ABSTRACT
Spontaneous rupture of the fetal membranes is a normal component of labor and delivery, and most often occurs during the active phase. In contrast, rupture of the membranes before the onset of labor at any stage of gestation is designated prelabor rupture of the membranes (PROM). If this occurs at a gestational age of less than 37 weeks, the event is characterized as preterm prelabor rupture of the membranes. Prelabor rupture of the membranes occurs in approximately 2.0-3.5% of all pregnancies and is associated with 30-40% of preterm deliveries1. As such, it is the leading identifiable cause of preterm delivery and its complications, including respiratory distress syndrome, neonatal infection and intraventricular hemorrhage2. Preterm PROM occurring very early in pregnancy carries a high risk of perinatal morbidity and mortality, primarily as a result of prematurity as well as acute complications such as infection, cord prolapse and abruption. According to the risk assessment study of Ross and co-workers, both multiple gestation and preterm premature rupture of the membranes are independently associated with at least a four-fold risk of neonatal intensive-care unit admission. Notably, triplet or greater gestation and preterm PROM carried the highest odds ratios (17 and 15, respectively)3. The risk of these complications increases with decreasing gestational age at membrane rupture. Mercer4 suggested differentiating preterm pretern ROM into three broad categories according to clinical relevance: ‘previable PROM’, which occurs before the limit of viability (less than 23 weeks); ‘preterm PROM remote from term’ (from viability to about 32 weeks’ gestation); and, finally, ‘preterm PROM near term’ (approximately 32-36 weeks’ gestation).
