861 Racial and ethnic differences in contribution of premature rupture of membranes to preterm birth

Abstract

Premature rupture of membranes (PROM) is a major driver of both indicated and spontaneous preterm birth. We sought to compare the contribution of PROM to preterm birth across gestational age and racial/ethnic groups. We performed a retrospective cohort study utilizing a population-based database of all live births in Ohio from 2006 to 2015 from birth certificate data. Analyses were limited to preterm cases and categorized as previable (14w0d through 19w6d), periviable (20w0d through 25w6d), extreme preterm (26w0d through 28w6d), early preterm (29w0d through 33w6d), and late preterm (34w0d through 36w6d). PROM is recorded on the birth certificate as Premature Rupture of the Membranes (prolonged, >12 hours). Rates of PROM were compared among gestational age categories and stratified by race and ethnicity as recorded on the U.S. certificate of live birth. Over the ten-year study period, there were 1,423,709 live births in Ohio, corrected for multifetal gestations. There were 137,084 preterm births, with PROM occurring in 25,096 (18.3%) of the preterm deliveries. The rate of PROM decreased significantly with increasing gestational age, from 33.0% in previable births to 14.4% in late preterm births (see Figure; p < 0.001). The contribution of PROM to preterm birth was similar between racial and ethnic groups, with only minimal differences noted at later preterm gestational ages. The relative contribution of PROM to preterm birth was higher at the earliest gestational ages (previable and periviable births), when compared to late preterm births, even after adjustment for confounding risk factors. PROM contributes more to preterm birth at earlier gestational ages but does not differ significantly by maternal race and ethnicity. Rates of PROM are especially high in previable and periviable deliveries, accounting for nearly one third of births in these categories. Efforts to reduce preterm birth will require addressing the pathologic mechanisms that lead to PROM.View Large Image Figure ViewerDownload Hi-res image Download (PPT)