PERSISTENCE AND UTILIZATION OF MATERNAL IRON FOR BLOOD FORMATION DURING INFANCY 12

Abstract

Investigations of maternal blood and red cell volume by means of injected Fe55 during pregnancy (previously published from these laboratories) offered opportunity to follow the transplacentally obtained Fe in the blood of 16 infants studied from birth to a maximum of 32 months of age. As a group the infants showed no appearance of dietary Fe in hemoglobin until 3-4 months after birth. At some time between 6 months and 1 year, most gave evidence of utilization for hemoglobin of about 20% more transplacental Fe than was in hemoglobin at birth. By 2 years of age the mean amount of all transplacental Fe present in circulating hemoglobin was calculated to be 90% of the mean at birth. The one (36-week) premature infant of the group not only failed to show any appear-ance of "stored" transplacental Fe at any time during 32 months of observations but showed evidence of some dietary Fe in hemoglobin as early as 65 days after birth. The normal infant at 2 years has [image]115 g of circulating hemoglobin, of which [image]70g are made from dietary and [image]45 g from transplacental iron.