Master Women’s Health (Obs & Gyn)
for AMC Cat 1

What the AMC Cat 1 Tests in Women’s Health (Obs & Gyn)

The AMC Cat 1 exam tests Women’s Health (Obs & Gyn) through clinical vignettes requiring diagnosis, management, and risk stratification. Candidates must demonstrate knowledge of antenatal care (screening for gestational diabetes using 75g OGTT at 24-28 weeks; first-trimester combined screening for Down syndrome), intrapartum emergencies (shoulder dystocia: McRoberts manoeuvre, suprapubic pressure; postpartum haemorrhage: first-line oxytocin 5 IU IV, then ergometrine 0.5 mg IV or carboprost 250 mcg IM), gynaecological presentations (abnormal uterine bleeding: PALM-COEIN classification; endometriosis: first-line combined oral contraceptive or progestins; ovarian cysts: risk of malignancy index RMI >200 warrants referral), and contraception (LARC: Mirena IUS for menorrhagia, copper IUD for emergency contraception up to 5 days). Emphasis is on evidence-based guidelines (RCOG, NICE, WHO) and safe prescribing in pregnancy (avoid NSAIDs after 28 weeks, ACE inhibitors throughout).

High-Yield Concepts

• Gestational Diabetes Mellitus (GDM) Screening: Screen all pregnant women at 24-28 weeks using 75g OGTT. Diagnostic thresholds: fasting ≥5.1 mmol/L, 1-hour ≥10.0 mmol/L, 2-hour ≥8.5 mmol/L (any one abnormal). First-line management: lifestyle modification and self-monitoring of blood glucose (targets: fasting <5.3 mmol/L, 1-hour postprandial <7.8 mmol/L). If inadequate, start metformin or insulin.
• Postpartum Haemorrhage (PPH) Protocols: Primary PPH: blood loss >500 mL vaginal or >1000 mL caesarean. Active management of third stage: oxytocin 10 IU IM immediately after birth. For atonic PPH: oxytocin 5 IU IV slow bolus, then ergometrine 0.5 mg IV (contraindicated in hypertension), then carboprost 250 mcg IM (asthma caution). Massive transfusion protocol if ongoing bleeding: 1:1:1 ratio PRBC:FFP:platelets.
• Shoulder Dystocia: Recognised by turtle neck sign and failure of gentle downward traction. First-line: McRoberts manoeuvre (hyperflexion of maternal hips) and suprapubic pressure (not fundal). If fails: internal rotational manoeuvres (Rubin II, Woods screw). Last resort: Zavanelli manoeuvre (cephalic replacement) or symphysiotomy. Document head-to-body delivery time >60 seconds.
• Ectopic Pregnancy Diagnosis: Presenting with lower abdominal pain and vaginal bleeding. Diagnostic criteria: serum β-hCG >1500 IU/L with empty uterus on transvaginal ultrasound. Definitive diagnosis: laparoscopy. Medical management: methotrexate 50 mg/m² IM if unruptured, mass <35 mm, no fetal cardiac activity, β-hCG <5000 IU/L. Surgical: salpingectomy or salpingostomy.
• Abnormal Uterine Bleeding (AUB): Classify by PALM-COEIN (polyps, adenomyosis, leiomyoma, malignancy, coagulopathy, ovulatory, endometrial, iatrogenic, not yet classified). First-line investigation: transvaginal ultrasound and endometrial biopsy if >45 years or risk factors. Treatment: tranexamic acid 1 g TID for 5 days, NSAIDs (mefenamic acid 500 mg TID), or Mirena IUS for heavy bleeding.
• Ovarian Cancer Risk Stratification (RMI): RMI = ultrasound score (0-3) × menopausal status (1 premenopausal, 3 postmenopausal) × CA-125 (IU/mL). RMI >200: high risk, refer to gynaecological oncology for staging laparotomy. Ultrasound features: multilocular cyst, solid areas, bilaterality, ascites, intra-abdominal metastases.
• Pre-eclampsia Diagnosis and Management: Diagnosed by new-onset hypertension (≥140/90 mmHg) after 20 weeks with proteinuria (≥300 mg/24h) or end-organ dysfunction. Severe pre-eclampsia: BP ≥160/110 mmHg. First-line antihypertensive: labetalol 200 mg PO or hydralazine 5 mg IV. Magnesium sulfate 4 g IV loading then 1 g/hour for 24 hours for seizure prophylaxis. Deliver if ≥37 weeks or if maternal/fetal compromise.
• Contraception: LARC and Emergency: Long-acting reversible contraception (LARC): Mirena IUS (5 years) for menorrhagia, copper IUD (10 years) for emergency contraception up to 5 days post-unprotected sex. Emergency contraception: levonorgestrel 1.5 mg PO within 72 hours, or ulipristal 30 mg PO within 120 hours (more effective). Contraindications: copper IUD in Wilson disease, Mirena in active liver disease.

Common Traps in Women’s Health (Obs & Gyn) Questions

• Confusing pre-eclampsia with gestational hypertension: pre-eclampsia requires proteinuria or end-organ dysfunction, not just elevated BP.
• Using NSAIDs (e.g., ibuprofen) for pain in third trimester: they can cause premature ductus arteriosus closure and oligohydramnios after 28 weeks.
• Assuming a negative urine pregnancy test excludes ectopic pregnancy: serum β-hCG is more sensitive and quantitative for monitoring.
• Forgetting that fundal pressure is contraindicated in shoulder dystocia: it increases risk of brachial plexus injury and uterine rupture.
• Misinterpreting a single elevated BP reading as pre-eclampsia: diagnosis requires two readings ≥140/90 mmHg at least 4 hours apart or one reading ≥160/110 mmHg.
• Treating heavy menstrual bleeding with oral contraceptive pills without first excluding endometrial hyperplasia/cancer in women >45 years.

How to Revise Women’s Health (Obs & Gyn) for the AMC Cat 1

Focus on acute obstetric emergencies (PPH, shoulder dystocia, eclampsia) and gynaecological triage (ectopic pregnancy, ovarian torsion, AUB). Questions are often scenario-based: you must choose the next best step in management (e.g., 'What is the first-line drug?' or 'Which investigation is diagnostic?'). Prioritise RCOG Green-top Guidelines and NICE pathways. Practise interpreting CTG patterns (e.g., late decelerations = fetal hypoxia) and ultrasound findings (e.g., empty uterus with adnexal mass = ectopic until proven otherwise). Memorise key cut-offs: β-hCG 1500 IU/L for ectopic, RMI 200 for ovarian cancer, OGTT thresholds for GDM. Avoid over-investigating low-risk patients (e.g., young women with simple ovarian cysts <5 cm).

Practise it: MedLumen has 100 Women’s Health (Obs & Gyn) questions for the AMC Cat 1, each with a full explanation and references.