ABSTRACT
Alloimmune thrombocytopenia (AIT) is a syndrome that develops as a result of maternal sensitization to fetal platelet antigens. The antibodies are then transported across the placenta to the fetal circulation where they result in the destruction of the fetal platelets. Platelets possess specific alloantigens that are expressed on the surface membrane glycoproteins. The hematocrit may be decreased if significant bleeding has occurred. A definitive diagnosis can be made by phenotyping parental platelets and demonstrating antiplatelet antibodies in the maternal serum, which are specific for the antigen incompatibility identified. Serial platelet transfusions are efficacious, but necessitate weekly invasive procedures with the additive risks of pregnancy loss. Medical management with maternally administered intravenous gamma globulin appears to be effective in the majority of, but not all, cases.
