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Group B streptococcus screening — USMLE Step 3 MCQ

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ModerateOB/GYN (prenatal care, contraception, screening)Group B streptococcus screeningUSMLE Step 3

A 30-year-old pregnant patient at 36 weeks' gestation has an uncomplicated pregnancy. She has no penicillin allergy and no prior infant with group B streptococcal disease. Which of the following is the most appropriate screening recommendation?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: C — Obtain vaginal-rectal group B streptococcus culture

Universal vaginal-rectal GBS screening is performed at 36 0/7 to 37 6/7 weeks' gestation unless prophylaxis is already indicated.

Reference: ACOG group B streptococcal disease prevention guidance