In which circumstance is GBS prophylaxis not recommended according to AAP and CDC guidelines?

GBS prophylaxis is not recommended in the case of a planned cesarean birth with intact membranes and a previous positive GBS screen. This is because the guidelines stipulate that if a cesarean delivery is planned in the absence of labor and with the membranes still intact, the risk of vertical transmission of Group B Streptococcus (GBS) to the newborn is significantly reduced. In such situations, the mother is less likely to pass the bacteria during delivery, rendering prophylaxis unnecessary.

In other circumstances, such as GBS bacteriuria during the current pregnancy, prophylaxis is advised because this indicates a high colony count that can result in transmission during labor and delivery. Likewise, if a mother has a previous history of multiple preterm births, GBS prophylaxis is recommended because preterm infants are already at an increased risk for complications, and preventing potential GBS transmission is critical. Additionally, if a mother has a negative GBS screen in the current pregnancy but has a history of a previous infant with known GBS infection, prophylaxis is essential to protect subsequent infants from the risks associated with GBS colonization.