This document does not introduce important changes from the CDC guidelines. The key measures necessary for preventing neonatal GBS early onset disease continue to be universal prenatal screening by culture of GBS from swabs collected from the lower vagina and rectum, correct collection and microbiological processing of the samples, and proper implementation of intrapartum antibiotic prophylaxis. It is also important to note that the ACOG recommended performing universal GBS screening between 36 and 37 weeks of gestation. This new recommendation provides a 5-week window for valid culture results that includes births that occur up to a gestational age of at least 41 weeks.