat through non-shivering thermogenesis mediated by uncoupling protein 1 (UCP1) C) It produces surfactant D) It stores iron for erythropoiesis E) It secretes insulin-like growth factor
Answer: B
Brown adipose tissue (BAT) is specialized for non-shivering thermogenesis, which is the primary mechanism of heat production in neonates. BAT mitochondria contain uncoupling protein 1 (UCP1/thermogenin), which uncouples oxidative phosphorylation from ATP production, generating heat instead. BAT is located in the interscapular region, axillae, and around the kidneys. It is well-developed in term neonates but decreased in preterm and SGA infants, contributing to their higher risk of hypothermia. Shivering thermogenesis develops later in infancy.
📘 Q88 (Fetal Physiology) — A 28-year-old woman at 39 weeks' gestation has a pathological CTG with recurrent late decelerations. Which of the following fetal physiological responses is most likely occurring? A) Increased fetal heart rate variability B) Fetal hypertension and bradycardia due to chemoreceptor activation C) Increased fetal movements D) Peripheral vasoconstriction and redistribution of cardiac output to vital organs E) Increased pulmonary blood flow
Answer: D
Late decelerations indicate uteroplacental insufficiency and fetal hypoxaemia. In response to hypoxia, the fetus activates a "diving reflex" (centralization of circulation): chemoreceptor and baroreceptor responses cause peripheral vasoconstriction, hypertension, and redistribution of cardiac output to vital organs (brain, heart, adrenals) at the expense of non-vital organs (kidneys, gut, lungs, periphery). This manifests clinically as late decelerations on CTG. If hypoxaemia persists, metabolic acidosis develops as anaerobic metabolism produces lactate.
📘 Q89 (Fetal Physiology) — A 32-year-old primigravida at 41 weeks' gestation undergoes a caesarean section for failure to progress. The amniotic fluid is meconium-stained. Which of the following explains the physiological basis for meconium passage in post-term pregnancy? A) Increased fetal insulin levels B) Fetal hypoxia stimulating vagal activity and GI peristalsis C) Decreased fetal cortisol levels D) Maturation of the fetal liver E) Increased prostaglandin E2 in fetal circulation
Answer: B
Meconium passage in post-term or stressed fetuses is thought to result from vagal stimulation due to hypoxia/acidosis, which increases gut peristalsis and relaxes the anal sphincter. Post-term pregnancies (>41+6 weeks) have increased risk of placental insufficiency, leading to chronic fetal hypoxia. Meconium-stained liquor in the presence of abnormal CTG is associated with increased risk of meconium aspiration syndrome (MAS). However, meconium at term in an otherwise low-risk pregnancy may be physiological.
📘 Q90 (Fetal Physiology) — Which of the following is the primary role of fetal cortisol in relation to the transition from intrauterine to extrauterine life? A) Stimulating fetal lung surfactant production B) Initiating closure of the ductus arteriosus C) Promoting the conversion of HbF to HbA D) Suppressing fetal adrenal function E) Promoting glycogen storage in the fetal liver
Answer: A
The prepartum surge in fetal cortisol is critical for fetal lung maturation. Cortisol upregulates the production of surfactant phospholipids and proteins by type II pneumocytes, enhances lung compliance, and induces structural maturation of the alveoli. This is the rationale for administering antenatal corticosteroids (betamethasone) to women at risk of preterm delivery. Cortisol also contributes to maturation of other fetal organ systems (liver, gut, kidney) and may play a role in the initiation of labour.
📘 Q91 (Fetal Physiology) — A neonate born at 38 weeks' gestation has a bilirubin level of 280 μmol/L at 72 hours of life. Which of the following physiological factors contributes most significantly to physiological jaundice in term neonates? A) Increased bilirubin clearance due to mature hepatic function B) Increased RBC lifespan and low RBC mass C) Increased bilirubin production (haemolysis of fetal RBCs) and immature hepatic conjugation (low UDP-glucuronosyltransferase activity) D) Decreased enterohepatic circulation E) Increased albumin binding capacity
Answer: C
Physiological jaundice in neonates results from two main factors: (1) increased bilirubin production due to breakdown of fetal RBCs (short lifespan of ~90 days) and higher RBC mass, and (2) immature hepatic function, specifically low activity of UDP-glucuronosyltransferase (UGT1A1), which conjugates bilirubin for excretion. Additionally, increased enterohepatic circulation (due to β-glucuronidase in neonatal gut) contributes. Term infants have physiological jaundice peaking at 3–5 days. Higher or earlier levels require investigation for pathological causes.
