Hemolytic disease of the fetus and newborn (HDFN) otherwise known as erythroblastosis fetalis, is a disease in which fetal and neonatal erythrocytes are destroyed by maternal IgG alloantibodies. Before the first RhD immunoprophylaxis was introduced as a treatment in 1968, HDFN affected 1% of all newborns worldwide and resulted in a mortality rate of 50% (Bowman, 2003). In developed countries with adequate prenatal care, stringent screening and prophylactic treatment have substantially reduced the incidence of HDFN (McCauley, 2017; Castleman, 2020). Despite receiving adequate anti-Rh(D) immunoprophylaxis, allosensitization still occurs in an estimated 1-3 per 1,000 Rh-negative women (de Haas et al., 2015; Hall and Avalakunta, 2020). Studies have demonstrated improved survival in severely anemic fetuses with intrauterine transfusion, with reported live birth rates after IUT ranging from 88.9-100% (Zwiers, 2017). However, this treatment confers risk for miscarriage or pre-term birth.
Evidence describing the epidemiology of HDFN is sparse. The proposed study is a descriptive analysis of HDFN patients identified in the PEDSnet database. Descriptive analyses include the epidemiology and natural history of infants with HDFN, including, where available, maternal characteristics, prenatal treatment utilization patterns, and longitudinal treatment and outcomes data.