Erythropoiesis is reduced to zero in the mouse by repeated homologous red cell transfusion.
Mating of transfusion-induced polycythemic mice was allowed, and observations were made on maternal and fetal erythropoiesis. It was observed that erythropoiesis in the pregnant, polycythemic mouse was suppressed throughout pregnancy, this observation suggesting that erythropoietin production was concomitantly suppressed.
Erythropoiesis in the fetuses of polycythemic mothers was initiated by 10 days and maintained in an active state throughout fetal life. Hematologic values of these fetuses at birth were higher than those of the newborn normal pregnant mice of the same strain.
It is possible that the fetus initiates and maintains erythropoietin independently of erythropoietin from the maternal circulation. The higher hematologic values of the newborn of polycythemic mothers are probably the result of the greater availability of iron from the breakdown of transfused cells, since it was found that comparable hematologic values were achieved in the newborn when iron-dextran (Imferon) was injected into the maternal tissues during pregnancy.