Twin versus singleton pregnancies complicated by preterm premature rupture of membranes.

Objective: To compare latency period, infectious morbidity, neonatal morbidity and neonatal mortality in twin versus singleton pregnancies complicated by preterm premature rupture of membranes (PPROM) remote from term.

Methods: A retrospective, matched cohort study comparing 41 twin and 82 singleton pregnancies complicated by PPROM between 24-0/7 and 31-6/7 weeks' gestation. The data were obtained by reviewing maternal and neonatal charts.

Results: The median latency periods were 3.6 days (interquartile range 1.5-13.9 days) for twins and 6.2 days (interquartile range 2.9-11.8 days) for singletons (p = 0.86). Twins were less likely to be complicated by clinical chorioamnionitis when compared with singletons (4/41 [9.8%] vs. 19/82 [23.2%], relative risk [RR] 0.42, 95% confidence interval [CI] 0.18-0.96). Histological evidence of chorioamnionitis was also lower in twins compared with singletons (14/39 [35.9%] vs. 46/68 [67.7%], RR 0.56, 95% CI, 0.34-0.92). These differences persisted after adjusting for race, insurance status, latency period and route of delivery. Neonatal morbidity and mortality rates were similar between the two groups.

Conclusions: There was not a statistically significant difference in the latency periods for twin and singleton pregnancies complicated by PPROM. Clinical chorioamnionitis and histological evidence of infection were significantly less common in twins compared with singletons.