Fetal Hemoglobin - A Mystery, a Need and a Cancer Marker

Hemoglobin is the main oxygen carrier in our blood, but the type of hemoglobin found in fetus can strongly bind to oxygen when compared with adult hemoglobin. Thus fetal hemoglobin and adult hemoglobin are the two basic types of hemoglobin found in humans. Fetus inside womb have only fetal hemoglobin. Just 1% of adult's hemoglobin is fetal hemoglobin. Just after birth, kid's stop the production of fetal hemoglobin due to some genetic changes, and within months percentage of adult hemoglobin start to rise.

Why do fetus have fetal hemoglobin ?

This fetal hemoglobin is a necessity of fetus, otherwise it can't get oxygen. Lungs of a fetus don't work inside mother's womb, and it can only absorb oxygen from mother's blood which is available till placenta. In placenta, mother's blood and fetus's blood only have a thin membrane between them, and oxygen passes through it as fetal hemoglobin attracts is more than mother's adult hemoglobin. If both fetus and mother have same hemoglobin than oxygen will not be transported to fetus and it will die of suffocation. Oxygen transfusion through the thin membrane inside placenta happens just like oxygen is absorbed by our blood inside lungs.

At what time production of fetal hemoglobin begins ?

In fetus production of fetal hemoglobin begins in 6th week, by 3 months it becomes the main type of hemoglobin found in fetus. Around completion of 40th week, which is around the time of birth, production of adult hemoglobin begins. By the age of 6 months after birth, adult hemoglobin becomes the predominant type. By the age of an year, percentage of fetal hemoglobin reaches the levels of an adult.

Note: Some genetic abnormalities can fail the switch from fetal to adult hemoglobin and the child lives with fetal hemoglobin. This condition is known as hereditary persistence of fetal hemoglobin (HPFH).

Why adults don't have fetal hemoglobin ?

If an adult female have fetal hemoglobin, then oxygen won't pass onto fetus, as both mother and fetus will have fetal hemoglobin and similar force to absorb oxygen. In such case fetus will die due to oxygen deficiency.

Now some of you might think that fetal hemoglobin won't harm a man in adulthood, but its not so. Due to better power to attach oxygen to itself, fetal hemoglobin makes it harder for body tissue to extract oxygen from blood. It makes the body oxygen-deprived in spite of having sufficient oxygen in air. In most of the cases even high levels of fetal hemoglobin remain unnoticed and often diagnosed while testing for other diseases. But such people feel less energetic than others. If percentage of fetal hemoglobin rises above 70% then it becomes harder to survive without regular blood transfusion.

Is Fetal Hemoglobin a marker for Cancer ?

Yes it is ! Some researcher have found that in cancer patients, fetal hemoglobin is generally found in newly formed blood vessels of cancerous tumors. It makes the cancerous tumor grow easily by extracting more oxygen from blood. Cancerous tissues don't directly produce F-cells or fetal hemoglobin, but it it makes some changes in biological environment of the affected area and utilizes the power of fetal hemoglobin to grow more rapidly.

So fetal hemoglobin is a need of our body to grow in mother's womb. It is mystery that how our body starts producing it while still in womb and how it stops just before birth, to live a normal life. It is again a mystery that how cancerous cells utilize our body's ability to produce fetal hemoglobin and use it as a better fuel to infect our body.