Mrcog High Yield Mnemonics

MRCOG Part 1 — High-Yield Mnemonics & Rapid Recall

Quick-fire mnemonics, acronyms, and memory aids organised by topic. Use these in your final week for rapid revision.

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1. ANATOMY

Bony Pelvis

• Pelvic shapes: "GAP Anterior" — Gynaecoid, Android, Platypelloid, Anthropoid
• Gynaecoid pelvis: "11-13-11" — AP 11cm, Transverse 13cm, Diagonal conjugate 11cm
• Pelvic inlet diameters (from smallest to largest): "OC T A" — Obstetric conjugate (11cm), Transverse (13cm), Anatomical conjugate (11cm)
• Levator ani muscles: "PICP" — Pubococcygeus, Iliococcygeus, (Ischiococcygeus), Puborectalis
• Perineal body muscles: "BACT" — Bulbospongiosus, (deep & superficial) transverse perineal muscles, Anal sphincter external muscle

Blood Supply

• Internal iliac artery — anterior division branches: "MAD I LOVE U" — (M)iddle rectal, (A)rtery to vas deferens, (D)eep circumflex iliac, (I)nferior vesical, (L)ateral circumflex femoral, (O)bturator, (V)aginal, (E) Internal pudendal, (U)mbilical (+ uterine). OR: "I Love Vegetables & Other Unique Meals" — Iliolumbar, Lateral sacral, Vesical (inferior), Vaginal, Obturator, Uterine, Middle rectal + Internal pudendal
• Ovarian artery origin: Level of L2 (Renal artery at L1-L2, Ovarian just below)
• Ovarian vein drainage: Right → IVC, Left → Left renal vein ("Right IVC, Left Renal")
• Uterine artery crosses above the ureter: "Water under the bridge" — Ureter passes UNDER uterine artery (at level of internal os)

Nerve Supply

• Pudendal nerve roots: "S2-3-4 keeps the floor off the door" — S2, S3, S4
• Pudendal nerve branches: "MINN" — (M)uscular, (I)nferior rectal, (N)erve to perineum, (N)erve to dorsal clitoris/penis
• Obturator nerve roots: "L2,3,4 keeps the thigh shut tight" (L2-L4)
• Pelvic splanchnic nerves (parasympathetic): "S2-3-4 keeps the bladder off the floor" — S2, S3, S4 — erector muscles, bladder, rectum
• Hypogastric plexus (sympathetic): "L1-L2 — fight or flight, hold the flow tight"

Lymphatics

• Cervical lymph drainage: "Iliac, Obturator, Sacral — remember 'IOS' for cervix"
• Vulval lymphatics: "Superficial inguinal first, deep inguinal second, pelvic third"
• Breast lymph drainage: 75% → Axillary, 20% → Internal mammary, 5% → Posterior intercostal ("AIM" — Axillary, Internal mammary, posterior intercostal)

Abdominal Wall

• Rectus sheath above arcuate line: "A-E-I" — Anterior (External oblique aponeurosis + Internal oblique), Posterior (Internal oblique + Transversus abdominis)
• Rectus sheath below arcuate line: "All three in front, nothing behind" — External oblique + Internal oblique + Transversus all pass anteriorly
• Hesselbach's triangle borders: "Lateral = Inferior epigastric, Medial = Rectus sheath, Base = Inguinal ligament" — "LIMB" = Lateral, Inferior epigastric, Medial, Base
• Inguinal canal contents (male): "It's A Dirty Dungeon" — (I)lioinguinal nerve, (A)rtery to vas, (D)uctus deferens, (D)artos muscle (cremasteric vessels, genital branch genitofemoral nerve)

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2. EMBRYOLOGY

Müllerian Development

• Paramesonephric (Müllerian) ducts → female: "UFT" — Upper → Fallopian tubes, Fusion → Uterus/cervix, Tract → upper vagina
• Wolffian (Mesonephric) ducts: "E-V-D" — (E)pididymis, (V)as deferens, (D)uctus deferens + seminal vesicles
• Urogenital sinus → lower structures: "BLUV" — Bladder, Lower vagina, Urethra, Vestibular (Bartholin's glands)
• Müllerian anomalies: "Did Uncle Steve Have A Uterus?" — Types 1: Dysgenesis, 2: Unicornuate, 3: Didelphys, 4: Bicornuate, 5: Septate (complete/incomplete), 6: Arcuate, 7: DES related

