Congenital uterine anomalies and adverse pregnancy outcomes.

OBJECTIVE We sought to estimate whether the presence of a maternal uterine anomaly is associated with adverse pregnancy outcomes. STUDY DESIGN This retrospective cohort study included singleton pregnancies undergoing routine anatomic survey from 1990 through 2008 at a major tertiary care medical center. Pregnancies with a diagnosis of uterine anomaly (uterine septum, unicornuate uterus, bicornuate uterus, uterine didelphys) were compared to those with normal anatomy. Primary outcomes of interest were spontaneous preterm birth (PTB), breech presentation, and cesarean delivery. RESULTS The presence of an anomaly was associated with PTB <34 weeks (adjusted odds ratio [aOR], 7.4; 95% confidence interval [CI], 4.8-11.4; P < .01), PTB <37 weeks (aOR, 5.9, 95% CI, 4.3-8.1; P < .01), primary nonbreech cesarean delivery (aOR, 2.6; 95% CI, 1.7-4.0; P < .01), preterm premature rupture of membranes (aOR, 3.2; 95% CI, 1.8-5.6; P < .01), and breech presentation (aOR, 8.6; 95% CI, 6.2-12.0; P < .01). CONCLUSION Women with a uterine anomaly are at risk for PTB, highlighting an at-risk population that needs additional study for possible interventions for PTB prevention.