(294) Understanding Maternal Infection in Late Preterm Prelabor Rupture of Membranes by Time of Ruptured Membranes

Objective: Expectant management (EM) of late preterm PPROM is thought to improve neonatal outcomes without increasing the risk of neonatal sepsis. European clinical trials have described the median duration of EM as ~3-4 days, and suggest increased risk of maternal infection with EM. However, more data are required to corroborate these findings in a US population and to stratify risk based on time of rupture of membranes (ROM). We investigated the association between the length of time from ROM to delivery and maternal infection after PPROM between 34-36 weeks.

Study Design: Secondary analysis of RCT of singleton pregnancies at risk for preterm delivery between 34-36 weeks. Parent trial included subjects with PPROM occurring ≥34 weeks without signs of infection/plan for induction at ≤12 hours. Primary outcome, maternal infection composite (chorioamnionitis +/- endometritis), was compared in participants with ROM < 1 day ( < 24 hours), between 1- < 2 days (24- < 48 hours), and ≥2 days (≥48 hours). Secondary outcomes: mode of delivery and selected neonatal outcomes.  Baseline characteristics were compared between groups; multivariable logistic regression models were fit to control for confounders

Results: Of 620 individuals with PPROM, 31 (5.0%) had maternal infection: 2.3% of individuals with ROM < 1 day, 7.8% with ROM between 1-2 days, and 6.8% in those with ROM ≥ 2 days (p=0.01, Figure 1). Participants with maternal infection had significantly more time with ROM. After adjusting for confounders, ROM between 1-2 days and ≥ 2 days was significantly associated with maternal infection compared to ROM < 1 day (Table).  Cesarean delivery, neonatal sepsis, and NICU admission were more common with increasing time from ROM. Neonatal respiratory outcomes were not different between groups.

Conclusion: Maternal infection and cesarean delivery rates increased with time after ROM. Increasing time was associated with neonatal sepsis and provided no short-term respiratory benefits with a trend towards greater NICU admission. Our findings prompt further evaluation of delivery delay after late preterm PPROM in a larger US population.