Sirenomelia: the Mermaid Syndrome

Sirenomelia (the Mermaid Syndrome) is a rare and lethal congenital anomaly with an incidence of one in 100,000 of normal pregnancies. It is an extremely rare set of birth defects, which can vary in expression. The condition gets its name from one of the defects present, which is a fusing of the legs. The fused nature of the legs has been compared to a mermaid in appearance, hence the name. The characteristic features of Sirenomelia are complete fusion of the lower limbs, commonly associated with renal agenesis, absent external genitalia and other gastrointestinal defects. Another pathognomonic finding is the presence of single umbilical, persistent vitelline artery which is the chief distinguishing anatomic finding from Caudal Regression Syndrome. The termination of pregnancy is the choice of management as the case is diagnosed on the antenatal ultrasound which can show the features like renal agenesis with no liquor, fusion of the lower limbs. In our case report, the baby was delivered through Normal Vaginal Delivery with characteristic features of Sirenomelia on examination. The baby expired 8 hours after delivery.