Obstetrics and Gynaecology
What is tested
Obstetrics dominates: antenatal dating, hypertensive disease, labor and its complications, postpartum hemorrhage and contraception. Gynecology adds PCOS, fibroids, endometriosis and cervical screening.
Core rules
- Naegele's rule: expected date of delivery = first day of last menstrual period + 9 months + 7 days.
- GDM screening: 75 g OGTT at 24–28 weeks; thresholds fasting ≥92, 1 hour ≥180, 2 hours ≥153 mg/dL (any one abnormal).
- Preeclampsia: blood pressure ≥140/90 after 20 weeks plus proteinuria or maternal organ dysfunction. Severe features include ≥160/110, platelets <100,000/µL, transaminases doubled, creatinine >1.1 mg/dL, pulmonary edema, and visual or cerebral symptoms.
- Magnesium sulfate prevents and treats eclamptic seizures. Monitor deep tendon reflexes, respiratory rate ≥12/min and urine output ≥30 mL/h; calcium gluconate is the antidote.
- Postpartum hemorrhage: tone, trauma, tissue, thrombin. Uterine atony is commonest; begin massage and oxytocin.
Worked example
A woman at 34 weeks has BP 168/112 mmHg, 3+ proteinuria, headache and platelets 88,000/µL. Reasoning: severe preeclampsia with thrombocytopenia and cerebral symptoms. She needs intravenous magnesium sulfate for seizure prophylaxis, antihypertensives (labetalol or nifedipine) to keep BP below 160/110, and delivery - the only definitive treatment - after antenatal steroids if time permits.
Traps
Using magnesium as an antihypertensive (it is not); prescribing ACE inhibitors in pregnancy; and forgetting that eclampsia can present in the postpartum period with a previously normal blood pressure.