High Hemoglobin Levels in Newborn Babies and Later in Life

Newborn infants face some critical adaptations when they are born and start to breathe on their own, commencing a life in which they depend on their own bodies.

During the last seven months of pregnancy, an unborn human child has a functioning bloodstream without, of course, functioning lungs. The fetus can't gasp for breath when their oxygen levels become low. To compensate for the necessity of extracting oxygen from the mother's bloodstream after it has passed by other organs, unborn babies have a high-potency oxygen-binding form of the protein known as fetal hemoglobin, or HbF. 

This form of hemoglobin — a protein within red blood cells that carries oxygen around the organs and tissues — is very effective at binding to oxygen, so it the fetus gets all the oxygen it needs from the mother's blood during pregnancy. Fetal hemoglobin is not as effective at releasing that oxygen into the baby's bloodstream, however. Nor does it have to be. A baby in the womb isn't going to go snow skiing at high altitude or join a pickup basketball game that would require high oxygen levels. 

When the child is born, however, fetal hemoglobin becomes potentially problematic.

The baby now has to breathe on his own, but fetal hemoglobin is slow to release oxygen into the cells that need it. As long as the baby's blood contains mostly fetal hemoglobin, it will need more hemoglobin.

This is why the neonate's body begins to produce an "adult" form of hemoglobin known as Hb (or Hgb). Before the baby's body has replaced HbF with Hb, it needs high hemoglobin, at least 12 grams per deciliter, to function properly. After the baby's body has replaced HbF with Hb, it only needs 6 grams per deciliter to function normally. Not every baby, however, matures so anemia can be avoided even when hemoglobin levels fall.

What Is Hereditary Persistence of Fetal Hemoglobin?

Some people, however, lack a genetic "control switch" called BCL11A. This gene is responsible for stopping the production of "baby hemoglobin" HbF and starting the production of adult hemoglobin Hb. [1]

What kinds of complications can arise from having HbF that persists beyond infancy? Most authorities will tell you that hereditary persistence of hemoglobin in and of itself is a benign condition.

High fetal hemoglobin levels delay the symptoms of sickle cell disease in infants and toddlers [2]. Physicians sometimes even give sickle cell patients medications that deactivate BCL11A so they will have more energy because their blood carries more oxygen [3]. Adults who suffer oxygen deprivation at high altitudes adapt to the stress by producing more HbF [4].

But the persistence of high hemoglobin levels isn't always a good thing — and it can indeed lead to medical complications. Certain kinds of kidney tumors in children are associated with high, persistent levels of fetal hemoglobin [5]. If the body needs greater oxygen-carrying capacity in its hemoglobin after birth (if you spend time at high altitude, for instance, or you develop heart disease), it can restart the creation of HbF [6]. But you can also help the production of adult hemoglobin along by making sure that your baby has access to one simple elements of nutrition.

Zinc and HbF Hemoglobin Production: What Do You Need to Know?

The part of the BCL11A gene that can fail to function, so it does not activate the production of adult hemoglobin, is known as its "zinc finger". Babies whose mothers had zinc-deficient diets during pregnancy sometimes can't activate this gene, but people later in life who have full-blown hemoglobin disorders like beta-thalassemia and sickle cell disease sometimes suffer zinc-deficiency, too [7]. Zinc supplements aren't enough to activate a mutant gene, but they will help a normal gene perform its intended function [8].

If you are breastfeeding your baby, the best way to make sure that the baby gets enough zinc is for the mother to get enough zinc through her own diet [9]. You can do this by taking zinc supplements, but there's no need to overdose. Just 10 mg a day of zinc is enough to meet your needs, and 15 mg a day is tolerable, although 30 mg a day should be your upper limit. Too much zinc depletes copper.

t's also possible to get all the zinc you need from zinc-rich foods. Spinach doesn't have the most zinc of all the foods, but it's especially easy to work into your diet.

There's a very easy way to determine whether you need to take zinc. Place a zinc tablet on your tongue and let it dissolve. If your reaction is "eww," and the zinc tablet has a metallic taste, you don't need the supplement. But if you do need zinc, take up to 30 mg a day in consultation with your health care provider so that you can pass the mineral on to your baby through the breast milk. You will also be giving your child greater immunity against childhood diseases [10] and a healthier start in life if you ensure that they get adequate amounts of zinc.