Risk factors for severe neonatal thrombocytopenia in cases of maternal immune thrombocytopenia

Maternal immune thrombocytopenia (ITP) may induce neonatal thrombocytopenia (nTP), which carries a risk of neonatal haemorrhagic complications. Some risk factors for nTP have reached consensus such as maternal splenectomy and previous severe nTP, while others such as maternal platelet count have not.We conducted a retrospective cohort study in a university hospital, including 145 neonates of mothers with ITP. We assessed the risk of severe nTP and bleeding complications.Severe nTP in the first 24 h after birth was more common in case of maternal splenectomy (OR = 4.4) and a previous severe nTP (OR = 46.9). Severe nTP at nadir (lowest platelet count during the initial postnatal days) was more frequent in cases of a previous neonate with severe nTP (OR = 42), maternal treatment during pregnancy (OR = 2.4) and a low maternal platelet count during pregnancy or at delivery. These risk factors were not significantly associated with an increased risk of neonatal haemorrhagic complications.In our population, we confirm the risk of severe nTP in case of maternal splenectomy or previous nTP. By monitoring the platelet count to its nadir, we identified three additional risk factors: maternal treatment during pregnancy and low maternal platelet count during pregnancy or low maternal platelet count at delivery.