A condition characterized by the abnormal presence of ERYTHROBLASTS in the circulation of the FETUS or NEWBORNS. It is a disorder due to BLOOD GROUP INCOMPATIBILITY, such as the maternal alloimmunization by fetal antigen RH FACTORS leading to HEMOLYSIS of ERYTHROCYTES, hemolytic anemia (ANEMIA, HEMOLYTIC), general edema (HYDROPS FETALIS), and SEVERE JAUNDICE IN NEWBORN.

A disorder of the fetus or newborn that occurs when fetal cells that are coated with IgG alloantibodies from the mother attack antigens inherited from the father. Severity can range from absence of symptoms to death.