Estudio comparativo entre gestaciones finalizadas electivamente por rotura prematura de membranas y por gestación cronológicamente prolongada

BACKGROUND: To decrease maternal and fetal morbidity oftem is indicated the elective termination of pregnancy; when the cervix is unfavourable, it is possible to try to artificially reproduce these changes with exogenous prostaglandins. OBJECTIVES: Comparative evaluation of maternal and fetal results between patients in which cervical ripening is practiced with indication of premature rupture of membranes and those with prolonged pregnancy. MATERIAL AND METHOD: Historic cohorts study about pregnancies requiring cervical ripening, either for premature rupture of membranes or for gestational age > or = 41 weeks, in the "Miguel Servet" Hospital (Zaragoza, Spain), from 15/11/2005 to 15/05/2008. In all the cases dinoprostone (slow release vaginal system) was employed and the initial Bishop score was < 7. The main analysed outcomes were: intrapartum fetal heart monitoring characteristics, type of delivery, umbilical artery pH, Apgar score, hospitalization in neonatal unit requirement and time from cervical ripening start to delivery. RESULTS: Neonatal hospitalization was significantly more frequent in the ruptured membranes cohort (11.70% vs 2.33%); p = 0.001. This difference could be justified by gestational age (OR: 2,623. IC: 0.515-13.353. P = 0.246). It was observed more time cervical ripening - delivery in prolonged pregnancies cohort (25.96h vs 20.11h); p < 0.001. Umbilical cord medium pH was significantly superior in ruptured membranes group (7.25 vs 7.23); p = 0.017. No significant differences were observed in the rest of analyzed outcomes. CONCLUSIONS: Pregnancies electively ended for premature rupture of membranes are associated with a shorter time to delivery and a slightly superior umbilical cord pH than induced prolonged pregnancies. Neonatal hospitalization requirement is determined by gestational age but not by the rupture of the membranes. Cervical ripening in those patients has been demonstrated to be secure and effective.