(603) Group B streptococci colonization and the expectant management of late preterm prelabor rupture of membranes

Objective: The impact of maternal group B streptococci (GBS) colonization on outcomes of expectant management of late premature prelabor rupture of membranes (PPROM) is controversial. We explored maternal and neonatal infectious outcomes in women who presented with PPROM at 34-36.6 weeks according to GBS colonization status.

Study Design:
This retrospective cohort study included 412 women who presented with late PPROM and were admitted for expectant management. Outcomes were compared according to positive GBS status (n=73) and negative GBS status (n=339). The co-primary outcomes were clinical chorioamnionitis and latency duration (ROM-delivery duration). Expectant management consisted of betamethasone administration and 7-day antibiotics regimen. Induction was performed at 37 weeks or earlier if chorioamnionitis or non-reassuring fetal status was suspected. After delivery, chorioamniotic swabs were obtained. The required sample size was calculated to be at least 398, considering a 10% effect size in the rate of women with latency > 48 hours, with a power of 80% and an alpha of 5%.

Results:
Gestational age at PPROM was similar between the groups (Table). The rates of intrapartum fever, clinical chorioamnionitis, postpartum fever, latency duration, latency >48 hours, and delivery week were similar. For the positive vs. negative GBS status group, antibiotic administration in the neonatal intensive care unit was more common: 11.1% vs 3.5%, p=0.013. Rates of neonatal complications such as early onset sepsis, respiratory distress syndrome, invasive ventilation, and meconium aspiration syndrome were similar between the groups. The distributions of pathogens in chorioamniotic swab cultures were similar (p=0.461) (Figure).

Conclusion:
Among women with PPROM at 34-36.6 weeks, we report similar maternal and neonatal adverse outcomes. The increased neonatal antibiotic administration may be attributed to preventive measures related to the positive GBS status. Expectant management of PPROM in women with GBS colonization is reasonable.