Anemia is a condition in which the oxygen-carrying capacity of the blood is reduced. Almost all living creatures on earth require oxygen to sustain life. In humans the blood is responsible for carrying oxygen to the cells of the body. Without oxygen, the cells die.

Anemia may be caused by many things. The most common cause in women of childbearing age is iron-deficiency (see Iron). The iron atom is a tiny, yet crucial, component of the hemoglobin molecule. Hemoglobin is a large protein found inside the red blood cell. Hemoglobin is responsible for the red color of blood. Oxygenated blood is bright red; de-oxygenated blood is more dark, blue-red in color. The iron content of hemoglobin determines how much oxygen can be carried by the hemoglobin in a red cell. If this amount becomes too low, the blood cannot carry adequate oxygen, and the cells of the body receive less than they need.

When the total amount of iron-rich hemoglobin drops below a certain level, a person becomes anemic. The most common symptom of anemia is fatigue. Since most pregnant women experience fatigue from early on in pregnancy, anemia can compound this tiredness. As anemia worsens, a person may experience headaches.

In prolonged anemia, the general health of the body deteriorates. The body is less able to deal with the demands of life, including resistance to disease. Prior to modern times in the U.S. (and even today in some impoverished areas of the world), many young women succumbed to relatively minor infections after years of anemia due to repeated childbirth and poor diet.

During pregnancy, there is an increased demand for iron. Iron is needed for the baby’s blood (and placenta) and an increase in the mother’s blood volume. The mother also needs iron in storage in the event that she hemorrhages after delivery. If the total, additional iron requirements of both the mother and baby during pregnancy are measured, this requirement is just over a gram of iron. Fortunately, unborn babies are parasites for their own iron needs. But this comes at a cost to the mother’s iron needs. Nutritional scientists feel that the demands for iron during pregnancy (for both mother and baby) cannot be met by diet alone.

If a pregnant woman does not consume extra iron during pregnancy, she will have less iron in her body after pregnancy. Not much additional iron is needed early in pregnancy, but in the second half of pregnancy, the body needs about 15 mg per day of “elemental” iron. Most prenatal multi-vitamins try to include this amount of iron. However, the body does not absorb all of the iron that passes through the stomach and intestines. Also, iron may upset the digestive tract causing nausea, constipation and black stools.

If a woman is anemic during pregnancy, it may be necessary to take much larger amounts of iron. Fortunately, late in pregnancy, the body is able to absorb iron more easily. Oddly the compounds of iron commonly used in supplements are more absorbable than some natural forms of iron. Animal sources of iron (meat) are easily absorbed. However, the state of the iron atom in vegetables (called the “ferric” state) is less available for use by the human body. Vitamin C helps convert vegetable sources of iron to the more absorbable “ferrous” form of the iron atom. This may be an important point for vegetarian women, especially if they have iron-deficiency anemia.

Although dietary iron compounds (like ferrous sulfate, ferrous gluconate and ferrous fumarate) are often prescribed in pregnancy in doses of over several hundred milligrams, this is probably unnecessary, and may cause other problems. High doses of iron may block other nutrients (for example, zinc and copper). Also, during the state of anemia, the intestines adjust to allow iron to be more easily absorbed. In addition, about one-third of women cannot tolerate large doses of iron due to nausea and stomach upset.

If you need an iron supplement to correct anemia, try one of the three common iron compounds (above) until you find one that your body tolerates best. Take as much as you can tolerate without side effects (nausea, constipation, etc….). However, a woman probably does not need more than about 300 mg per day. This amount should meet the additional requirements of pregnancy, and begin to re-build your blood and iron stores without affecting the absorption of other essential nutrients. Consult the list (under Iron) of iron-rich foods, and if you are vegetarian, take some additional vitamin C when you eat vegetable sources of iron (100-200 mg should be plenty).

Other Forms of Anemia
Not all anemia is due to iron deficiency. Megaloblastic anemia is caused by a deficit of either vitamin B12 or the vitamin, folic acid. This form of anemia is relatively rare. Vitamin B12 is stored in the liver for long periods of time, and not much is needed by the body. But it is an essential nutrient. Thus, the body cannot produce it; it must be consumed. After many years, strict vegetarians (“vegans”) may develop a B12 deficiency. Persons unable to produce “intrinsic factor”, those with Crohn’s disease, or those who have had portions of the small intestine removed, may not be able to absorb B12 either.