Risk Factors of Neonatal Immune Thrombocytopenia in Pregnant Women Previously Diagnosed with ITP: Results from a French Nationwide Prospective Study

Background: Neonatal immune thrombocytopenia (NITP) is a well described complication in newborns of women with ITP. It is reported to occur in about 15% to 30% of neonates. Previous pregnancies with NITP or ITP refractory to splenectomy have been described as associated with NITP mostly in retrospective studies. Methods: We conducted a nationwide prospective multicenter observational case-control study (ClinicalTrials.gov NCT02892630). Thirty-three centers including in the network of ITP experts in France participated in the study. Over a two years period, we enrolled 180 pregnant women with a history of ITP diagnosed before pregnancy and 171 of them were followed up until the delivery. Neonatal platelet counts were available for 136 newborns. Risk factor for developing NITP were evaluated as well as NITP treatment and complications. Results: NITP defined as a platelet count Disclosures Haioun: Takeda: Honoraria; Novartis: Honoraria; Janssen: Honoraria; Gilead: Honoraria; Celgene: Honoraria; Amgen: Honoraria; Roche: Honoraria; Servier: Honoraria; Miltenyi: Honoraria. Mahevas: GSK: Research Funding. Michel: Rigel: Consultancy; Bioverativ: Consultancy; Alexion Pharmaceuticals: Consultancy. Godeau: Novartis: Honoraria; Amgen: Honoraria; Amgen: Research Funding; LFB: Honoraria.