Contemporary Management of Preterm Premature Rupture of Membranes: Determinants of Latency and Neonatal Outcome

Abstract

Preterm premature rupture of membranes (PPROM) occurs in approximately 3% of all births and accounts for 30% of neonatal morbidity/mortality in premature pregnancies. In the past, a majority of women have delivered within 48 hours of presenting, but recent trials in which women received antibiotics and steroids report that 40% to 50% of them delivered a week after presentation. This retrospective study analyzed outcomes in 134 women seen at 24 to 32 weeks gestation with PPROM. They uniformly received glucocorticoids antenatally (2 12-mg intramuscular doses of betamethasone 24 hours apart or 4 6-mg doses of dexamethasone given intravenously at 12-hour intervals) and antibiotics (usually ampicillin followed by amoxicillin or ampicillin with azithromycin). The women were monitored by daily nonstress testing and twice-weekly biophysical profiles. Tocolysis was used in nearly 60% of women when regular contractions occurred for 48 hours after admission to ensure fetal exposure to steroids. Forty-three women, 32% of participants, had a latency period exceeding 1 week. On univariate analysis, the only maternal factor significantly associated with short latency was nulliparity. Bacterial vaginosis correlated with a shorter interval to delivery when intermediate, and not only positive, Gram stains were taken into account. Both mean and median latencies increased with declining gestational age. On multivariable linear regression analysis, the amniotic fluid index at admission correlated directly and significantly with latency. Gestational age and the white blood cell count at admission also were independent predictors of latency. There was a trend, although not a significant one, toward increasing intrauterine inflammation with longer latency. Funisitis did occur significantly more often when latency exceeded 1 week. There were no fetal deaths and no significant intraventricular hemorrhage after 28 weeks gestation. The finding that the risk of intrauterine inflammation increases with prolonged latency after PPROM is of concern in view of recent reports relating neonatal infection to long-term neurologic problems.