[Severe form of neonatal hemolytic disease by anti-Vel allo-immunization].

Background: Routine detection of maternal sensitization during pregnancy sometimes reveals alloimmunization by exceptional antigens.

Case Report: A first pregnancy was complicated by a severe post-partum anemia in the mother, that required a blood transfusion. Irregular agglutinins were detected during the first trimester of a second pregnancy, for which the father was different from the first.