Neonatal morbidity associated with maternal Group B Streptococcal colonization in individuals undergoing planned...

To examine the association between unknown maternal Group B Streptococcal (GBS) colonization and the risk of severe neonatal morbidity among individuals undergoing planned cesarean delivery.

We performed a secondary analysis of a multicenter, prospective observational study of individuals with singleton gestations and planned cesarean delivery ≥37 weeks gestation with cervical dilation ≤3 cm, intact membranes, and no evidence of labor or induction. GBS status was categorized as positive, negative, or unknown. The primary outcome was a composite of severe neonatal morbidity, including clinical or culture-proven sepsis, ventilator support in the first 24 h, respiratory distress syndrome, hypotension requiring treatment, intubation, necrotizing enterocolitis, hypoxic-ischemic encephalopathy, or death. We compared individuals with unknown GBS status to those with positive and negative GBS status.

In this cohort, 4,963 individuals met inclusion criteria; 72% had unknown GBS status, 25% were GBS negative and 3% were GBS positive. Among individuals with unknown GBS status, 208 (5.9%) had the primary composite neonatal outcome, compared with 75 (6%) of GBS negative individuals and 6 (4%) of GBS positive individuals. There was no difference in composite severe neonatal morbidity among GBS unknown, GBS negative, and GBS positive individuals (5.9% vs 6% vs 4%, p = .61). After adjusting for male sex and intrapartum antibiotic exposure, unknown GBS status was not associated with severe neonatal morbidity (adjusted risk ratio, 0.95; 95% confidence interval, 0.73-1.22).

GBS status at time of planned cesarean delivery does not appear to be associated with composite severe neonatal morbidity. The cost effectiveness and clinical utility of GBS screening among individuals undergoing planned cesarean delivery requires further investigation.