Fetal hemoglobin
（重定向自Foetal hemoglobin）
![Fetal hemoglobin protein structure, formed by 2 alpha subunits (top) and two gamma subunits (bottom), as well as their four heme groups. Each polypeptide chain (ribbon) is rainbow-colored from blue to red (N- to C-termini)](/Images/godic/202501/13/Hemoglobin_F5404.png")
![The oxygen saturation curve for fetal hemoglobin (blue) appears left-shifted when compared to adult hemoglobin (red) since fetal hemoglobin has a greater affinity for oxygen.](/Images/godic/202501/13/HbA_vs_HbF_saturation_curve5404.png")
![Increasing the body's production of fetal hemoglobin is used as a strategy to treat sickle-cell disease.](/Images/godic/202501/13/Sicklecells5404.jpg")
Fetal hemoglobin, or foetal haemoglobin, (also hemoglobin F, HbF, or α2γ2) is the main oxygen transport protein in the human fetus during the last seven months of development in the uterus and persists in the newborn until roughly 6 months old. Functionally, fetal hemoglobin differs most from adult hemoglobin in that it is able to bind oxygen with greater affinity than the adult form, giving the developing fetus better access to oxygen from the mother's bloodstream.