The management of feto-maternal alloimmune thrombocytopenia: report of three cases.

We report herein three cases of severe fetal thrombocytopenia due to anti-human platelet antigen (HPA)- 1a maternal antibodies. The first and the third cases were diagnosed on the basis of previously affected siblings and treated successfully by maternal intravenous human immunoglobulins and corticosteroids. In the second case an unexpected neonatal thrombocytopenia was found after birth without previously affected siblings and treated subsequently with intravenous immunoglobulins. Our experience supports a switch from an invasive management, including early FBS (fetal blood sampling) and platelet transfusions, to a more cautious approach. Also in severe HPA-1a alloimmunization and in 'high risk' fetuses, prenatal maternal treatment could be performed, without previous FBS, only on the basis of a risk score defined by sibling history and parents' genotypes.