📘 Q92 (Fetal Physiology) — Which of the following best describes the fetal cardiovascular adaptation to chronic hypoxaemia in growth-restricted fetuses? A) Decreased cerebral blood flow B) Increased flow in the umbilical artery C) Redistribution of cardiac output with increased middle cerebral artery (MCA) blood flow D) Decreased ductus venosus flow E) Increased pulmonary artery blood flow
Answer: C
In chronic fetal hypoxaemia (as in placental insufficiency), the fetus responds by redistributing cardiac output to maintain oxygen delivery to vital organs (brain, heart, adrenals) — the "brain-sparing effect." This is detected by Doppler ultrasound as increased diastolic flow in the MCA (decreased MCA PI). Umbilical artery Doppler shows increased resistance (raised PI) and may progress to absent or reversed end-diastolic flow (AREDF), indicating severe placental insufficiency. Ductus venosus Doppler changes reflect right heart strain.
📘 Q93 (Fetal Physiology) — At the moment of birth, which of the following physiological changes occurs FIRST in the neonate? A) Closure of the foramen ovale B) Closure of the ductus arteriosus C) Lung expansion with the first breath D) Increase in pulmonary vascular resistance E) Decrease in systemic vascular resistance
Answer: C
The first breath is the initial and critical event that triggers all other cardiovascular changes at birth. The first breath is stimulated by hypoxia, hypercapnia, acidosis, tactile stimuli, and thermal changes. Lung expansion leads to a dramatic fall in pulmonary vascular resistance (PVR) (not an increase), increased pulmonary blood flow, and increased left atrial pressure. This causes functional closure of the foramen ovale. The increase in PaO₂ triggers ductus arteriosus constriction. Systemic vascular resistance increases (loss of low-resistance placenta), not decreases.
📘 Q94 (Fetal Physiology) — A 26-year-old woman at 34 weeks' gestation is diagnosed with pre-eclampsia. Which of the following placental physiological changes is most characteristic of this condition? A) Normal trophoblast invasion B) Incomplete remodelling of spiral arteries leading to placental ischaemia C) Excessive angiogenesis in the placental villi D) Increased placental blood flow E) Decreased trophoblast apoptosis
Answer: B
Pre-eclampsia is characterized by failed/ incomplete physiological transformation of the maternal spiral arteries by invading extravillous trophoblast. Normally, trophoblast invasion converts narrow, high-resistance spiral arteries into wide, low-resistance vessels capable of supplying adequate blood flow to the placenta. In pre-eclampsia, this remodelling is incomplete (especially the second wave at 16–18 weeks), resulting in placental hypoxia/ ischaemia, oxidative stress, and release of anti-angiogenic factors (sFlt-1, sEng) into the maternal circulation, causing systemic endothelial dysfunction.
📘 Q95 (Fetal Physiology) — Which of the following is the most accurate statement regarding placental transfer of IgG antibodies? A) IgG transfer occurs mainly in the first trimester B) IgG transfer is mediated by passive diffusion C) IgG transfer is an active process mediated by neonatal Fc receptor (FcRn) on syncytiotrophoblast, increasing exponentially after 20 weeks D) IgG transfer is highest for IgG2 subclass E) Maternal infection impairs IgG transfer
Answer: C
Maternal IgG is actively transported across the placenta via neonatal Fc receptor (FcRn) expressed on syncytiotrophoblast cells. This transfer begins around 13 weeks' gestation but increases exponentially in the third trimester, reaching term cord blood IgG levels that equal or exceed maternal levels (by ~10% at term). IgG1 and IgG3 are transferred most efficiently, IgG4 moderately, and IgG2 least efficiently. This explains why preterm infants (born before 32–34 weeks) have reduced passive immunity.
