In pregnancy care, when should GBS screening be performed to reduce neonatal infection risk?

• A. 20-24 weeks
• B. 36-37 weeks
• C. 28-32 weeks
• D. 38-40 weeks

Answer: (B)

The main idea is to test for group B Streptococcus late in pregnancy so that decisions about protecting the newborn during labor can be made with an accurate picture of the mother’s status at delivery. GBS colonization can change over time, so screening close to term ensures the result reflects what the mother is likely to have when she goes into labor. The standard window of 36 to 37 weeks is used because a positive result means intrapartum antibiotics (usually penicillin G) can be given during labor to prevent early-onset GBS disease in the newborn, while a negative result generally means antibiotics aren’t needed unless other risk factors arise (like prolonged rupture of membranes or intrapartum fever). Testing earlier than this window risks the status changing before delivery, and testing after 37 weeks may not provide enough time to administer prophylaxis effectively.