Anemia and the Pregnant Woman
Iron deficiency occurs in 20% of pregnant women in developed countries. Even worse, 50% or more of women in nonindustrialized nations become iron deficient, and between 30 - 50% are deficient in folic acid. Severe anemia is associated with a higher mortality rate among pregnant women. Mild-to-moderate anemia, however, does not pose any elevated risk.
Pregnancy increases the risk for anemia in different ways:
- It increases the body's demand for folic acid and, therefore, poses a risk for deficiencies and an increased risk for megaloblastic anemia. Low levels of folate during pregnancy increase the risk of neural tube defects in newborns.
- It increases the body's demand for iron, thus posing a risk for iron deficiency anemia. Pregnant or nursing women require 30 mg of iron per day. Maternal iron deficiency anemia is associated with increased weight or size of the placenta, a condition that may later pose a risk for high blood pressure in the offspring. Pregnant women with low hemoglobin levels (the iron-bearing component in the blood) have an elevated risk for pre-term or low birth weight infants.
- Pregnancy is also associated with fluid retention, which in turn may produce high volumes of plasma (the fluid component of blood). This can dilute red blood cells, which may lead to anemia.
- After delivery, heavy bleeding, which occurs in 5 - 10% of women who have given birth, can cause symptoms of anemia.
Diagnosing of Iron Deficiency During Pregnancy
A diagnosis of iron deficiency is problematic in pregnant women. The standard test is a measurement of ferritin levels, which are low in most people with iron deficiency. Pregnant women, however, may have high ferritin blood levels into their third trimester but still be iron deficient. A newer test that measures a factor called serum transferrin receptor may prove to be a useful way of diagnosing iron deficiency in women. Researchers are also investigating Doppler ultrasonography as an imaging technique for detecting anemia in the fetus. Traditionally, fetal anemia is diagnosed through amniocentesis. Doppler ultrasonography is a non-invasive method that does not risk causing a miscarriage or a worsening of fetal anemia.
Preventing Anemia in Pregnant Women
Iron Supplements. For the past 40 years, iron supplements have been recommended for all pregnant women. This practice has been challenged recently, however. There is no clear-cut evidence that the mild iron deficiency in most pregnant women experience is harmful. In addition, iron supplements cause gastrointestinal side effects and may not be completely harmless.
Some experts suggest iron supplements for the following women:
- All pregnant women whose hemoglobin levels are less than 11 g/dl, and
- Pregnant women whose serum ferritin levels are low beginning in their 20th - 24th weeks of pregnancy.
Vitamin Supplements. Women who are trying to conceive, who are pregnant, and who are breastfeeding should take 400 mcg of folic acid a day. They should be sure this is folic acid and not folate. Folate is the natural form of folic acid, but 400 mcg supplements of folate are half as potent as the same dose of folic acid.
Pregnant and nursing women who are vegetarians should be sure to have supplements of folic acid and other B vitamins as well, since many of these nutrients are found primarily in animal products. Vitamin B12 deficiencies during pregnancy can also produce anemia in both mother and child.
Diets Rich in Vitamin C. Eating foods rich in vitamin C can help absorb iron.
Treating Anemia During Pregnancy
Pregnant women who become anemic and require treatment may be given oral iron supplements or transfusions in severe cases. Intravenous iron sucrose is a newer form of IV iron and may prove to be effective and safe for pregnant women with anemia.
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