The association between congenital uterine anomalies and perinatal outcomes–does type of defect matters?

Objective: To evaluate the association between congenital uterine anomalies (CUA) and adverse perinatal outcomes stratified by type of anomaly. Methods: A retrospective cohort study of all women delivered in one university-affiliated medical center between 2010 and 2017 with CUA. Multiple pregnancies and pregnancies complicated by fetal anomalies were excluded. Maternal and short-term neonatal outcomes were evaluated and compared between women with unification defects (unicornuate, bicornuate, or uterus didelphys), and canalization defects represented by septate uterus. Univariate analysis was utilized followed by multivariate analysis to adjust for confounders. p <.05 was considered significant. Results: Among 167 pregnancies with CUA, 92 (55.1%) had bicornuate uterus, 32 (19.1%) septate uterus, 26 (15.6%) didelphys uterus, and 17 (10.1%) unicornuate uterus. Maternal demographics and obstetric characteristics were similar between women with unification and canalization defects. The entire cohort had high rates of preterm delivery (PTD), malpresentation, and cesarean delivery (CD) (25.7%, 42.5%, and 63.5%, respectively). In comparison to unification defects, pregnancies in women with canalization defects (septate uterus), had increased risk for PTD <32 weeks (12.5% vs. 2.9%, p =.02), and placental abruption (12.5% vs. 3%, p =.02), however, a lower overall rate of CD (46.9% vs. 67.4%, p =.03). Following adjustment to confounders (age, BMI, nulliparity, chronic hypertension, and smoking) none of the results remained statistically significant. There were no differences in neonatal outcomes between the groups. Conclusions: Overall, women with CUA have a high prevalence of adverse pregnancy outcomes. However, outcome does not differ by type of anomaly.