Foetal Structures

• Foetal shunts in order of closure: "Ductus arteriosus is Last" — DV closes → Foramen ovale → Ductus arteriosus (last to close anatomically)
• Foetal haemoglobin: HbF = α2γ2 (2 alpha, 2 gamma chains)
• Three shunts: "DDF" — Ductus venosus (bypasses liver), Ductus arteriosus (bypasses lungs), Foramen ovale (bypasses lungs)
• Umbilical cord: 2 arteries, 1 vein — "AVA" (Artery-Vein-Artery — tough to remember: "A-V-A = 2 A's = 2 arteries")

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3. GENETICS

Inheritance Patterns

• AR: "1-2-3" — 1 in 4 risk, 2 sexes equally, 3 = skips generations (carrier parents)
• AD: "1-2-3" — 1 affected parent → 50% risk, 2 generations (no skip), 3 = both sexes
• X-linked recessive: "Color blind on the X" — males affected (XY), females carriers (XX)
• Mitochondrial: "Mother to ALL children" — only mother passes to sons AND daughters
• Imprinting: "PG M" — Prader-Willi = Paternal deletion (15q), Angelman = Maternal deletion (15q)
• Triple test: "AFP low = Down's, AFP high = NTD" — "D for Down = D for decreased AFP"; "N for NTD = N for increased AFP"

Common Chromosomal Abnormalities

• Trisomies and their proteins: "21-Down, 18-Edwards, 13-Patau"
• Klinefelter (47,XXY): "Xtra X = Xtra tall, Xtra testes tiny"
• Turner (45,XO): "Only X = Only short, Only one ovary"
• Cri-du-Chat: "5p — Crying Cat on Chromosome 5 short arm"

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4. PHYSIOLOGY

Menstrual Cycle

• Follicular phase: Days 1-14 — "F for 'Follicle grows', F for 'Estrogen rises'"
• Luteal phase: Days 14-28 — "L for 'Luteinising', L for 'Progesterone'"
• Cycle length: 28 days ± 7 = normal range 21-35 days
• Ovulation: Day 14 in 28-day cycle = LH surge (surge lasts 24-48h, occurs 36h before ovulation)
• Endometrial phases: "PLM" — Proliferative (estrogen), Luteal (progesterone), Menstrual (fall)

Maternal Adaptations to Pregnancy

• Cardiovascular changes: "CO Rises 30-40% → Increased HR + SV"
• Blood volume: "Up 40-50%" — plasma increases more than RBC → physiological anaemia
• Physiological anaemia: "Hb drops 1-2 g/dL" due to disproportionate plasma increase
• Respiratory: "Tidal volume ↑ 30-40%, RR unchanged" → "T for Tidal (up), R for Rate (same)"
• Renal: "GFR up 50%" → "Pregnant kidneys filter faster — 50% better"
• Coagulation: "Fibrinogen up 50%" — "Pregnancy = Prothrombotic" — factors VII, VIII, IX, X, XII all increase
• Albumin: "Down 10 g/L" — haemodilution → decreased plasma albumin

Fetal Circulation

• Blood flows: Umbilical vein → Ductus venosus → IVC → RA → Foramen ovale → LA → Aorta → Brain; SVC → RA → RV → Ductus arteriosus → Aorta → Body
• Key: "Oxygenated blood in the umbilical VEIN goes to the brain. Deoxygenated blood goes to the placenta via umbilical ARTERIES."

Lactation

• Prolactin: "PR for 'Produce milk'" — prolactin stimulates milk production
• Oxytocin: "OT for 'Out milk'" — oxytocin stimulates milk ejection/letdown
• After delivery: Oestrogen and progesterone drop → prolactin unopposed → lactation begins
• Breastfeeding inhibits ovulation: "Prolactin suppresses GnRH → no LH surge → no ovulation"

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5. ENDOCRINOLOGY

Hypothalamic-Pituitary Axis

• Hormones by lobe: "Anterior = FLAT PiG, Posterior = AH DO"
• Anterior: FSH, LH, ACTH, TSH, Prolactin, GH
• Posterior: ADH, Oxytocin
• Prolactin inhibitor: "Dopamine — the 'Dop' in Prolactin" (dopamine suppresses prolactin)
• GnRH pulsatility: Fast (1 per 60-90 min) → LH surge; Slow (1 per 2-4 hours) → FSH
• High frequency = LH (+), Low frequency = FSH (+)

Steroidogenesis

• Pathway: Cholesterol → Pregnenolone → Progesterone → Androstenedione → Testosterone → Oestradiol
• Two-cell theory:
• Theca interna: LH → androstenedione (androgen factory)
• Granulosa: FSH → aromatase → androstenedione → oestrogen
• "Two cells: Theca makes androgens (LH), Granulosa aromatises (FSH)"

