A classification of congenital uterine anomalies predicting pregnancy outcomes.

Objective: To evaluate pregnancy outcomes in women with uterine anomalies by applying a method for diagnosing and classifying congenital uterine malformations.

Design: Retrospective study.

Setting: Tertiary care center.

Population: Ninety-four women with uterine anomalies who delivered after 22 gestational weeks.

Methods: Excluding the 14 women with a history of surgery and seven with one endometrial cavity, 73 women with two endometrial cavities were subdivided into those with two external uterine orifices (2-OS subgroup) and those with one external uterine orifice (1-OS subgroup).

Main Outcome Measures: Pregnancy outcomes, such as preterm birth, abnormal fetal presentation, cesarean delivery and placental abruption.

Results: The 2-OS subgroup comprised women with a didelphic or complete septate uterus who had a significantly higher rate of cesarean delivery (91% vs. 18%, p < 0.001) than the control group (normal uterine morphology; n = 5763). The 1-OS subgroup comprised women with a bicornuate or incomplete septate uterus who had significantly higher rates of preterm birth (27% vs. 5%, p < 0.001) and placental abruption (14% vs. 0.7%, p < 0.001) than the control group.

Conclusions: Classification of uterine anomalies by the number of uterine endometrial cavities and external uterine orifices is an easy and reliable means of predicting pregnancy outcomes.