How does fetal hemoglobin differ from adult hemoglobin in oxygen affinity?

Fetal hemoglobin, also known as hemoglobin F, is designed to efficiently extract oxygen from maternal blood, which is crucial for the developing fetus. The molecular structure of fetal hemoglobin differs from that of adult hemoglobin in that it contains two alpha and two gamma chains, unlike adult hemoglobin, which has two alpha and two beta chains. This structural difference results in fetal hemoglobin having a higher affinity for oxygen compared to adult hemoglobin.

This increased affinity allows fetal hemoglobin to bind oxygen more readily in situations where oxygen pressure is low, such as in the placenta. Consequently, this ensures that the fetus receives an adequate supply of oxygen necessary for growth and development, even when the maternal blood oxygen levels may not be exceptionally high. The relationship between maternal and fetal hemoglobin is critical and essential for efficient oxygen transfer during pregnancy, showcasing how the fetal respiratory system is adapted to its in utero environment.