Neonatal alloimmune thrombocytopenia

Abstract

Neonatal alloimmune thrombocytopenia occurs in one in 1,000-1,500 live births and is the most common cause of severe thrombocytopenia and intracranial hemorrhage in term infants. It is the equivalent of red blood cell alloimmunization and is due to transplacental passage of maternal antibodies against paternally derived fetal platelet antigens. A diagnosis of neonatal alloimmune thrombocytopenia should be considered for any neonate with unexplained thrombocytopenia. Once the diagnosis is made, it is known that all subsequent pregnancies are at risk for severe disease. In order to prevent the devastating and potentially life-threatening mani- festations of the disease, the goal is to initiate treatment early with serial percutaneous umbilical blood sampling, intravenous immunoglobulin administration, prednisone, and/or fetal platelet transfusions. Timing of delivery is variable with delivery for severe disease recommended at an earlier gestational age. Vaginal delivery can be considered if the fetal platelet count is greater than 50,000-100,000 µL. Thrombocytopenia due to neonatal alloimmune thrombocytopenia usually resolves spontaneously within 1-2 weeks after delivery, but a platelet transfusion may be necessary to prevent a serious hemorrhagic event. In all cases, a multidisciplinary approach to care should be undertaken with delivery at a tertiary care center.