Obstetric outcomes of women with congenital uterine anomalies in the United States.

ABSTRACT

BACKGROUND: Due to the rarity, congenital uterine anomaly type-specific evaluation of pregnant women has been relatively understudied. OBJECTIVE: To describe national-level obstetric outcomes in women with congenital uterine anomalies. STUDY DESIGN: This cross-sectional study queried the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample. Pregnant women with diagnosis of congenital uterine anomalies who had hospital delivery between 2016 and 2019 were examined. The World Health Organization's International Classification of Disease, 10th revision coding was used to delineate type of congenital uterine anomaly, diagnoses, and procedures performed during the index admission. Primary outcomes included pregnancy outcome, which was classified as full-term live birth, preterm live birth, abortion/stillbirth, or ectopic pregnancy. Secondary outcomes included obstetric comorbidities and severe maternal mortality, which were compared between different subtypes of congenital uterine anomalies with multivariable logistic regression model. RESULTS: A total of 50,180 pregnant women with congenital uterine anomalies were identified. Bicornuate was the most common subtype (73.5%), followed by arcuate (13.5%) and unicornuate (10.0%). 70.6% of women with congenital uterine anomalies had a full-term live birth, 26.8% had a preterm live birth, 2.1% had an abortion or stillbirth, and 0.4% had an ectopic pregnancy. 61.8% of preterm births occurred between 33 and 36 weeks, 16.9% between 30 and 32 weeks, and 21.3% at <30 weeks. There were 1,440 (2.9%) periviable births. The preterm (34.5%) and periviable (6.9%) birth rates were highest in the uterine didelphys group. Overall, two-thirds (65.7%) of patients with congenital uterine anomalies were delivered via cesarean section. When compared to arcuate uterus, risk of severe maternal morbidity in septate uterus (4.8% vs 2.6%, adjusted-odds ratio [aOR] 2.60, 95% confidence interval [CI] 1.49-4.52) was increased, including hemorrhage (14.5% vs 7.7%, aOR 2.16, 95% CI 1.51-3.07). This was followed by uterine didelphys (4.2% vs 2.6%, aOR 1.75, 95% CI 1.24-2.47), unicornuate uterus (3.8% vs 2.6%, aOR 1.61, 95% CI 1.29-2.01), and bicornuate uterus (3.0% vs 2.6%, aOR 1.23, 95% CI 1.04-1.47). CONCLUSION: While the majority of patients with congenital uterine anomalies result in full-term viable deliveries, each subtype of congenital uterine anomalies confers different obstetric risks. Uterine didelphys was associated with the highest risk of preterm birth, while septate uterus was associated with the highest risk of severe maternal morbidity. While this hospital delivery dataset likely overrepresents bicornuate uteri, this populational data may help inform patients with congenital anomalies considering pregnancy.