Arcuate Uterus as an Independent Risk Factor for Adverse Pregnancy Outcomes [17B

Abstract

INTRODUCTION: Mullerian anomalies are associated with adverse pregnancy outcomes. However, it is unclear if arcuate uterus, a milder abnormality, is also associated with adverse outcomes. The objective of our study is to estimate the association between arcuate uterus and adverse pregnancy outcomes using a similarly high risk control cohort. METHODS: Retrospective cohort study of women with an arcuate uterus cared for by a single maternal-fetal medicine practice from 2005 to 2018. We included all women with a singleton pregnancy and an arcuate uterus and randomly selected (3:1) patients with singleton pregnancies and no uterine anomalies from the same practice as controls. Baseline characteristics and pregnancy outcomes were compared. Chi-square test, Fisher's exact test, and Student's t-test were used, as appropriate. IRB approval was obtained. RESULTS: A total of 32 women with an arcuate uterus and 96 controls were included. There were no differences in baseline characteristics between the groups. Women with arcuate uterus had lower birthweights (2992+/-600 vs. 3238+/-560 g, p=0.037) and a higher likelihood of IUGR (25.0% vs. 9.4%, p=0.024), despite similar starting BMI and weight gain in pregnancy. There was a higher rate of malpresentation (21.9% vs. 5.2%, p=0.005), but not an overall increased risk of cesarean delivery. CONCLUSION: Having an arcuate uterus is significantly associated with lower birthweight and IUGR, as compared to high-risk controls. This suggests that arcuate uterus is itself a risk factor for poor fetal growth, as opposed to simply being a marker for a higher risk pregnancy.