Obstetrics & Gynaecology

Obstetrics & Gynaecology (OBG) is one of the four "big clinical" subjects of NEET PG and INI-CET, and arguably the highest marks-per-hour subject in the entire syllabus. Unlike Medicine or Surgery, OBG is finite, formula-driven, and repetitive: the same partograph, the same gestational diabetes cut-offs, the same cervical cancer screening algorithm, and the same staging tables come back year after year. A focused aspirant who masters the high-yield core can reliably convert 25–30 questions in NEET PG and a clutch of high-discrimination questions in INI-CET. This mother page maps the entire subject the way it is tested, group by group, with the values, associations, and traps that decide ranks.

How OBG Is Tested in NEET PG / INI-CET

Weightage and question volume

• NEET PG: OBG contributes roughly 25–32 questions (out of 200), i.e. ~13–16% of the paper. Combined with the fact that it overlaps heavily with Physiology, Anatomy (pelvis), Pharmacology (oxytocics, tocolytics), Pathology (gynae tumours) and PSM (MMR, family planning), the effective OBG footprint is even larger.
• INI-CET (AIIMS/PGI pattern): OBG is disproportionately rewarded. AIIMS loves recent guideline shifts (FIGO 2018 cervical cancer staging, FIGO ovulatory/AUB-PALM-COEIN, RANZCOG/ACOG GDM cut-offs), image-based questions (CTG tracings, hysteroscopy/laparoscopy, USG, instruments, specimens) and single-best-answer clinical vignettes with deliberately close distractors.
• High-yield clustering: Labour & partograph, antepartum haemorrhage (APH), postpartum haemorrhage (PPH), hypertensive disorders, GDM, contraception, cervical cancer screening/staging, gestational trophoblastic disease (GTD), and PCOS together account for the bulk of repeats.

Recurring question styles

Style	What it looks like	Example focus
Single-best clinical vignette	A pregnant woman with X presents with Y; next best step?	APH differentiation, PPH management ladder
Numerical / criteria	Cut-off values, scores, indices	Bishop score, GDM (DIPSI/IADPSG), AFI, BPP
Image-based	CTG, USG, instrument, specimen, laparoscopy	Late vs variable decelerations, molar "snowstorm"
Staging / classification	FIGO staging of cancers, Robson, PALM-COEIN	Cervical Ca FIGO 2018, ovarian, endometrial
Association / single-liner	Drug–condition, sign–disease	Methotrexate–ectopic, Chadwick's sign
Management-sequence	"Next step", "first-line", "drug of choice"	Eclampsia → MgSO4; PPH → oxytocin
Recent advances	New guideline / new drug	Misoprostol regimens, dolutegravir in pregnancy

The golden rule for OBG MCQs: the examiner tests the protocol, not your improvisation. Whenever a vignette asks "next step," reach for the standard guideline algorithm (RCOG/ACOG/FOGSI/WHO), not a clever alternative.

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Group 1: Obstetrics (Physiological Pregnancy)

This is the foundation group — normal physiology, diagnosis, antenatal care, and fetal surveillance. It is conceptually light but heavily examined because every higher-order question assumes you know the baseline.

Must-know high-yield topics

• Physiological changes of pregnancy: Plasma volume rises ~40–50% > RBC mass → physiological/dilutional anaemia; cardiac output rises ~30–50% (peak by 28–32 weeks, further surge in labour and immediately postpartum). Respiratory alkalosis (progesterone-driven hyperventilation), increased GFR, decreased BUN/creatinine, hypercoagulable state (rise in factors VII, VIII, X, fibrinogen; fall in protein S).
• Diagnosis & dating: β-hCG doubles ~every 48 hrs in early viable IUP. Crown-rump length (CRL) in the first trimester is the most accurate method for dating. Discriminatory zone: gestational sac should be visible on TVS at β-hCG ~1500–2000 mIU/mL.
• Antenatal care: WHO 2016 recommends a minimum of 8 antenatal contacts (a shift from the older 4-visit "focused ANC"). Folic acid 400 µg/day preconception–12 weeks (5 mg in high risk: previous NTD, anti-epileptics, diabetes). Iron-folic acid supplementation per national programme.
• Fetal surveillance: Non-stress test (NST) reactivity, Biophysical Profile (BPP) — 5 components (NST, fetal breathing, gross movement, tone, amniotic fluid volume), each scored 0/2. Amniotic Fluid Index (AFI): normal 5–25 cm; <5 oligohydramnios, >25 polyhydramnios. Doppler: umbilical artery absent/reversed end-diastolic flow = ominous.

