a pathological condition of the fetus or newborn infant, characterized by the extramedullary reproduction and appearance in the blood of large numbers of erythroblasts and other immature red blood cells.
The condition is regarded as an indication of the immunological reconstruction of the infant’s organism. It may result from an incompatibility between the blood of the mother and that of the fetus, from certain infectious and hereditary diseases (for example, toxoplasmosis), or from such conditions as vitamin deficiency. The clearest manifestation of erythroblastosis fetalis is found when the blood of the mother and that of the fetus are incompatible with respect to the Rh factor; hence the term “hemolytic disease of the newborn,” often used as a synonym of erythroblastosis fetalis. Anemia is the principal symptom of the disease. Erythroblastosis fetalis can be diagnosed in utero through analysis of the amniotic fluid (paracentesis of the amniotic cavity). In case of a positive diagnosis, premature delivery is indicated in order to prevent the development of the disease in a severe form.
Exchange transfusion of the blood in the newborn is the most effective method of treatment. The development of erythroblastosis fetalis in second and subsequent pregnancies can be prevented by administering anti-Rh gamma globulin to primiparous mothers with Rh-negative blood within the first three days after delivery of an infant with Rh-positive blood or after abortion.