The management of alloimmune neonatal thrombocytopenia

Baillieres Best Pract Res Clin Haematol. 2000 Sep;13(3):365-90. doi: 10.1053/beha.2000.0083.


Neonatal alloimmune thrombocytopenia (NAITP), defined as thrombocytopenia (platelet count < 150 x 10(9)/l) due to transplacentally acquired maternal platelet alloantibodies, occurs in approximately 1 per 1200 live births in a Caucasian population. In such a population, the majority (> 75 percent) of cases are due to fetomaternal incompatibility for the platelet specific alloantigen, HPA-1a (P1A1, Zwa). Incompatibility for the HPA-5b (Bra) alloantigen is the next most frequent cause of NAITP in Caucasians; much less common is NAITP due to incompatibility for HLA, blood group ABO or other platelet-specific antigens. In non-Caucasian populations (e.g. Orientals) HPA-1a incompatibility is a rare cause of NAITP and other alloantigens e.g. HPA-4b (Penb, Yuka) are implicated. The greatest clinical challenge relates to the antenatal management of pregnant women alloimmunized to the HPA-1a (P1A1, Zwa) antigen, and particularly the subset of such women who have a history of a previously affected infant with severe thrombocytopenia and/or intracranial hemorrhage (ICH). The risk of antenatal ICH in the fetus of such women is high enough to merit intervention, either weekly infusion of high-dose intravenous immunoglobulin G (IVIG) with or without corticosteroids given to the mother (the preferred approach in North American centres), or repeated in-utero fetal platelet transfusions (the preferred treatment approach in some European centres). Post-natal management of severely affected infants centres on the rapid provision of compatible antigen-negative platelets harvested from the mother or a phenotyped donor. The value of antenatal screening programs to detect 'at risk' alloimmunized women during pregnancy continues to be debated.

Publication types

  • Review

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use
  • Antigens, Human Platelet / immunology
  • Blood Platelets / immunology
  • Female
  • Humans
  • Immunoglobulins, Intravenous / therapeutic use
  • Infant, Newborn
  • Isoantibodies / immunology*
  • Isoantigens / immunology
  • Maternal-Fetal Exchange
  • Platelet Transfusion
  • Pregnancy
  • Thrombocytopenia / diagnosis
  • Thrombocytopenia / epidemiology
  • Thrombocytopenia / immunology*
  • Thrombocytopenia / therapy*


  • Adrenal Cortex Hormones
  • Antigens, Human Platelet
  • Immunoglobulins, Intravenous
  • Isoantibodies
  • Isoantigens