e·ryth·ro·blas·tic a·ne·mi·a. anemia characterized by the presence of large numbers of nucleated red blood cells (normoblasts and erythroblasts) in the peripheral blood. Seen in newborns with hemolytic anemia, due to isoimmunization, such as that caused by Rh or ABO incompatibility. See also: erythroblastosis fetalis.