📘 Q96 (Fetal Physiology) — A 38-week-gestation neonate develops tachypnoea soon after birth. CXR shows fluid in the lung fissures and prominent pulmonary vascular markings. Which of the following physiological mechanisms is most important for clearing fetal lung fluid at birth? A) Coughing B) Epithelial sodium channel (ENaC)-mediated sodium and water reabsorption C) Suctioning of the oropharynx D) Gravity drainage E) Lymphatic absorption
Answer: B
At birth, the switch from placental gas exchange to pulmonary gas exchange requires rapid clearance of fetal lung fluid (which fills the lungs in utero, ~30 mL/kg). The primary mechanism is active transepithelial sodium reabsorption via epithelial sodium channels (ENaC) on type II pneumocytes, driven by the surge in catecholamines (especially adrenaline) and cortisol at birth. Water follows osmotically and is cleared into the pulmonary interstitium and circulation (a process accelerated by vaginal delivery vs. caesarean). Delayed clearance causes transient tachypnoea of the newborn (TTN).
📘 Q97 (Fetal Physiology) — Which of the following is the primary energy substrate for the fetus during the first trimester? A) Glucose B) Lactate C) Ketone bodies D) Amino acids E) Free fatty acids
Answer: A
Glucose is the primary energy substrate for the fetus throughout gestation. It is transported across the placenta via facilitated diffusion through GLUT1 and GLUT3 transporters. Fetal glucose levels are approximately 70–80% of maternal levels. In the first trimester, the embryo relies primarily on anaerobic glycolysis. Amino acids are actively transported and used for protein synthesis and as an energy source. Free fatty acids cross the placenta less readily. Lactate produced by the placenta can be used by the fetus.
📘 Q98 (Fetal Physiology) — A 35-year-old woman at 40 weeks' gestation is in the second stage of labour. The CTG shows a prolonged deceleration lasting 8 minutes following a contraction. Which of the following is the most likely cause? A) Head compression (early deceleration) B) Umbilical cord compression (variable deceleration) C) Uteroplacental insufficiency (late deceleration) D) Maternal Valsalva manoeuvre causing reduced venous return E) Fetal seizure activity
Answer: B
A prolonged deceleration (>3 minutes) that follows a contraction pattern is most concerning for cord compression (prolonged variable deceleration). Prolonged decelerations may be caused by cord prolapse, cord entanglement, or sustained uterine hypertonus. An 8-minute deceleration indicates significant fetal hypoxia and requires immediate intervention — intrauterine resuscitation (maternal repositioning, oxygen, IV fluids, tocolysis) and/or expedited delivery. Early decelerations are benign head compression responses. Late decelerations indicate placental insufficiency.
📘 Q99 (Fetal Physiology) — Which of the following best describes the role of prostaglandins in the fetal circulation before birth? A) They maintain constriction of the ductus arteriosus B) They maintain patency of the ductus arteriosus C) They promote closure of the foramen ovale D) They constrict the umbilical arteries E) They dilate the pulmonary vasculature
Answer: B
Prostaglandins, particularly PGE₂, play a critical role in maintaining patency of the ductus arteriosus in utero. The fetal ductus arteriosus is maintained in a dilated state by low oxygen tension and circulating PGE₂ and prostacyclin (PGI₂). After birth, the increase in oxygen and decrease in PGE₂ levels (due to placental removal and increased pulmonary clearance) cause ductal constriction. This is why PGE₁ (alprostadil) is used pharmacologically to maintain ductal patency in neonates with duct-dependent congenital heart disease.
📘 Q100 (Fetal Physiology) — A term neonate has a venous cord blood gas showing pH 7.25, pCO₂ 55 mmHg, bicarbonate 23 mmol/L, base deficit 5 mmol/L. Which of the following is the most accurate interpretation? A) Normal cord blood gas B) Metabolic acidosis C) Respiratory acidosis D) Mixed acidosis E) Respiratory alkalosis
Answer: C
Venous cord blood gas reference: pH >7.25 is normal, pH 7.20–7.25 is borderline, pH <7.20 is abnormal. The pH of 7.25 is at the lower limit of normal. The pCO₂ is elevated (55 mmHg; normal ~35–45 mmHg) while the bicarbonate is normal (23 mmol/L; normal ~22–26 mmol/L) and base deficit is mild (−5 mmol/L; significant if >−12). This pattern is consistent with mild respiratory acidosis — a normal finding after labour due to transient CO₂ retention from uterine contractions, which resolves with establishment of neonatal respiration. Metabolic acidosis would show low bicarbonate and high base deficit.
End of Mock Exam 13 — 100 Questions