Preterm premature rupture of membranes and the associated risk for placental abruption. Inverse correlation to gestational length.

OBJECTIVE: To evaluate the association between prolonged premature rupture of membranes (PROM) and placental abruption, especially during midtrimester pregnancy. METHODS: A retrospective hospital based study of 83 women with PROM occurring between 14 and 32 weeks of gestation and where active expectant management was undertaken. RESULTS: Increased frequency of placental abruption was found in patients with early rupture of membranes. The incidence was 50% and 44% when rupture of the membranes occurred before 20 weeks or between 20-24 weeks of pregnancy, respectively. When PROM occurred during gestational ages of 29-32 weeks, the incidence was 13%. Patients with antepartum bleeding, both before (relative risk 34) and after rupture of the membranes (relative risk 38) had a significantly higher risk for placental abruption (p<.001) than women without bleeding prior to delivery. The overall neonatal survival rate was 87%. No neonatal deaths were considered to be directly caused by asphyxia due to placental abruption. CONCLUSION: Using active expectant management and strict routines it seems possible to minimize the risk for perinatal asphyxia and mortality. The clinician should be aware of the significant association between preterm premature rupture of membranes and the risk for subsequent placental abruption, especially in patients with early midtrimester PROM and history of bleedings before rupture of membranes or bleedings during the latency period.