Retroverted Uterus in the First Trimester and Associated Pregnancy Outcomes.

Abstract

Objective:  This study aimed to investigate if retroverted (RV) uterus noted on nuchal translucency (NT) ultrasound is associated with second-trimester pregnancy loss and other adverse pregnancy outcomes.

Study design:  This was a retrospective cohort study of patients with RV uterus documented on NT ultrasound at a single academic medical center from October 2019 to March 2023. Subjects were identified using a query for "retroverted" uterine position within an obstetric ultrasound imaging program. For each RV case, two anteverted (AV) subjects were selected for comparison. Patients with multiple gestation, Mullerian anomalies, or fetal aneuploidy were excluded. Maternal demographics, obstetric, and neonatal outcomes were obtained by chart review. Fisher's exact test and Mann-Whitney test were used for categorical and continuous variables, respectively, with p-value <0.05 denoting significance. Multivariable logistic regression was used to adjust for possible confounding variables.

Results:  Analysis included 249 patients-83 RV and 166 AV. RV patients were more likely to identify as Caucasian (71.1 vs. 49.4%, p = 0.001), have private insurance (80.7 vs. 59.4%, p = 0.001), lower body mass index (25.4 ± 5.1 vs 29.1 ± 7.2, p < 0.001), and conceive by in vitro fertilization (IVF, 11 vs. 3%, p = 0.018). Most RV subjects (98%) had a resolution of retroversion by the second trimester. There was no difference in second-trimester pregnancy loss (0 vs. 1.2%, p = 0.55). After adjusting for race and IVF, RV subjects were four times more likely to have first-trimester vaginal bleeding (16.9 vs. 4.2%, odds ratio = 4.1, p = 0.0056). No other differences in adverse outcomes were observed.

Conclusion:  Persistent RV uterus in the first trimester is associated with increased risk of first-trimester vaginal bleeding. However, rates of pregnancy loss were similar between groups, providing valuable information for patient counseling. Significantly more RV subjects conceived by IVF, highlighting the need for further study in this population.

Key points: · Pregnancy outcomes of patients with retroverted uterus have not been widely studied.. · Significantly more patients with a retroverted uterus conceived by in vitro fertilization.. · Patients with retroverted uterus were four times more likely to have first-trimester bleeding.. · Despite increased rates of vaginal bleeding, there was no increased rate of pregnancy loss..