Preterm prelabor rupture of membranes in singletons: maternal and neonatal outcomes.

Objectives: To determine the effect of gestational age at delivery on maternal and neonatal outcomes in preterm prelabor rupture of membranes (PPROM) and assess various predictors of neonatal and infant mortality in these pregnancies.

Methods: United States birth data from CDC-National Center for Health Statistics natality database for years 2004-2008 was used to identify singleton pregnancies with PPROM and delivery from 32 0/7 to 36 6/7 weeks. Controls were singletons at 37-40 weeks, without PPROM. Maternal and neonatal complications reported by all states were analyzed along with neonatal outcomes such as chorioamnionitis and hyaline membrane disease, reported by a subgroup of states. OR (95% CI) were calculated after adjusting for preeclampsia, diabetes, chronic hypertension, maternal race, and infant sex.

Results: There were 134,502 PPROM cases and similar number of controls. There was a significant decrease in need for prolonged ventilation, hyaline membrane disease, 5 min Apgar score <7, and NICU admission with advancing gestational age. Placental abruption decreased and chorioamnionitis and cord prolapse were not different between 34 and 37 weeks. We found reductions in early death, neonatal death, and infant mortality with advancing gestational age (p<0.001 for each). Gestational age at delivery was the strongest predictor for early death, neonatal death, and infant mortality in PPROM. These differences persisted after adjusting for antenatal steroid use.

Conclusions: We provide population-based evidence showing a decrease in neonatal complications and death with advancing gestational age in PPROM. Gestational age at delivery in pregnancies with PPROM is the strongest predictor of mortality risk.