Association of congenital uterine anomaly with abnormal placental cord insertion and adverse pregnancy complications: a retrospective cohort study.

Objective: Congenital uterine anomalies during pregnancy increase the risk of pregnancy complications such as miscarriage, preterm delivery, fetal malpresentation, cesarean delivery, and fetal growth restriction. However, few studies have examined uterine anomalies in relation to perinatal complications other than those mentioned above. We investigated the association between pregnancies complicated by congenital uterine anomalies and various perinatal outcomes at our institution.

Methods: This retrospective cohort study was conducted from January 2009 to May 2021. We included cases of uterine anomalies, such as septate, bicornuate, unicornuate, and didelphic uterus. First, the perinatal complications and neonatal outcomes were compared between pregnancies complicated by uterine anomalies and those with normal uteri. Second, we conducted an analysis based on the type of uterine anomalies classified into two groups: the minor anomaly group consisted of anomalies limited to the uterine cavity, such as the septate uterus, whereas the major anomaly group included anomalies affecting the uterine shape, such as bicornuate, unicornuate, and didelphic uterus. We compared the incidence of perinatal complications among the major anomaly, minor anomaly, and normal uterus groups.

Results: During the study period, 45 pregnancies were complicated with uterine anomalies. The minor anomaly group included 11 patients and the major anomaly group included 34 patients. The incidence of fetal malpresentation was significantly higher in the uterine anomaly group than in the normal uterus group (18% vs. 3.7%, p = .04). Furthermore, the frequency of abnormal placental cord insertion was significantly higher in the uterine anomaly group (16% vs. 3.7%, p = .01). Examination based on the type of uterine anomaly revealed significant differences in cervical incompetence, malpresentation, cesarean section, and abnormal placental cord insertion. Cervical incompetence was more likely in patients with minor anomalies. In contrast, fetal malpresentation, cesarean section, and abnormal placental cord insertion were more likely in the major anomaly group.

Conclusions: In addition to the findings reported in previous studies, abnormal placental cord insertion was more frequent in pregnancies complicated by uterine anomalies.