Antenatal ultrasonographic appearance of a cloacal anomaly

Background: Cloacal anomalies are rare abnormalities with highly variable f orms, which makes them difficult to diagnose antenatally. We present a cloa cal anomaly case with interesting antenatal ultrasonographic findings. Case: A 24-year-old woman, gravida 1, para 0, presented at 23 weeks' gestat ion with ultrasonographic evidence of fetal ascites. Between 23 and 30 week s' gestation, serial ultrasounds showed changing features of a cloacal anom aly, consisting of fetal ascites, a cystic pelvic mass, hydronephrosis, and oligohydramnios. Conclusion: Serial antenatal ultrasound helped diagnose changing features o f a cloacal anomaly in our case, thus allowing directed antenatal counselin g and appropriate perinatal treatment. (Obstet Gynecol 2000;95:1013-5. (C) 2000 by The American College of Obstetricians and Gynecologists.).