NAIT is the commonest cause of a very low platelet count, and the commonest cause of intracranial haemorrhage in the term neonate.In case of severe thrombocytopenia, the neonates may exhibit bleeding complications at or a few hours after delivery. The most serious complication is intracranial hemorrhage, leading to death in approximately 10% of symptomatic babies or neurologic sequelae in 20% of cases. 80% of intracranial hemorrhages occur before birth. After birth the greatest risk of bleeding is in the first four days of life. Related conditions
Immune thrombocytopenic purpura (ITP), sometimes called idiopathic thrombocytopenic purpura is a condition in which autoantibodies are directed against a patients own platelets, causing platelet destruction and thrombocytopenia. Anti-platelet autoantibodies in a pregnant woman with immune thrombocytopenic purpura will attack the patients own platelets and will also cross the placenta and react against fetal platelets. Therefore, ITP is a significant cause of fetal and neonatal immune thrombocytopenia. Approximately 10% of newborns affected by ITP will have platelet counts <50,000 μL−1 and 1% to 2% will have a risk of intracerebral hemorrhage comparable to infants with NAIT.Mothers with thrombocytopenia or a previous diagnosis of ITP should be tested for serum anti-platelet antibodies. A woman with symptomatic thrombocytopenia and an identifiable anti-platelet antibody should be started on therapy for their ITP which may include steroids or IVIG. Fetal blood analysis to determine the platelet count is not generally performed as ITP-induced thrombocytopenia in the fetus is generally less severe than NAIT. Platelet transfusions may be performed in newborns, depending on the degree of thrombocytopenia.
However, IVIG and platelet transfusions are also associated with harm and therefore should be avoided if they are not necessary.After a first affected pregnancy, if a mother has plans for a subsequent pregnancy, then the mother and father should be typed for platelet antigens and the mother screened for alloantibodies. Testing is available through reference laboratories (such as ARUP). DNA testing of the father can be used to determine zygosity of the involved antigen and therefore risk to future pregnancies (if homozygous for the antigen, all subsequent pregnancies will be affected, if heterozygous, there is an approximate 50% risk to each subsequent pregnancy). During subsequent pregnancies, the genotype of the fetus can also be determined using amniotic fluid analysis or maternal blood as early as 18 weeks gestation to definitively determine the risk to the fetus. References
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