Platelet disorders in pregnancy: implications for mother and fetus

Platelet disorders in pregnancy are not uncommon. Most often, obstetricians are faced with a patient with undiagnosed thrombocytopenia and have the responsibility of deciding if the condition is ITP, gestational thrombocytopenia, or a process related to pre-eclampsia. Correct diagnosis is important because ITP can be associated with fetal thrombocytopenia, making route of delivery important. In alloimmune thrombocytopenia, the mother develops antibodies to a specific platelet antigen present on the fetal platelet but absent on her own. Severe AIT can cause intracranial hemorrhage and have disastrous consequences for the fetus and neonate. In preliminary studies antenatal intravenous gamma globulin therapy has shown promise in preventing the development of intracranial hemorrhage and ameliorating fetal thrombocytopenia. Essential thrombocythemia with a platelet count of greater than 600 x 10(9) platelet/L can occur in pregnancy; therapy consists of antiplatelet aggregating agents such as aspirin, and plateletpheresis. Platelet function disorders can be acquired or inherited. Acquired platelet dysfunction disorders are usually caused by drugs such as aspirin or indomethacin, or by a systemic disease. Hereditary disorders of platelet function can be diagnosed in utero, but cordocentesis may represent an unacceptably high risk. For prenatal diagnosis, other methods, such as chorionic villus sampling or amniocentesis, should be investigated as an alternative to the potentially high risk of cordocentesis.