Obstetrics & Gynecology — USMLE Step 3 Practice
Obstetrics and gynecology on USMLE Step 3 covers prenatal care, obstetric emergencies, labor management, gynecological cancers, and contraception. Recognizing maternal emergencies and fetal distress patterns are high-yield topics.
Frequently Asked Questions
What are the diagnostic criteria for preeclampsia on USMLE Step 3?
Preeclampsia: BP ≥140/90 on two occasions ≥4 hours apart after 20 weeks gestation with proteinuria (>300 mg/24h or PCR >0.3), or severe features (BP ≥160/110, thrombocytopenia <100K, renal insufficiency, pulmonary edema, new-onset headache, visual disturbances). Definitive treatment: delivery. Magnesium sulfate for seizure prophylaxis in severe preeclampsia.
How do you manage shoulder dystocia on Step 3?
Call for help immediately. McRoberts maneuver (hyperflexion of maternal thighs) + suprapubic pressure first. If unsuccessful: rotational maneuvers (Rubin II, Woods screw), delivery of posterior arm, Zavanelli maneuver (cephalic replacement + cesarean) as last resort. Document 'turtle sign.' Avoid fundal pressure (worsens impaction).
What is the Step 3 screening schedule in pregnancy?
First trimester (10-13 weeks): cell-free fetal DNA (NIPT) or nuchal translucency + PAPP-A + beta-hCG. 15-20 weeks: quad screen (AFP, hCG, inhibin A, estriol). 24-28 weeks: 1-hour GCT (glucose challenge test) — if ≥140 mg/dL, do 3-hour GTT. 35-37 weeks: GBS culture. Anatomy ultrasound at 18-20 weeks.
How do you classify and manage postpartum hemorrhage?
PPH: >500 mL blood loss after vaginal delivery (>1000 mL after C-section). Causes: '4 Ts' — Tone (uterine atony, 80%), Trauma (lacerations), Tissue (retained placenta), Thrombin (coagulopathy). Management: bimanual uterine massage, oxytocin IV, methylergonovine (avoid in hypertension), carboprost (avoid in asthma), misoprostol, tranexamic acid. Surgical options if medical management fails.
What is the management of ectopic pregnancy on Step 3?
Ectopic pregnancy: unruptured + stable + meeting criteria → methotrexate (single-dose IM). Criteria for methotrexate: gestational sac <3.5 cm, no fetal cardiac activity, beta-hCG <5,000 mIU/mL, no contraindications (liver disease, renal disease, blood dyscrasia). Ruptured or hemodynamically unstable → emergency surgery (laparoscopic salpingectomy).
Related Articles
- High-Yield OB/GYN for USMLE Step 3: Preeclampsia, Labor, and Postpartum Hemorrhage
Master OB/GYN for USMLE Step 3 — preeclampsia criteria, labor management, postpartum hemorrhage 4Ts, ectopic pregnancy, and prenatal screening schedules.
Ready to practice?
0 exam-style Obstetrics & Gynecology questions — free, no account required.
Practice Obstetrics & Gynecology Questions