Perinatal management of neonatal alloimmune thrombocytopenia associated with anti-group A antibody

SUMMARY Objective To prevent neonatal alloimmune thrombocytopenia due to anti‐group A antibody perinatal management was performed. Background We previously reported a case of severe intracranial haemorrhage associated with neonatal alloimmune thrombocytopenia due to anti‐group A isoantibody. Material/Methods A 40‐year‐old Japanese woman, gravida 4 para 1, was pregnant with her second baby. The previous sibling developed severe thrombocytopenia and died 10 days after birth due to intracranial haemorrhage. He was diagnosed with neonatal alloimmune thrombocytopenia; the causative antibody was found to be the anti‐group A antibody. Prednisone was started at 7 weeks' gestational age. Intravenous immunoglobulin 1 g kg−1 week−1 was started at 29 weeks' gestational age and continued to delivery. Serological studies and genotyping were performed. Results The second boy was delivered at 33 weeks' gestational age by caesarean section. He was discharged without intracranial haemorrhage or thrombocytopenia. The anti‐group A antibody titre in the maternal serum was 2048–4096 (normal range: 4–64). The anti‐group A antibody titre in the newborn's serum was 4. Cross‐matching between the maternal serum and the paternal platelets was positive. Conclusion Owing to the history of neonatal alloimmune thrombocytopenia causing intracranial haemorrhage and death of the previous sibling, strict follow‐up of the subsequent pregnancy was conducted.