Classic associations & values

Item	Value / association
Quickening (primigravida)	~18–20 weeks
Fundal height = umbilicus	~20–24 weeks
FHR audible (Doppler)	~10–12 weeks; (Pinard) ~18–20 weeks
Chadwick's sign	Bluish discoloration of vagina/cervix
Hegar's sign	Softening of isthmus (6–10 wk)
Goodell's sign	Softening of cervix
Total weight gain (normal BMI)	~11.5–16 kg
Symphysio-fundal height (cm)	≈ gestational age in weeks (24–36 wk)

Traps students fall for

• Confusing discriminatory zone with doubling time, or quoting the old 4-visit ANC model (now 8 contacts).
• Forgetting that CRL is best for dating in T1, while BPD/femur length take over later — and that dating should never be "re-done" once an early scan has fixed it.
• Misreading "physiological anaemia" as pathological and over-treating.

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Group 2: High-risk Pregnancy

The single richest scoring group. Examiners love hypertensive disorders, diabetes, APH, Rh isoimmunisation, and medical disorders complicating pregnancy because each carries crisp numbers and a clear management ladder.

Hypertensive disorders of pregnancy

• Definitions: Gestational HTN = BP ≥140/90 after 20 weeks without proteinuria. Pre-eclampsia = HTN + proteinuria (≥300 mg/24h or P:C ratio ≥0.3) OR HTN + end-organ involvement (thrombocytopenia, raised creatinine, raised transaminases, pulmonary oedema, cerebral/visual symptoms) even without proteinuria (ACOG modern definition — a favourite update question).
• Severe features: BP ≥160/110, platelets <1 lakh, deranged LFTs, creatinine >1.1, pulmonary oedema, persistent cerebral/visual symptoms.
• Eclampsia: seizures. MgSO4 is the drug of choice for both prevention and treatment (NOT diazepam/phenytoin — Collaborative Eclampsia Trial). Antidote = calcium gluconate. Monitor: deep tendon reflexes, respiratory rate (≥12/min), urine output (≥30 mL/hr or ≥100 mL/4h).
• Antihypertensives in pregnancy: Labetalol, nifedipine, methyldopa, hydralazine. Avoid ACE inhibitors/ARBs (fetal renal dysgenesis, oligohydramnios).
• HELLP: Haemolysis, Elevated Liver enzymes, Low Platelets — a form of severe pre-eclampsia; definitive treatment is delivery.

Diabetes in pregnancy (GDM)

Test	Method	Diagnostic cut-off
DIPSI (India, non-fasting)	75 g glucose, plasma at 2 h	≥140 mg/dL = GDM
IADPSG / WHO 2013 (fasting OGTT, 75 g)	Fasting / 1 h / 2 h	≥92 / ≥180 / ≥153 mg/dL (any one)

• Drug of choice = insulin. Metformin/glyburide are alternatives but insulin remains first-line and the safe answer. HbA1c target <6.0–6.5%.
• Macrosomia, polyhydramnios, neonatal hypoglycaemia, RDS (surfactant delay), congenital anomalies (caudal regression syndrome — most specific; cardiac/NTD more common) are classic complications.

Antepartum haemorrhage (APH)

Feature	Placenta praevia	Abruptio placentae
Bleeding	Painless, recurrent, fresh	Painful, often concealed
Uterus	Soft, relaxed, non-tender	Tense, "woody hard", tender
Fetal distress	Late/uncommon	Early/common
Shock	∝ visible blood loss	Out of proportion (concealed)
Coagulopathy/DIC	Rare	Common
Investigation	TVS (safe, accurate)	Clinical; USG may miss

• Never do a per-vaginal/digital examination in suspected praevia until placenta is localised — a classic trap.
• Couvelaire uterus (utero-placental apoplexy) is associated with abruption.

