Sirenomelia sequence: Early prenatal diagnosis of one rare case associated with acardiac malformation

Sirenomelia sequence is a very rare congenital malformation, with incidence of around 1.5-4.2 per 100,000 births. Prenatal diagnosis of sirenomelia in the first trimester is rare; there are only five cases reported for the present, and the association of sirenomelia with acardiac malformation is even rarer. We present a rare case of sirenomelia associated with acardiac malformation detected in the first trimester through combined two-dimensional, three-dimensional and color Doppler sonographies. © 2006 Springer-Verlag.