Hemoglobin is the oxygen-carrying substance
in red blood cells. Fetal hemoglobin (HbF) is the type of hemoglobin produced
by a fetus's body.
At birth, babies typically have half fetal hemoglobin and
half adult hemoglobin (HbA). After birth, HbF is gradually replaced by HbA.
Some people with sickle cell disease continue to produce some
HbF, which helps protect them from more severe complications of
the disease.