Rh isoimmunisation

• Anti-D immunoglobulin to Rh-negative non-sensitised mother at 28 weeks and within 72 hours of delivery of an Rh-positive baby; also after any sensitising event (abortion, ectopic, amniocentesis, APH, ECV).
• Kleihauer–Betke test quantifies fetomaternal haemorrhage to titrate anti-D dose. Middle cerebral artery (MCA) peak systolic velocity is the non-invasive gold standard for fetal anaemia.

Traps

• Quoting diazepam for eclampsia (wrong — MgSO4).
• Doing PV exam in praevia.
• Mixing up DIPSI (non-fasting, single value) with IADPSG (fasting OGTT, three values).
• Forgetting anti-D after any sensitising event, not just delivery.

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Group 3: Labour

A high-volume image and algorithm group. The partograph, mechanisms of labour, fetal monitoring (CTG), induction, and operative delivery are perennial.

Stages and mechanism

• Stages: First (onset to full dilatation — latent <6 cm, active ≥6 cm per modern ACOG/WHO), Second (full dilatation to delivery), Third (delivery to placental expulsion), Fourth (1 hr postpartum, watch for PPH).
• Cardinal movements: Engagement → Descent → Flexion → Internal rotation → Extension → External rotation (restitution) → Expulsion. (Mnemonic: "Every Damn Fool In Egypt Eats Raw Eggs.")
• Partograph: WHO has revised to the alert/action model and the newer Labour Care Guide (2020); the classic teaching of 1 cm/hr in active phase and the alert/action lines remains heavily tested. Crossing the action line → intervene.

CTG / fetal heart rate

Pattern	Cause	Significance
Early decelerations	Head compression	Benign, mirror contractions
Variable decelerations	Cord compression	Variable; "V/W" shaped
Late decelerations	Uteroplacental insufficiency	Ominous (most worrying)
Sinusoidal	Fetal anaemia / severe hypoxia	Ominous

• Normal baseline FHR 110–160 bpm; reassuring variability 5–25 bpm. Reduced variability + late decelerations = act.

Induction, augmentation, operative delivery

• Bishop score (≥6–8 favourable) predicts induction success — components: dilatation, effacement, station, consistency, position.
• Cervical ripening: PGE2 (dinoprostone), PGE1 (misoprostol); augmentation with oxytocin.
• Robson Ten-Group Classification is the WHO-endorsed system for auditing caesarean section rates — a recurrent recent-advance MCQ.
• Forceps vs vacuum: vacuum → cephalhaematoma, subgaleal haemorrhage; forceps → facial nerve palsy, maternal trauma. Prerequisites for instrumental delivery: fully dilated cervix, ruptured membranes, engaged head, empty bladder, adequate analgesia, known position.

Traps

• Swapping early (head) and late (uteroplacental) decelerations.
• Using misoprostol for induction in a woman with previous caesarean (risk of rupture — relatively contraindicated).
• Forgetting that active phase now begins at 6 cm, not 4 cm.

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Group 4: Gynaecology (Benign & General)

A broad group: menstrual disorders, AUB, fibroids, endometriosis, PID, prolapse, and benign ovarian/uterine pathology.

Abnormal uterine bleeding — PALM-COEIN

The FIGO PALM-COEIN classification is the framework and a guaranteed question:

• PALM (structural): Polyp, Adenomyosis, Leiomyoma, Malignancy & hyperplasia.
• COEIN (non-structural): Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified.

High-yield benign conditions

Condition	Key associations / clues
Leiomyoma (fibroid)	Most common benign uterine tumour; oestrogen-dependent; red degeneration in pregnancy; submucous → menorrhagia/infertility
Adenomyosis	Bulky, tender uterus; "venetian blind"/junctional zone thickening on MRI; multiparous
Endometriosis	Cyclical pelvic pain, dysmenorrhoea, dyspareunia, infertility; "chocolate cyst"; laparoscopy = gold standard diagnosis; "powder-burn" lesions
PID	Polymicrobial (gonococcus, chlamydia); Fitz-Hugh–Curtis (perihepatic adhesions); risk of ectopic/infertility
Genital prolapse	POP-Q staging; Pelvic Organ Prolapse; vault prolapse post-hysterectomy
Ovarian cysts	Functional vs neoplastic; dermoid (mature teratoma) most common benign germ cell

• Asherman's syndrome: intrauterine adhesions → secondary amenorrhoea/infertility, classically post-curettage. Hysteroscopy is diagnostic and therapeutic.

