[Abdominal vascular malformations and Down syndrome].

Malformations of the abdominal venous system are rare vascular disorders. These entities are associated with other malformations and with chromosomal anomalies such as trisomy 21. Abdominal venous malformations are probably the most frequent congenital vascular malformations in Down syndrome. Prenatal diagnosis allows the early follow-up and treatment of complications. We present a case of Down syndrome associated with an abdominal venous malformation diagnosed at the first trimester of pregnancy.