When should Group B Streptococcus (GBS) screening occur in pregnancy?

Group B Streptococcus (GBS) screening in pregnancy is typically recommended to occur between 35 and 36 weeks of gestation. This timing is crucial because it allows for the identification of GBS colonization in the mother, which can then guide the appropriate management to reduce the risk of vertical transmission to the baby during delivery.

Screening at this stage is optimal because GBS colonization can change throughout the course of pregnancy. Testing too early, such as at 28-30 weeks, may not accurately reflect the colonization status closer to delivery. Conversely, testing too late, such as immediately after delivery, does not allow for timely intervention to administer prophylactic antibiotics if needed during labor. Therefore, screening during the 35-36 week window ensures that healthcare providers can implement strategies to protect the newborn while still allowing enough time to respond to the results effectively.