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GBS prophylaxis — USMLE Step 3 MCQ

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ModerateOB/GYN (prenatal care, contraception, screening)GBS prophylaxisUSMLE Step 3

A 30-year-old woman at 39 weeks is in labor. Prenatal rectovaginal culture at 36 weeks was positive for group B streptococcus. She has no penicillin allergy. Membranes ruptured 2 hours ago and she is afebrile. Which of the following is the most appropriate next step in management?

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Correct answer: B — Give intrapartum IV penicillin G

Positive GBS screening culture in late pregnancy requires intrapartum antibiotic prophylaxis to prevent neonatal early-onset GBS disease.

Reference: ACOG Group B Streptococcus Prevention Guidance