(160) Outcomes associated with prolonged rupture of membranes

Objective: Prolonged rupture of membranes (ROM) can be associated with worse maternal and neonatal outcomes. However, there is no clear understanding of the linear relationship between duration of ROM during labor and adverse outcomes. We aimed to evaluate how length of ROM can affect maternal and neonatal outcomes.

Study Design: This was a secondary analysis of the MFMU network ARRIVE trial. Low-risk nulliparous were randomized to labor induction at 39 weeks versus expectant management until 42 weeks 2 days. We compared women with ROM between 6-11.9 hours (baseline) versus those who had prolonged ROM between 12-17.9 hours (group I) and 18+ hours (group II). The primary outcome was a composite maternal adverse outcome (CMAO) defined as postpartum infection, postpartum hemorrhage, chorioamnionitis, ICU admission, or uterine rupture. Our secondary outcome was the composite neonatal adverse outcome (CNAO) defined as APGAR < 3 at 5 minutes, NICU admission, seizures, sepsis, hypoxic-ischemic encephalopathy, birth injury, and neonatal death. Adjusted relative risk (aRR) with 95% confidence interval (CI) was calculated.

Results: Overall, 2199 were in the baseline group, 1117 in group I, and 743 in group II. BMI on admission, and delivery type varied among the groups. The primary outcome was significantly different between the groups when compared with the baseline group; there was a higher CMAO in Group I (aRR 1.74 CI 1.5-2.0) and group II (aRR 2.0 CI 1.7-2.4). The CNAO was also higher in Group I (aRR 1.53 CI 1.3-1.8) and Group II (aRR 2.1 CI 1.8-2.6). Length of ROM was not a predictor of CMAO or CNAO based on the area under the receiver operating characteristic curve for prolonged ROM. A logistic regression curve demonstrated for every hour of prolonged ROM increased the risk of CD by 7% (p < 0.01 CI 6.0-8.0).

Conclusion: Our secondary analysis suggests that prolonged ROM during labor, regardless of the mode of delivery, is associated with increased likelihood of CMAO and CNAO. This risk is highest among those with 18+ hours of ROM during labor.