A: Group B-Streptococcus (GBS) testing is performed between the 35th and 37th week of pregnancy, with results usually available within a week. If a patient goes into labor before the results are known (which usually means before the 37th week of pregnancy) we assume she's GBS positive and recommend treatment during labor.

If you have such a rapid delivery that you don't have time to receive antibiotics, a pediatrician will evaluate the baby and decide if treatment should be initiated. Treatment after delivery can also be an effective means of preventing GBS infection in a newborn.

Having a cesarean section doesn't eliminate the possibility of a baby developing GBS. However in certain circumstances—if the c-section is performed without labor and while the amniotic sac is intact—it will reduce the likelihood. If the amniotic sac is broken, though, bacteria—including GBS—can reach the baby and cause an infection, regardless of the type of delivery. In extremely rare cases, GBS finds its way into an unbroken amniotic sac.