Prenatal diagnosis and management of neonatal alloimmune thrombocytopenia.

Neonatal alloimmune thrombocytopenia (NAIT) is an uncommon (1 in 2,000 livebirths) but serious disorder characterized by marked thrombocytopenia in the fetus and neonate. Platelet destruction is caused by a maternal antibody directed against a fetal platelet antigen inherited from the father and lacking in the mother's platelets. Intracranial hemorrhage (ICH) is the most devastating complication of NAIT, affecting approximately 20% of all proven cases, up to 50% of which occur antenatally. Because close to 100% of subsequent pregnancies will be equally or more severely affected, antenatal management directed at preventing ICH in utero has assumed great clinical importance. In recent years, considerable progress has been made in this regard, and although clinical uncertainties still exist, the natural history of this disease and its response to various antenatal interventions have become reasonably well understood. This review will focus on the diagnosis and current management of NAIT, including controversies surrounding current treatment modalities and future prospects for treatment and prevention.