Neonatal alloimmune thrombocytopenia with HLA alloimmunization: case report with immunohematologic and placental findings.

Severe neonatal thrombocytopenia is associated with a significant risk of neonatal bleeding complications. It may result from increased consumption, increased destruction, deficient production, or abnormal sequestration within the spleen. When immune mediated, most cases of clinically significant neonatal thrombocytopenia are due to maternal alloimmunization to paternally derived platelet antigens present on fetal platelets.