At what gestational age is Group B Streptococcus screening typically performed?

Group B Streptococcus (GBS) screening is typically performed between 35 to 37 weeks of gestation. This timing is crucial because it allows for the identification of GBS colonization in pregnant individuals as they approach delivery.

Screening at this point in pregnancy is important because the presence of GBS can lead to neonatal infections, particularly during the first week of life. The recommendation is to test during this window because it captures the most relevant period in relation to labor and delivery. Testing too early in the third trimester may not accurately reflect the GBS status at the time of delivery, as colonization can fluctuate over time.

This timing ensures that if a pregnant individual is found to be GBS positive, appropriate prophylactic antibiotics can be administered during labor to help reduce the risk of infection to the newborn. This proactive approach has been shown to significantly decrease the incidence of early-onset GBS disease in infants.