Is fetal hemoglobin affect baby health?

Fetal hemoglobin is the main oxygen transport protein in the fetus during the last seven months of development in the womb. In newborns, fetal hemoglobin is nearly completely replaced by adult hemoglobin by approximately the twelfth week of postnatal life. By adulthood, only traces are found in the bloodstream. In some diseases ociated with abnormal hemoglobin production, fetal hemoglobin may persist in larger amounts. In babies, a high level of fetal hemoglobin is not harmful, but it could be caused by an underlying disease. It's only if it is elevated after age four that it should be investigated for cause.