[Sirenomelia--prenatal diagnosis and clinical consequences of a rare abnormality].

Sirenomelia or the mermaid syndrome is a rare birth defect, often combined with severe malformations of the urogenital system and the lower gastrointestinal tract. The incidence is about one case in 60,000. Ultrasound can be very important in early detection of this deformity. Because of the high incidence of oligohydramnios amnioninfusion could be helpful. Also a magnetic resonance radiographia in the prenatal period could be performed. We report three cases of sirenomelia and in addition the literature is reviewed and discussed.