First Trimester Diagnosis of Sirenomelia: A Case Report

Sirenomelia or the mermaid syndrome is a rare and lethal congenital anomaly. It is characterized by fusion of lower extremities. It is associated with bilateral renal agenesis, anomalies of rectum, sacrum, cardiovascular system and abdominal wall. Pathognomic finding is a single umbilical artery, the persistent vitelline artery' which distinguishes sirenomelia from caudal regression syndrome. Sirenomelia has strong association with maternal diabetes mellitus. We report a case of sirenomelia diagnosed in first trimester. Early diagnosis was possible as protocol-based anatomic evaluation was performed. Diagnosis of sirenomelia is easier in first trimester as severe oligohydramnios in later gestation hampers the fetal evaluation.