Abstract
Objective To compare the relative contribution of premature rupture of membranes (PROM) to
preterm births in singleton compared with multifetal gestations.
Study Design A population-based retrospective cohort study of 291,782 nonanomalous live births
in the state of Ohio from January 1, 2006, to December 31, 2007, identified through
birth certificate data. Frequency of PROM was compared between singleton and multifetal
gestations and then stratified by gestational age at birth. Multivariate regression
analysis estimated the risk of PROM by plurality in each gestational age group, accounting
for influential risk factors.
Results The frequency of PROM increased with increasing plurality of gestation. The relative
proportion of preterm birth <37 weeks complicated by PROM increased with gestational
plurality 13.2% singletons, 16.8% twins, 20.0% triplets, 19.6% quadruplets, and 100%
for higher-order multiples (p < 0.001). The frequency of PROM increased with earlier gestational age at birth,
regardless of plurality. The increased risk of PROM in multifetal gestation persisted
even after adjustment for influential concomitant risk factors.
Conclusion The proportion of preterm birth attributable to PROM increases by plurality of gestation,
with its most significant contribution in higher-order multiples and at earliest gestational
ages when outcomes are the poorest.
Keywords
PROM - preterm/premature birth - multifetal gestation - preterm rupture of membranes
- preterm labor
