Rupture of the fetal membranes prior to the onset of labor is a common event. With its occurrence, the risk is increased for serious maternal and fetal infections, dysfunctional labor, and the need for operative delivery. Fortunately, for most women with prelabor rupture of membranes (PROM) at term, labor begins spontaneously in the hours following membrane rupture. If spontaneous labor does not commence shortly after PROM at term, and the patient's cervix is favorable, labor induction should be initiated. Women with uncomplicated gestations who have an unfavorable cervical score may be managed expectantly, undergo immediate labor induction, or be observed for an arbitrary time period and then undergo labor induction. Recent clinical trials have shown that immediate labor induction for women with PROM at term and an unfavorable cervical score is preferable in the context of maternal and neonatal outcome, cost-effectiveness, and patient satisfaction.
Introduction
Prelabor or premature rupture of membranes (PROM) is defined as the spontaneous leakage of amniotic fluid prior to the onset of labor. This definition is subcategorized into preterm PROM (when the gestational age is less than 37 weeks) and term PROM (when the gestational age is 37 weeks or greater). This diagnosis excludes women who have rupture of the fetal membranes (amniorrhexis) following the onset of regular uterine contractions consistent with spontaneous labor. PROM occurs in approximately 15% of pregnancies, and, of these, approximately 90% occur in term parturients.[1,2]
A number of risk factors have been associated with preterm PROM, the majority of which have in common the involvement of either the presence of intrinsically weakened membranes or the acquisition of inflammatory mediators resulting in weakening of the membranes.[1,3,4] However, in women with PROM at term, these risk factors are usually absent, and amniorrhexis occurs without premonitory signs or symptoms.[5] There is a circadian distribution in the onset of PROM, with peak incidence occurring between 2:00 and 4:00 am.[6] A full discussion of preterm PROM is beyond the scope of this article, but guidelines are provided for the management of PROM at term.