[Hydrops and common atrioventricular canal in a fetus of karyotype 47(XY)+21. Ultrasonic diagnosis at twenty weeks].

The Authors report a case of fetal ascites and hydrothorax with common atrioventricular canal diagnosed by ultrasound. They suspect a Down's syndrome confirmed by amniocentesis for fetal caryotype. They attach importance to the early diagnosis and to the cytogenetic research for therapeutic trend.