Fetal hemoglobin has higher affinity for oxygen due to

Ans is 'a' i.e. Decreased 2, 3 DPG concentration The unique feature of fetal hemoglobin is that it has higher affinity for oxygen than adult hemoglobin.O2 saturation of the maternal blood in the placenta is so low that the fetus might suffer hypoxic damage if fetal redCells did not have a greater O2 affinity than adult red cells.This difference in O2 affinity between the two is because, fetal hemoglobin binds to 2, 3 DPG less effectively than adult hemoglobin.Binding of 2-3, DPG to the hemoglobin decreases its affinity for oxygen i.e., it shifts the O2dissociation curve to right.HbF reacts less with 2, 3 -DPG and so is able to bind O2 more tenaciously, accounting for the left shifted O2 dissociation curve at birth.Concentration of fetal hemoglobin at birth HbF - 70-80 % of total hemoglobin HbA - 30% of total hemoglobin