Antiplatelet antibodies and platelet counts in pregnancies complicated by autoimmune thrombocytopenic purpura.

In 48 pregnant women with autoimmune thrombocytopenic purpura, no consistent correlation was found between the infant platelet count and either the maternal platelet count, a previous maternal splenectomy, or maternal treatment with corticosteroids. Although the concentration of antiplatelet antibody in maternal serum frequently reflected the severity of neonatal thrombocytopenia, a number of exceptions to this observation limited the clinical usefulness of the test for individual patients. Antiplatelet antibody levels in the amniotic fluid were always low. A twin gestation in this series of patients in which one infant was thrombocytopenic and the other was not also showed that no antepartum maternal clinical characteristic or laboratory test can accurately predict the fetal platelet count. Only fetal platelet counts from scalp samples obtained prior to or early in labor from 25 patients with autoimmune thrombocytopenic purpura proved to be reliable in assessing the degree of fetal thrombocytopenia and selecting the appropriate route of delivery.