Sirenomelia.

Sirenomelia is a rare congenital anomaly with incidence of 1.5-4.2 per 100,000 births. Vascular steal phenomenon, posterior axial mesodermal defect or teratogenic defects have been implied in its pathogenesis. The authors present two cases with associated upper limb involvement and vertebral defects and complete absence of one lower limb bones in one case. Autopsy revealed abnormalities in internal organs. Both cases were associated with single umbilical artery and severe oligohyramnios. Sirenomelia should be suspected in antenatal period in cases presenting with severe oligohydramnios and intrauterine growth retardation for a early diagnosis and appropriate management of pregnancy.