Characterization of severity of hemolytic disease of the fetus and newborn due to Rhesus antigen alloimmunization

Results across 2 real-world US databases found that although most neonates affected by hemolytic disease of the fetus and newborn due to Rhesus antigen alloantibodies did not require intervention beyond phototherapy, nearly 7% experienced disease severity requiring invasive intervention or resulting in neonatal mortality. More severely affected neonates had lower gestational age at birth, higher rates of cesarean delivery and neonatal intensive care unit admission, and longer length of hospital stay at birth compared with minimally affected neonates. The HDFN Severity Index is a useful tool to characterize hemolytic disease of the fetus and newborn and may be valuable alongside guideline-driven care in subsequent pregnancies.