Amenorrhoea & menstrual physiology

• Primary amenorrhoea: no menses by 15 (with secondary sexual characters) or 13 (without). Causes: gonadal dysgenesis (Turner 45,X — most common), Müllerian agenesis (Mayer–Rokitansky–Küster–Hauser), androgen insensitivity (46,XY, female phenotype, absent uterus, testes present).
• Sheehan's syndrome: postpartum pituitary necrosis (failure of lactation = earliest sign).

Traps

• Forgetting laparoscopy is the gold standard for endometriosis (not USG).
• Confusing MRKH (46,XX, absent uterus, normal ovaries/secondary characters) with AIS (46,XY).

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Group 5: Gynae-oncology

Numbers-heavy and staging-heavy — the most "memorisation reward" group. Cervical, endometrial, ovarian cancers and GTD dominate.

Cervical cancer (most tested)

• Screening (recent shift): WHO now prioritises HPV DNA testing as the primary screen (every 5–10 years), with screening from age 30 (25 in HIV+). The older Pap (cytology) every 3 years and VIA (visual inspection with acetic acid — used in low-resource Indian programmes) still appear.
• HPV 16 & 18 cause ~70% of cervical cancers. Vaccines: bivalent, quadrivalent, and nonavalent; India's indigenous CERVAVAC (qHPV) is a hot recent-advance question. Ideal age 9–14 (two doses).
• FIGO 2018 staging (a major update): incorporates imaging and pathology, and lymph node status now upstages to IIIC (IIIC1 pelvic, IIIC2 para-aortic). Stage IA defined microscopically; IB by lesion size.
• Most common histology: squamous cell carcinoma.

Endometrial carcinoma

• Type I (endometrioid): oestrogen-dependent, peri/postmenopausal, obesity/PCOS/unopposed oestrogen/tamoxifen, good prognosis. Type II (serous/clear cell): non-oestrogen, aggressive.
• Postmenopausal bleeding = endometrial cancer until proven otherwise → endometrial biopsy. TVS endometrial thickness >4 mm (postmenopausal) warrants evaluation.

Ovarian cancer

• Most cancers are epithelial (serous most common); CA-125 marker (epithelial); AFP (yolk sac/endodermal sinus), hCG (choriocarcinoma), LDH (dysgerminoma — most common malignant germ cell), inhibin (granulosa cell). Meigs syndrome: fibroma + ascites + pleural effusion. Krukenberg tumour = bilateral metastatic (signet-ring) from GI.
• Surgical staging; spreads transcoelomically. BRCA mutation association.

Gestational trophoblastic disease (GTD)

• Complete mole: 46,XX (paternal, "diploid androgenetic"), no fetus, "snowstorm"/"bunch of grapes," markedly high β-hCG, higher malignant potential. Partial mole: triploid (69,XXX/XXY), fetal parts present.
• Follow-up with serial β-hCG; avoid pregnancy during monitoring. Choriocarcinoma is exquisitely chemosensitive (methotrexate; EMA-CO for high risk). Lung is the commonest metastatic site.

Traps

• Using old FIGO cervical staging (pre-2018, clinical only) — examiners now expect node involvement = IIIC.
• Confusing tumour markers (LDH-dysgerminoma vs AFP-yolk sac).
• Forgetting that partial moles are triploid with fetal parts.

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Group 6: Reproductive Medicine

Infertility, PCOS, ovulation induction, ART, and endocrinology. Conceptually integrated with Physiology and Pharmacology.

PCOS (Rotterdam criteria)

Diagnosis requires 2 of 3: oligo/anovulation; clinical/biochemical hyperandrogenism; polycystic ovaries on USG (≥12 follicles 2–9 mm or ovarian volume >10 mL). Insulin resistance, raised LH:FSH ratio, increased risk of endometrial hyperplasia/cancer.

• First-line ovulation induction: letrozole (now preferred over clomiphene per recent evidence — a frequent update MCQ), lifestyle/weight loss first. Metformin for insulin resistance.

