RHD and fetal erythroblastosis: The 3 study objectives were to estimate the live birth prevalence of all HDFN, Rh factor alloimmunized HDFN only, and clinically severe HDFN; to identify clinically significant risk factors for HDFN; and to determine the rates of clinical outcomes and treatments associated with newborns with HDFN when compared with healthy newborns and other sick newborns.