ERYTHROPOIESIS IN THE NEWBORN

The normal newborn infant displays active erythropoiesis at birth. Within a few days erythropoietic activity is greatly reduced and remains so for several weeks. During this time the occurrence of anaemia does not evoke an erythropoietic response comparable with that seen in older children. It has been suggested that diminished production of erythropoietin by the infant following transition from the hypoxic intrauterine environment to the atmosphere accounts for these observations. Technical and ethical limitations on plasma erythropoietin assays have prevented adequate study of the mechanisms controlling erythropoiesis in this age group, and urinary erythropoietin assays appeared to offer a feasible alternative. This paper describes urinary assays in normal and anaemic infants, giving details of the technique. The results were inconclusive. The reasons for this are discussed and further studies proposed.