7 Immune thrombocytopenic purpura in pregnancy

Of all pregnant women 1.2% have platelet counts below 100×10⁹/l. Only a small proportion of these have immune thrombocytopenic purpura (ITP). ITP is caused by antibodies directed against one's own platelets and may affect the mother as well as the fetus. No cases with documented intrauterine fetal bleeding have been reported. The most critical time for the fetus is usually a few days after birth. Hitherto the patient's history has been the best predictor of maternal and neonatal complications. Diagnostic cordocentesis entails a considerable risk and is to be discouraged in most situations. Intrauterine transfusions are effective only for a very limited period. There is no evidence that caesarean section protects the thrombocytopenic infant from intracranial haemorrhage. We therefore recommend restricting caesarean section to obstetric indications and to situations with proven fetal thrombocytopenia and enhanced obstetric risk. The safe cut-off level has yet to be ascertained. It is mandatory to control the newborn's platelet count during the first three days of life.