Sirenomelia: A Case Report

Abstract

Sirenomelia or Mermaid syndrome is a rare congenital malformation characterised by fused lower limbs, genitourinary abnormalities, imperforate anus and a single umbilical artery. Its incidence is about 1:1,00,000 births. This is a case of sirenomelia which was detected in a fetus of about 35 wks. The fetus was delivered by emergency Caesarean section with poor Apgar score and died soon after birth. The fetus had fused lower limbs, a single foot and four digits. The urinary system and adrenal glands were absent. The gonads couldn't be detected. The terminal part of the colon was blind-ending and distended with meconium. The abdominal aorta below the umbilical artery was rudimentary and gave off two iliac arteries. The right iliac artery continued into the thigh. The left iliac artery was small. There was right pulmonary aplasia and left pulmonary hypoplasia. Radiograph of the fetus revealed partially fused femurs, separate tibiae, but no fibulae. There were only 3 metatarsals, each of them having a single phalanx. Sirenomelia cases usually die because of pulmonary hypoplasia, aplasia or renal agenesis. Though there are a few theories regarding aetiopathogenesis, there is still no such one which can fully explain all the features. The sirenomelia cases can be detected by ultrasound antenatally. Such babies cause difficult labor and are usually delivered by Caesarean section but death usually occurs soon after birth. Once the diagnosis is made during early pregnancy, termination of pregnancy is advisable.