[Fetal and neonatal immune thrombocytopenias].

Fetal and neonatal immune thrombocytopenias with platelet count less than 150.10(9)/l, result from transplacental passage of maternal platelet-specific antibodies. The main risk of these diseases is severe brain damage or death due to intracranial hemorrhage. Prevention and screening are difficult because of the lack of predicting factors. Only some women are at high risk of fetal thrombocytopenia (HLA DRW 52a HPA-la negative women or women with a previous history of immune thrombocytopenic purpura and having platelet-specific autoantibodies). Antenatal diagnosis and therapy have altered the natural course of fetal alloimmune thrombocytopenia. No prenatal treatment has proved to be effective in autoimmune thrombocytopenia and prenatal diagnosis by fetal blood sampling is controversial. A better knowledge of the pathogenesis of gestational incidental thrombocytopenia in otherwise healthy pregnancies, could define a group at high risk of fetal thrombocytopenia.