The Rhesus factor.
D004899:Erythroblastosis, Fetal / Q000453:epidemiology*; D005260:Female; D005826:Genetics, Medical; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D012204:Rh-Hr Blood-Group System
D012204:Rh-Hr Blood-Group System