New insights in fetal and neonatal alloimmune thrombocytopenia

Abstract

During the recent years considerable advances in the clinical and laboratory diagnosis of alloimmune thrombocytopenia have been done. Feto‐maternal alloimmunization is the commonest cause of severe isolated fetal and neonatal thrombocytopenia. The condition results from maternal immunization against specific fetal platelet antigens (HPA). Unlike the haemolytic disease of the fetus and newborn the first newborn was found to be affected. The diagnosis is usually made at birth when an otherwise ‘well’ term infant exhibits bleeding at delivery or few hours afterwards. The most feared complication of this disorder is the occurrence of intracranial haemorrhage (ICH) as a result of severe thrombocytopenia leading to death or neurological sequelae. The diagnosis of alloimmune thrombocytopenia enables appropriate management of the index case and future pregnancies. The diagnosis is confirmed by laboratory testing with the identification of the maternal alloantibody and the offending antigen present in the fetus or neonate that is absent in the mother. In a recent retrospective study concerning 75 HPA‐1b1b women, we have shown that the diagnosis of maternal alloimmunization was mostly established at delivery and the women were primigravida in 51% of the cases. The deleterious consequence of this severity was evidenced by in utero or postnatal ICH. Subsequent pregnancies were managed according to three different protocols, steroids only, intravenous immunoglobulin (IVIG) or IVIG and steroids. We found that the most efficacious antenatal therapy for fetal alloimmune thrombocytopenia is maternal treatment with IVIG and steroids. In summary, this study shows (1) that the morbidity linked with this condition is important to be considered for further antenatal screening (2) that antenatal management in referral centers should be suggested to high‐risk pregnant women.