[Dissociation of maternal and fetal platelet levels in maternal idiopathic thrombocytopenic purpura. Diagnosis of fetal thrombocytopenia by cord ultrasound-guided puncture].

Severe foetal thrombocytopenia (24,000 platelets per cubic mm) was diagnosed in a 37-week pregnant woman. The primigravida, primipara mother had been affected with idiopathic thrombocytopenic purpura at the age of 6 years, in remission since the age of 8 years (after splenectomy). The prenatal diagnosis was made by foetal blood sampling performed when the mother's platelet count was normal. The expected haemorrhagic complications of vaginal delivery were avoided by a caesarean section.