Hemoglobin A

What happens to the genes for fetal hemoglobin after birth?

Shortly after the time of birth there is a switch from predominant expression of HbF to adult hemoglobin (HbA), which is mediated by a transcriptional switch in definitive erythroid progenitors from γ- to β-globin (Fig. 1).

Why do babies have different hemoglobin?

The reason this anemia occurs is that baby’s body is growing fast and it takes time for red blood cell production to catch up. The body breaks down red blood cells too quickly. This problem is common when the mother’s and baby’s blood types do not match. This is called Rh/ABO incompatibility.