Erythroblastosis Fetalis

erythroblastosis fetalis (ərĭth'rəblăstō`sĭs), hemolytic disease of a newborn infant caused by blood group incompatibility between mother and child. Although the Rh factor is responsible for the most severe cases of erythroblastosis fetalis, the disease may be produced by any of the other blood group antigens, such as those of the AOB system. With an Rh-negative mother and an Rh-positive father, the possibility exists that the fetus will be Rh positive. Microhemorrhages during gestation permit fetal red blood cells to enter the maternal circulation, causing an immunologic reaction that leads to sensitization of the mother against the Rh factor. Maternal antibodies against fetal red blood cell antigens pass through the placenta into the fetus, where an excessive destruction of fetal red blood cells occurs. When such hemolysis begins during pregnancy, stillbirth may result. While there is little danger of damage to the fetus during the first pregnancy, by the second pregnancy sufficient antibodies will have accumulated in the mother's bloodstream to cause increasing danger of hemolytic disease. The formation of maternal anti-Rh antibodies has been largely prevented in the United States by the injection of human immune globulin into the mother within 72 hours after delivery. This globulin contains antibodies against the Rh-positive fetal red blood cells, destroying them before the maternal bloodstream reacts by producing its own anti-Rh antibodies. Thus during the next pregnancy there will be few, if any, antibodies in the maternal bloodstream to destroy the fetal Rh-positive blood cells.

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erythroblastosis fetalis

 or hemolytic disease of the newborn

Anemia in an infant, caused when a pregnant woman produces antibodies to an antigen in her fetus's red blood cells. An Rh-negative woman (see Rh blood-group system) with an Rh-positive fetus whose ABO blood group (see ABO blood-group system) matches hers is likely to have an immune reaction after the first such pregnancy, which sensitizes her when fetal red blood cells enter her bloodstream, usually during labour. If blood typing shows incompatibility, an anti-Rh antibody injection given to the mother after the birth can destroy the fetal red cells, thus preventing trouble in a future pregnancy. If amniocentesis detects products of blood destruction, Rh-negative blood transfusions to the fetus before birth or exchange transfusion after it may save the baby's life. ABO incompatibilities are more common but usually less severe.

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erythroblastosis fetalis [ə‚rith·rə‚bla′stō·səs fē′tal·əs]

(medicine)

A form of hemolytic anemia affecting the fetus and newborn infant when a mother is Rh-negative and has developed antibodies against an Rh-positive fetus. Also known as hemolytic disease of newborn.

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Erythroblastosis Fetalis 

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.