Key Hormones

• Oestrogen functions: "EGF — Epithelial growth, Endometrial proliferation, G = good cholesterol (HDL ↑), F = Fluid retention, lower FSH"
• Progesterone functions: "P for 'Pregnant, Prepare, Protect'" — thickens endometrium, relaxes smooth muscle, raises BBT, suppresses contractions
• Relaxin: "R for 'Relax the pelvis'" — relaxes pelvic ligaments, softens cervix
• hCG function: "Keeps the corpus luteum alive" — acts like LH → maintains progesterone

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6. BIOCHEMISTRY

Common Lab Values

What	Normal Value	Mnemonic
Serum sodium	135-145 mmol/L	"1-3-5 to 1-4-5"
Serum potassium	3.5-5.0 mmol/L
Serum calcium (total)	2.2-2.6 mmol/L
Serum phosphate	0.8-1.5 mmol/L
Serum magnesium	0.7-1.1 mmol/L
Random blood glucose	<11.1 mmol/L
FBG (normal)	<6.1 mmol/L
Hb in pregnancy	>10 g/dL (3rd trimester)
Platelets	150-400 × 10⁹/L
WCC	4-11 × 10⁹/L

Acid-Base

• Respiratory acidosis: ↑pCO2, ↓pH — hypoventilation
• Metabolic acidosis: ↓HCO3, ↓pH — DKA, lactic acidosis, diarrhoea
• Respiratory alkalosis: ↓pCO2, ↑pH — hyperventilation, pregnancy (progesterone)
• Metabolic alkalosis: ↑HCO3, ↑pH — vomiting, antacids
• ROME mnemonic: "Respiratory Opposite, Metabolic Equal" — in respiratory, pH and pCO2 go opposite directions; in metabolic, pH and HCO3 go same direction

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7. PHARMACOLOGY

Drug Categories in Pregnancy

• A: Safe — controlled studies show no risk
• B: No evidence of human risk (animal studies negative)
• C: Risk cannot be ruled out — use if benefit > risk
• D: Positive evidence of human risk — may still be used in life-threatening situations
• X: Contraindicated — risk clearly outweighs benefit

Mnemonics: - "A = Always safe, B = Benefits likely, C = Caution, D = Danger, X = X-tremely dangerous"

Common Drug Mechanism Mnemonics

• Oxytocin: "T for 'Tight'" — increases calcium influx in myometrium → contraction
• Magnesium sulphate: "Magic for Magnesium, Relaxes the uterus" — calcium channel blocker at NMJ
• Nifedipine: "Tocolysis with Calcium blockade" — L-type calcium channel blocker
• Atosiban: "A for Antagonist, A for Antidiuretic" — oxytocin receptor antagonist + mild ADH effect
• Carboprost: "Prostaglandin F2α → P for 'Push' (contraction)" — PGF2α analogue
• Misoprostol: "PGE1 → 'Miso-smooth'" — cervical ripening + uterine contraction
• Methyldopa: "Centrally acting — 'DOPA' makes you drowsy (sedation)" — α2 agonist
• Labetalol: "αβ blocker — 'La-La Land' = lowers BP by blocking both α and β"
• Nifedipine: "Nif-ends up in relaxation" — calcium channel blocker
• Hydralazine: "Dilated arteries" — direct arteriolar vasodilator

Tocolysis

• "Can My Nana Really Dance?":
• (C)alcium channel blockers (Nifedipine)
• (M)agnesium sulphate
• (N)itrates (GTN patch) — off-label
• (R)itodrine (β2 agonist) — withdrawn in many countries
• (D)rugs: Atosiban (oxytocin antagonist), NSAIDs (indomethacin)
• Atosiban is the ONLY licensed tocolytic in the UK for preterm labour

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8. MICROBIOLOGY

TORCH Infections

• Toxoplasmosis
• Other (Syphilis, Varicella, Parvo B19, HIV, Hep B, Zika)
• Rubella
• Cytomegalovirus (CMV)
• Herpes simplex (HSV)

Mnemonic: "TORCH — think of a torch shining light on congenital infections"

STI Classification

• Bacterial: Chlamydia, Gonorrhoea, Syphilis, Chancroid, Granuloma inguinale, LGV
• Viral: HSV, HPV, HIV, Hep B
• Parasitic: Trichomonas, Pubic lice, Scabies
• Fungal: Candida

Alphabet key: "C G S" = Chlamydia (most common), Gonorrhoea (gram - diplococcus), Syphilis (Treponema pallidum)

