By eating a well-balanced diet, most women can get a good supply of the vitamins, minerals and nutrients needed for pregnancy. However, your doctor will likely prescribe a prenatal multivitamin supplement for you, since some of the nutrients in greatest demand during pregnancy — iron, calcium and folic acid — are usually in the shortest supply. Of course, most prenatal vitamins include other nutrients as well.
Even before pregnancy begins, many women are iron-deficient, and antacids for indigestion cut down on the body's ability to absorb iron even more. Phosphorus found in soft drinks and red meats cuts down on the body's ability to absorb calcium (which is abundant in milk products and certain green leafy vegetables).
Folic acid stored in your body has taken on new importance for women who wish to become pregnant. Recent studies find that folic acid may help to prevent certain birth defects, called neural tube defects. And if you were on birth control pills, your body's reserve of folic acid may have been depleted. But research in both the United States and Europe shows that using vitamin supplements rich in folic acid for at least 30 days before you get pregnant can reduce your risk of having a baby with a neural tube defect, such as spina bifida (where the spine is not fully closed, causing, in some cases, paralysis or impaired use of the legs) and anencephaly (a fatal abnormality where the brain and head do not develop normally).
All women of reproductive age need to be certain that they take at least 0.4 milligrams of folic acid daily. Many women are not getting sufficient folic acid from their diets. A recent study showed that women who took a folic acid supplement for one year prior to pregnancy reduced their risk of delivering a premature baby by 50 percent to 70 percent. Because pregnancy is often not planned, ideally you should start taking folic acid when you become sexually active. Standard multiple vitamins contain the amount you need, 0.4 milligrams.
If you already have had a baby with a neural tube defect, you should consult your doctor before attempting to conceive. The doctor may recommend that you take a larger amount of folic acid at least one month before pregnancy through the first three months of pregnancy. Studies show that higher amounts of folic acid reduce recurrences by more than 70 percent. The risk of giving birth to a baby with neural tube defects increases if you have diabetes or epilepsy.
Vitamin supplements are included in prenatal care because a pregnant woman needs at least these basic vitamin necessities: iron (60 milligrams), folic acid (0.8 milligrams), calcium (1,200 milligrams), vitamin A (6,000 I.U.), and vitamin D (400 I.U.). A vitamin supplement must be taken every day because your body is unable to store many of these elements.
Be sure to take prenatal vitamins only as prescribed by your doctor. Large doses of certain vitamins can be extremely toxic to you and your developing baby. For example, vitamin A and vitamin D, if taken in large doses, may cause birth defects. Vitamin B6, if taken in large amounts by a pregnant woman, can cause nerve problems.