[Autoimmune thrombocytopenia and pregnancy]

Idiopathic thrombocytopenic purpura is an auto-immune disease that carries a risk of haemorrhage when the number of platelets drops to lower than 50 X 10(9)/l and particularly when the bleeding time is prolonged. Thrombocytopenic purpura and pregnancy can be associated with one another and the frequency of that is about 1/5000. Maternal mortality and morbidity are, however, practically nil when proper therapeutic measures are taken. Since 1981 IG IV, which is expensive but rapidly effective, is available to overcome corticotherapeutic failures and to avoid splenectomy in acute cases. Since the maternal anti-platelet factor can cross the placenta, the fetus may become thrombocytopenic like the mother and at risk of the complications of haemorrhage and particularly intra-cranial haemorrhage during delivery vaginally. Screening for fetuses that are affected (52% of the cases) is now possible, not by relying on the maternal platelet count, which is without any prognostic value for the fetus, nor on the levels of anti-platelet antibodies but on the use of examining fetal scalp capillary blood at the onset of labour. This test may make it possible to carry out a vaginal delivery safely when the fetal platelet count is higher than 50 X 10(9)l, whereas if it is lower than this figure a prophylactic caesarean operation should be carried out. There is much promise in the possibility of sampling blood in the fetal cord using ultrasound techniques. In a small number of cases that has already made it possible to diagnose the condition of thrombocytopenia in the fetus even before labour has started. It may in the future even make it possible to carry out treatment of the fetus in utero followed by a normal delivery, whether the treatment is carried out by treating the mother or directing platelets or better still IG IV directly into the fetal circulation.