Infertility workup & ART

• Evaluate both partners: semen analysis (WHO 2021 reference values), ovulation (mid-luteal progesterone), tubal patency (HSG / laparoscopy with chromopertubation), ovarian reserve (AMH, antral follicle count).
• IUI, IVF, ICSI (ICSI for severe male factor), GIFT/ZIFT (historical). OHSS (ovarian hyperstimulation syndrome) is the key ART complication — VEGF-mediated capillary leak; GnRH agonist trigger reduces risk.

Traps

• Quoting clomiphene as first-line for PCOS ovulation induction when letrozole is now preferred.
• Forgetting that male factor accounts for ~40% — always evaluate semen analysis early.

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Group 7: Contraception

A short, high-yield group with strong PSM overlap (National Family Planning Programme).

Methods and key facts

Method	Mechanism / key fact
Cu-IUCD (CuT 380A)	Effective up to 10 years; spermicidal/inflammatory; emergency use within 5 days; contraindicated in PID, distorted cavity, Wilson disease
LNG-IUS (Mirena)	Progestogen-releasing; reduces menorrhagia; ~5 years
Combined OCP	Suppress ovulation; protective against ovarian & endometrial Ca; contraindicated in migraine-with-aura, smokers >35, VTE history
POP / DMPA	Progesterone-only; safe in lactation; DMPA → reversible bone loss, delayed return of fertility
Emergency contraception	Levonorgestrel 1.5 mg within 72 h (best ASAP); ulipristal up to 120 h; Cu-IUCD most effective (5 days)
Sterilisation	Tubal ligation; vasectomy (azoospermia confirmed after ~3 months / 20 ejaculations)

• Lactational amenorrhoea method (LAM): effective only if fully breastfeeding, amenorrhoeic, and <6 months postpartum.
• MTP Act (Amendment 2021): upper limit extended to 24 weeks for special categories; opinion of one RMP up to 20 weeks, two between 20–24 weeks; Medical Boards for >24 weeks (fetal anomaly). A frequently updated legal/PSM crossover MCQ.

Traps

• Misquoting CuT 380A duration (10 years, not 5).
• Forgetting the 2021 MTP amendment limits — older texts say 20 weeks.

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Cross-subject Integration & Frequent Overlaps

OBG is the connective tissue of the clinical exam. High-yield crossovers:

• Physiology: menstrual cycle hormonal axis, pregnancy cardiovascular/respiratory changes, lactation (prolactin/oxytocin).
• Pharmacology: oxytocics (oxytocin, ergometrine, carboprost, misoprostol), tocolytics (nifedipine, atosiban, β-agonists), MgSO4, teratogens (warfarin, ACE-I, valproate, isotretinoin, thalidomide), drug categories in pregnancy.
• Pathology: gynae tumour histology, GTD karyotypes, tumour markers, molar "snowstorm."
• Microbiology: TORCH infections, GBS, HIV in pregnancy, syphilis (VDRL), congenital infections.
• PSM/Community Medicine: MMR, IMR, JSY/JSSK schemes, National Family Planning Programme, contraceptive prevalence, ANC coverage, MTP Act.
• Anatomy: pelvic anatomy, pelvic diameters (true conjugate, diagonal conjugate, obstetric conjugate), perineal/episiotomy anatomy, pudendal nerve block.
• Medicine: anaemia in pregnancy, thyroid disorders, cardiac disease (mitral stenosis worsens), epilepsy.

A classic integrated favourite: teratogen–defect pairs (warfarin → chondrodysplasia punctata/nasal hypoplasia; valproate/carbamazepine → NTD; ACE-I → renal dysgenesis; lithium → Ebstein anomaly; isotretinoin → craniofacial/CNS).

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Recent Updates & Guideline Shifts (Exam-Relevant)

Examiners (especially INI-CET) actively test what changed:

• FIGO 2018 cervical cancer staging — imaging/pathology allowed; nodal disease = stage IIIC.
• WHO HPV DNA primary screening (2021 guideline) and India's CERVAVAC indigenous HPV vaccine.
• Letrozole as first-line ovulation induction in PCOS.
• WHO 8-contact ANC model (replacing 4 visits) and Labour Care Guide (2020) / Robson classification for CS audit.
• MTP (Amendment) Act 2021 — 24-week limit, expanded categories.
• ACOG pre-eclampsia definition — proteinuria not mandatory if end-organ dysfunction present.
• Dolutegravir-based ART now preferred in pregnancy (earlier NTD concern downgraded).
• IADPSG/WHO 2013 GDM universal one-step screening debate vs Indian DIPSI.
• Antenatal corticosteroids (betamethasone/dexamethasone) and MgSO4 for fetal neuroprotection (<32 weeks) — high-yield.

