Preconception diagnosis of arcuate uterine morphology by three-dimensional transvaginal ultrasonography and subsequent perinatal outcomes in women undergoing infertility treatment: a prospective cohort study

Abstract Purpose The clinical significance of arcuate uterine morphology, a mild fundal indentation regarded as normal in the ASRM 2021 classification, remains unclear. We examined whether arcuate uterine morphology diagnosed before conception by three-dimensional transvaginal ultrasonography (3D-TVUS) is associated with perinatal outcomes. Methods This prospective cohort study included women who underwent infertility treatment (April 2022 to November 2025) and delivered at our hospital. Uterine morphology was classified on 3D-TVUS using an operational definition based on ASRM 2021 (indentation depth <10 mm and fundal angle ≥90° defined as arcuate uterine morphology). Perinatal outcomes were compared between groups; outcomes that differed significantly were entered together into a multivariable logistic regression model with arcuate uterine morphology as the dependent variable. Exploratory analyses by placental implantation site (fundal vs non-fundal) were performed. Results Of 228 women, 41 (18.0%) had arcuate uterine morphology and 182 (79.8%) had normal uterus. The arcuate uterine morphology group had higher rates of gestational diabetes mellitus (GDM) (21% vs 4.0%), fetal growth restriction (FGR) (20% vs 6.6%), and abnormal umbilical cord insertion (34% vs 14%), each remaining associated with it after mutual adjustment. In exploratory analyses of 183 women with evaluable placental site, FGR (33% vs 5.4%) and abnormal cord insertion (75% vs 14%) were more frequent in arcuate uterine morphology with fundal (n = 49) but not significantly with non-fundal implantation. Conclusions Arcuate uterine morphology identified by preconception 3D-TVUS was associated with GDM, FGR, and abnormal umbilical cord insertion. Predictive value and screening benefit remain to be determined.