Why do newborn have higher hemoglobin than adults?

Newborns have higher hemoglobin levels than adults primarily due to the need for efficient oxygen transport during fetal development, as they rely on the placenta for oxygen. This fetal hemoglobin (HbF) has a higher affinity for oxygen than adult hemoglobin (HbA), allowing newborns to extract oxygen more effectively from maternal blood. After birth, hemoglobin levels gradually decrease as the infant's body transitions to producing adult hemoglobin and as the effects of maternal blood diminish.