Common Pathogens in O&G

• GBS (Group B Streptococcus): "B for Baby — causes neonatal sepsis"
• E. coli: Most common cause of UTI in pregnancy
• Chlamydia: Most common STI in UK — "Silent infection = PID → tubal factor infertility"
• T. vaginalis: "Itchy, frothy, green discharge — 'Trich' makes you scratch"
• Candida: "Thick, white, cottage cheese — C for Curd"
• BV (Gardnerella): "Fishy smell = BV, clue cells = clue"

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9. IMMUNOLOGY

• First line defence: Skin, mucous membranes, stomach acid, commensals
• Innate immunity: Macrophages, neutrophils, NK cells, complement — "Fast but non-specific"
• Adaptive immunity: B cells (antibodies) + T cells (cellular) — "Slow but specific + memory"
• IgG crosses placenta: "G = Goes across" (only Ig that crosses)
• IgA in breast milk: "A = Alimentary" (secretory IgA)
• Rh mismatch: Rh- mother, Rh+ baby → anti-D given at 28 weeks + within 72h of delivery
• HLA-G: "G for 'Good tolerance'" — expressed by trophoblast, protects foetus from NK cell attack

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10. PATHOLOGY

Cell Injury

• Reversible: Cellular swelling, fatty change
• Irreversible: Nuclear changes (pyknosis → karyorrhexis → karyolysis) = necrosis
• Necrosis types: "Liquefactive (brain), Coagulative (heart/kidney — most common), Caseous (TB), Fat necrosis (breast/pancreas), Fibrinoid (vessels)"
• Apoptosis: "Programmed cell death — no inflammation (unlike necrosis)"
• Metaplasia: "One adult cell type replaces another — reversible"
• Dysplasia: "Disordered growth — pre-malignant"

Tumour Markers

Tumour	Marker	Mnemonic
Ovarian epithelial (serous)	CA-125	"CA (Cancer) 125 → Ovary 125"
Gestational trophoblastic	β-hCG	"hCG = Human Chorionic = Trophoblast"
Ovarian germ cell (dysgerminoma)	LDH	"LDH = Large Dysgerminoma High"
Ovarian yolk sac	AFP	"Yolk = AFP (like foetal)"
Choriocarcinoma	β-hCG	"↑↑↑β-hCG"
Granulosa cell tumour	Inhibin	"Inhibin inhibits ... ovarian tumour"
Sertoli-Leydig	Testosterone	"Sertoli Makes Testosterone"

WHO Classification of Ovarian Tumours (Simplified)

• Surface epithelial: Serous, Mucinous, Endometrioid, Clear cell, Brenner — "SME CB"
• Germ cell: Dysgerminoma, Yolk sac, Teratoma, Choriocarcinoma — "DYT C"
• Sex cord stromal: Granulosa, Thecoma, Fibroma, Sertoli-Leydig — "GTFSL"
• Metastatic: Krukenberg (from stomach, signet ring cells) — "K for Krukenberg = Gastric"

FIGO Staging (Key Ones)

• Cervical cancer FIGO: "1 = Confined to cervix, 2 = parametrial, 3 = pelvic wall/vagina lower ⅓/renal, 4 = bladder/rectum/beyond"
• Endometrial cancer FIGO: "1 = Uterus, 2 = Cervical stroma, 3 = Serosa/adnexa/vagina/lymph nodes, 4 = Bladder/bowel/distant"
• Ovarian cancer FIGO: "1 = Ovaries, 2 = Pelvis, 3 = Peritoneum beyond pelvis/lymph nodes, 4 = Distant (liver, spleen, pleural effusion)"

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11. STATISTICS & EPIDEMIOLOGY

Study Hierarchy

• Strength of evidence: "SRMCC" — Systematic review > RCT > Cohort > Case-control > Cross-sectional > Case series > Expert opinion
• Study designs — remember: "RCT → is it effective? Cohort → what happens? Case-control → what caused it?"

Screening

• Sensitivity: "S = SnNout" — highly Sensitive test when Negative rules OUT disease
• Specificity: "P = SpPin" — highly Specific test when Positive rules IN disease
• PPV depends on prevalence: "PPV up when prevalence up" — more disease in population → more true positives
• LR+: ">10 = large change in probability (rule IN)"
• LR-: "<0.1 = large change in probability (rule OUT)"

