Congenital uterine anomalies and associated pregnancies: findings and pitfalls of sonographic diagnosis.

Fifteen pregnancies occurring in 13 patients with congenital uterine anomalies were analyzed. The anomalies included bicornuate uteri (nine cases), subseptate uteri (two), septated uteri (one), and uterus didelphys (one). Identification of a bilobed uterine contour with an anterior and/or posterior indentation, an eccentrically located gestational sac, and echogenic endometrial debris in the nongravid horn, reliably indicated a coexistent uterine anomaly. Uterine anomalies became difficult or impossible to identify with increasing gestational age. Entities potentially confused with uterine anomalies include cornual leiomyomata, ectopic gestation, placental septations, and uterine scarring. Awareness of the sonographic findings of pregnancies in anomalous uteri should improve their detection and may alter obstetrical management.