Prenatal diagnosis of hemophilia by fetal blood sampling under ultrasound guidance.

In utero fetal blood sampling was performed in 55 cases for prenatal diagnosis of hemophilia A and B. Fifteen fetuses were found to be affected. However, with this new procedure, it was possible to demonstrate that fetuses were not hemophiliacs in 40 cases. Therefore, pregnancy was not interrupted; these infants were born and definitely proven to be normal. There were no diagnostic errors.