What types of uterine anomalies, if any, cause more pregnancy complications, compared to the other anomalies? An evaluation of a large population database.

Objective: to compare pregnancy risks between different congenital uterine anomalies utilizing other congenital anomalies as a control group in a large population database. Design, setting, and sample: A retrospective population-based cohort study from the Healthcare-Cost-Utilization Project-Nationwide-Inpatient-Sample(HCUP-NIS) included-3,846,342 births(2010-2014). Of them 6195 deliveries were to women with bicornuate uteri, 798 with arcuate uteri, 2255 with didelphys uteri, 802 with unicornuate uteri and 1404 with septate uteri. Main Outcome Measures and Results: After adjustent for confounders, women with bicornuate uteri were more likely to deliver vaginally(aOR 1.4, 95%CI: 1.1-1.9), P=0.01), less likely to deliver by cesarean(CD) and had lower risk of SGA(aOR 0.8, 95%CI: 0.7-0.9, P=0.03) when compared to the other anomalies (aOR 0.6, 95%CI: 0.5-0.6), P=0.0001). Pregnant women with arcuate uterus had lower risks of preterm delivery((aOR 0.6, 95%CI: 0.5-0.8), P=0.0001), less chance of operative vaginal delivery(aOR 0.5, 95%CI: 0.2-0.9), P=0.04), and higher risk for CD(aOR 1.6, 95%CI: 1.4-2, P=0.0001). Pregnant women with didelphys uteri had higher risk of PPROM(aOR 1.6, 95%CI: 1.3-1.9), P=0.0001), preterm delivery(aOR 1.5, 95%CI: 1.3-1.6), P=0.0001), CD(aOR 1.4, 95%CI: 1.2-1.5, P=0.0001) and wound complications (aOR 1.6, 95%CI: 1.1-2.4), P=0.02). Pregnant unicornuate uteri had increased risks of preterm delivery(aOR 1.4, 95%CI: 1.1-1.6), P=0.0001), CD(aOR 2, 95%CI: 1.6-2.5), P=0.0001) and of SGA(aOR 1.8, 95%CI: 1.4-2.3, P=0.0001). Pregnant septate uteri had higher risk of chorioamnionitis(aOR 1.5, 95%CI: 1.1-2.1), P=0.048) and CD(aOR 1.4, 95%CI: 1.2-1.6), P=0.0001). Conclusion: We demonstrated that there are different risks for certain adverse pregnancy and neonatal outcomes in diverse uterine anomalies as compared to the other anomalies