Neonatal morbidity at 34-37 weeks: the role of ruptured membranes

Evaluate neonatal morbidity in deliveries occurring between 34 0/7 and 36 6/7 weeks' gestation, comparing outcomes in pregnancies complicated by preterm premature rupture of membranes with those in which delivery occurred with intact membranes prior to the onset of labor.

The obstetric database was reviewed for a 5-year period. Healthy gravidas delivering nonanomalous singleton gestations from vertex presentations were evaluated, with corticosteroid or antibiotic administration or both noted. The neonatal database was reviewed for the following complications: admission to the neonatal intensive care unit, need for assisted ventilation, and development of hyaline membrane disease, bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, or culture-proven sepsis. Groups were compared using chi2 tests. The power of this study to detect a ten-fold decrease in the likelihood of neonatal complications at the P<.05 significance level was greater than 90%.

Of 853 eligible pregnancies, 414 (48.5%) gravidas had ruptured membranes prior to the onset of active labor. No difference existed between groups in the number of patients who had received corticosteroids during pregnancy, but patients with ruptured membranes were more likely to have received antibiotics prior to delivery. No neonatal deaths occurred, and neonatal morbidity was low in both groups.

No clinically significant difference exists in neonatal outcome between 34 0/7 and 36 6/7 weeks' gestation as the result of membrane status prior to the onset of labor.