[Fetal and neonatal alloimmune thrombocytopenias].

Fetal and neonatal alloimmune thrombocytopenias result from maternal immunization against fetal specific platelet antigens inherited from the father that the mother lacks. The incidence has been estimated to one in 800 to one in 1000 live births. The most feared complication in case of severe thrombocytopenia is the occurrence of intracranial hemorrhage, leading to death or neurological sequelea. The diagnosis is straightforward when a maternal alloantibody is detected and the offending antigen identified in the infant. Any difficulties in confirming the diagnosis should not delay the treatment. Since the first description of these conditions in the 1950's, significant progress has been made in laboratory diagnosis and management.