Risk factors for pulmonary hypoplasia in second-trimester premature rupture of membranes

OBJECTIVE: Our purpose was to determine the independent contribution of gestational age at rupture of membranes, latency period, and severity of oligohydramnios to the prediction of pulmonary hypoplasia in patients with second-trimester premature rupture of membranes. STUDY DESIGN: All women with premature rupture of membranes at <28 weeks diagnosed between January 1982 and December 1990 were managed conservatively with a consistent protocol until intrauterine death or spontaneous or induced delivery. The diagnosis of pulmonary hypoplasia was made by strict pathologic and radiographic criteria. RESULTS: A total of 63 patients fulfilled the inclusion criteria. Pulmonary hypoplasia was present in 15 cases: two of nine stillborns, 12 of 25 neonatal deaths, and one of 24 survivors. All fetuses with pulmonary hypoplasia had oligohydramnios. Univariate analysis showed that the occurrence of pulmonary hypoplasia was significantly associated with gestational age at premature rupture of membranes (p = 0.002), oligohydramnios during the latency period (p = 0.005), and duration of the latency period (p = 0.02). However, logistic regression analysis showed that only the first two variables were independent predictors of pulmonary hypoplasia. CONCLUSION: Gestational age at premature rupture of membranes and oligohydramnios are independent predictors of the occurrence of pulmonary hypoplasia.