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Study Roadmap

Phase 1 — Build the spine (first pass)

1. Start with normal pregnancy physiology and labour (gives the baseline for everything).
2. Move to high-risk pregnancy (HTN, GDM, APH, Rh) — the biggest scorer.
3. Then gynae-oncology (pure memorisation of staging/markers) and GTD.
4. Layer in benign gynae, reproductive medicine, contraception.

Phase 2 — Consolidate with values & tables

• Make a single sheet of cut-offs: GDM, Bishop, AFI, BPP, FHR, MgSO4 monitoring, anti-D timing.
• Drill image recognition: CTG decelerations, USG (mole, ectopic, praevia), instruments, specimens.

Phase 3 — Question practice

• Solve previous-year questions (PYQs) — OBG repeats more than any other subject. Then graded MCQ banks and grand tests under timed conditions.

Last-week revision strategy

• Days 7–4: Re-read your values/tables sheet daily; revise staging tables (cervical FIGO 2018, ovarian, endometrial) and PALM-COEIN.
• Days 3–2: Rapid PYQ revision + image flashcards (CTG, USG). Lock in management ladders: PPH (uterotonics → balloon → B-Lynch → ligation/hysterectomy), eclampsia (MgSO4), shoulder dystocia (HELPERR).
• Day 1: Only mnemonics, one-liners, and the recent-update list. Do not start new topics.

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High-Yield Mnemonics

• Cardinal movements: "Every Damn Fool In Egypt Eats Raw Eggs" — Engagement, Descent, Flexion, Internal rotation, Extension, External rotation (Restitution), Expulsion.
• Shoulder dystocia — HELPERR: Help, Episiotomy, Legs (McRoberts), Pressure (suprapubic), Enter (rotational), Remove posterior arm, Roll over.
• PPH causes — 4 Ts: Tone (atony — commonest), Trauma, Tissue (retained), Thrombin (coagulopathy).
• Pre-eclampsia severe features: think HELLP + CNS + renal + BP.
• PALM-COEIN: structural (PALM) vs non-structural (COEIN) AUB.
• TORCH: Toxoplasma, Others (syphilis/HIV/VZV), Rubella, CMV, Herpes.

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Rapid-Fire One-Liners

1. Drug of choice for eclampsia → Magnesium sulphate; antidote → calcium gluconate.
2. Most common cause of PPH → uterine atony (first uterotonic = oxytocin).
3. Most accurate method of dating in first trimester → crown-rump length (CRL).
4. Gold-standard diagnosis of endometriosis → laparoscopy ("chocolate cyst," powder-burn lesions).
5. DIPSI cut-off for GDM → 2-hour plasma glucose ≥140 mg/dL (non-fasting, 75 g).
6. Complete mole karyotype → 46,XX (paternal origin); markedly raised β-hCG, "snowstorm."
7. Most common malignant ovarian germ cell tumour → dysgerminoma (marker: LDH).
8. First-line ovulation induction in PCOS → letrozole (preferred over clomiphene).
9. Anti-D timing → 28 weeks + within 72 hours of delivery of Rh-positive baby.
10. Cu-T 380A duration → up to 10 years; emergency use within 5 days.
11. FIGO 2018 cervical Ca with nodal disease → stage IIIC (IIIC1 pelvic, IIIC2 para-aortic).
12. Late decelerations on CTG → uteroplacental insufficiency (ominous); variable → cord compression.
13. MTP Act 2021 upper limit → 24 weeks for special categories.
14. Most common benign uterine tumour → leiomyoma (fibroid); red degeneration in pregnancy.

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Master the values, internalise the algorithms, and drill the PYQs — in OBG, the examiner rewards the candidate who knows the protocol cold. This subject can be the single biggest rank-booster in your NEET PG / INI-CET preparation.