LAUSR

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is the platelet counterpart of hemolytic disease of the newborn. Most severe cases of FNAIT are caused by antibodies against human platelet antigen‐1a (HPA‐1a). HPA‐1a–negative women giving birth to an HPA‐1a–positive child are at risk of becoming HPA‐1a–immunized, particularly women who are HLA‐DRB3*01:01–positive. The aim of the study was to estimate the risk of HPA‐1a–immunization in both HPA‐1a–negative/HLA‐DRB3*01:01–positive and HPA‐1a–negative/HLA‐DRB3*01:01–negative women after delivery of an HPA‐1a–positive child.