Formulae

Measure	Formula	Mnemonic
Sensitivity	TP/(TP+FN)	"SEN = TP/(TP+FN) — Sen-sitive = TP over sick people"
Specificity	TN/(TN+FP)	"SP = TN/(TN+FP) — Specific = TN over healthy people"
PPV	TP/(TP+FP)	"PPV = TP/(TP+FP) — think: how many positives are true?"
NPV	TN/(TN+FN)	"NPV = TN/(TN+FN) — think: how many negatives are true?"
Prevalence	(TP+FN)/Total	"Total cases / Total population"
Incidence	New cases / Person-time	"New cases over time"
Odds Ratio	(ad)/(bc)	"(a × d) ÷ (b × c) in 2×2 table"
Relative Risk	a/(a+b) ÷ c/(c+d)	"Risk in exposed ÷ Risk in unexposed"
ARR	CER - EER	"Absolute Risk Reduction = Control event rate - Experimental event rate"
NNT	1/ARR	"Number Needed to Treat = 1/ARR"
NNH	1/ARI	"Number Needed to Harm = 1/ARI"

Statistical Tests — When to Use

Comparison	Parametric	Non-parametric
2 independent groups	Unpaired t-test	Mann-Whitney U
2 paired groups	Paired t-test	Wilcoxon signed-rank
3+ groups	ANOVA	Kruskal-Wallis
Categorical	Chi-square	Fisher's exact (small n)
Correlation	Pearson	Spearman's rank

P-value: "P < 0.05 = 5% chance results due to random variation alone" — "98% p"

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12. BIOPHYSICS & IMAGING

Ultrasound Physics

• Piezoelectric effect: "PZ → Pressure = Electricity" — crystals deform ↔ electrical signal
• Frequency vs Resolution: "Higher frequency = Higher resolution BUT Lower penetration"
• Acoustic impedance: the bigger the difference, the more reflection: Air-soft tissue = huge reflection → black shadow (bowel gas)
• Doppler equation: Δf = 2f₀v(cosθ)/c — shift proportional to velocity
• Doppler angle: "Get angle <60° for accuracy" — cos 60° = 0.5; above 60° → inaccurate

CTG

• Baseline: 110-160 bpm
• Variability: 5-25 bpm = normal
• Accelerations: ≥15 bpm × ≥15 sec (≥32 wks); ≥10 bpm × ≥10 sec (<32 wks)
• Early decelerations: Head compression → vagal → mirror contraction
• Late decelerations: Uteroplacental insufficiency → "Late = Bad"
• Variable decelerations: Cord compression → "V for Variable = Vagal response to Cord"

FIGO Classification: - Normal: All features reassuring - Suspicious: 1 non-reassuring feature - Pathological: ≥1 abnormal feature OR abnormal baseline + absent variability

Radiation

• ALARA: As Low As Reasonably Achievable
• Radiation doses: CXR = 0.02 mSv → CT pelvis = 10 mSv → Fetal risk significant at >100 mSv
• LMP rule: "10-day rule" — X-ray only within first 10 days of cycle if pregnancy possible
• MRI: No ionising radiation. Contraindications: pacemakers, cochlear implants, some metal clips. Gadolinium crosses placenta → avoid in pregnancy

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13. CLINICAL & SURGICAL

Laparoscopy

• Veress needle insertion: "In the umbilicus, at 45° (non-obese) to 90° (obese). 2 clicks = fascia + peritoneum"
• Palmer's point: "Left upper quadrant - 3cm below costal margin, mid-clavicular line" — used for patients with previous midline laparotomy
• Entry complications: "Bowel (most dangerous), Bladder, Vessel (epigastric/iliac)"
• Gas: CO₂ — "absorbs quickly, non-flammable, dissolves in blood"

Hysteroscopy

• Distension media: "Normal saline for diagnostic, Glycine for operative (monopolar)"
• Complications: "Fluid overload → pulmonary oedema → hyponatraemia (with glycine)"

Surgical Principles

• Wound classification: "Clean (C-section), Clean-contaminated (hysterectomy), Contaminated (PIH bowel injury), Dirty (abscess)"
• Suture types: "Vicryl = Braided, Absorbable, 60-90 days; PDS = Monofilament, Absorbable, 180 days; Nylon = Non-absorbable"
• Sutures — remember: "Absorbable (Vicryl, PDS, Monocryl), Non-absorbable (Nylon, Prolene, Silk)"
• Needle types: "Round body = soft tissue; Cutting = skin; Tapercut = tough tissue (cervix)"

Common Procedures

• Caesarean section: "LSCS — 7 layers: Skin, Fat, Rectus sheath, Muscle separation, Peritoneum, Uterus, Membranes"
• Episiotomy: "Mediolateral — angle 60° from midline to the right — avoid injury to Bartholin's gland and anal sphincter"
• Third stage management: "Active management → Oxytocin 5-10 IU IM → Controlled cord traction"

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Final tip: Don't try to memorise all these in one sitting. Use the topic tabs in your weak-topic tracker to decide which set of mnemonics to review each day. The mnemonics that stick best are the ones you make yourself — if you have a better mnemonic, use it!

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