Obstetrics and Gynecology
Core concepts
OB/GYN questions span antenatal care, labor, and gynecologic pathology. Know the schedule of prenatal visits and screening (first-trimester dating ultrasound, aneuploidy screening, gestational diabetes screening at 24–28 weeks), the stages of labor, and fetal monitoring interpretation (baseline rate, variability, accelerations, decelerations). Understand hypertensive disorders of pregnancy - gestational hypertension, preeclampsia (after 20 weeks with proteinuria or organ dysfunction), eclampsia, and HELLP syndrome - and postpartum hemorrhage causes (the "4 T's": tone, trauma, tissue, thrombin).
Common traps
Timing is everything: preeclampsia is defined after 20 weeks; before that, consider molar pregnancy or other causes. Distinguish early decelerations (head compression, benign) from late (uteroplacental insufficiency) and variable (cord compression) decelerations. Questions bait with magnesium sulfate: it prevents and treats seizures in preeclampsia/eclampsia but is not an antihypertensive. In gynecology, know cervical cancer screening intervals and the difference between abnormal bleeding from anovulation versus structural causes.
Worked example
A 34-week pregnant woman with BP 160/110, headache, and 3+ proteinuria. Rule of thumb: severe features (BP ≥160/110, symptoms, lab abnormalities) mandate delivery consideration plus magnesium sulfate for seizure prophylaxis and antihypertensives (e.g., labetalol, hydralazine).
Rule of thumb
In pregnancy, always ask gestational age first - it determines whether a finding is normal, a screening indication, or an emergency.