Nutritional supplements that may be helpful during Pregnancy

Most doctors, many other healthcare professionals, and the March of Dimes recommend that all women of childbearing age supplement with 400 mcg per day of folic acid. Such supplementation could protect against the formation of neural tube defects (such as spina bifida) during the time between conception and when pregnancy is discovered.

The requirement for the B vitamin folic acid doubles during pregnancy, to 800 mcg per day from all sources. Deficiencies of folic acid during pregnancy have been linked to low birth weight and to an increased incidence of neural tube defects (e.g., spina bifida) in infants.

In one study, women who were at high risk of giving birth to babies with neural tube defects were able to lower their risk by 72% by taking folic acid supplements prior to and during pregnancy. Several preliminary studies have shown that a deficiency of folate in the blood may increase the risk of stunted growth of the fetus. This does not prove, however, that folic acid supplementation results in higher birth weights. Although some trials have found that folic acid and iron, when taken together, have improved birth weights, other trials have found supplementation with these nutrients to be ineffective.

The relationship between folate status and the risk of miscarriage is also somewhat unclear. In some studies, women who have had habitual miscarriages were found to have elevated levels of homocysteine (a marker of folate deficiency). In a preliminary study, 22 women with recurrent miscarriages who had elevated levels of homocysteine were treated with 15 mg per day of folic acid and 750 mg per day of vitamin B6, prior to and throughout their next pregnancy. This treatment reduced homocysteine levels to normal and was associated with 20 successful pregnancies. It is not known whether supplementing with these vitamins would help prevent miscarriages in women with normal homocysteine levels. As the amounts of folic acid and vitamin B6 used in this study were extremely large and potentially toxic, this treatment should be used only with the supervision of a doctor.

In other studies, however, folate levels did not correlate with the incidence of habitual miscarriages.

Preliminary and double-blind evidence has shown that women who use a multivitamin-mineral formula containing folic acid beginning three months before becoming pregnant and continuing through the first three months of pregnancy have a significantly lower risk of having babies with neural tube defects (e.g., spina bifida) and other congenital defects.

In addition to achieving significant protection against birth defects, women who take folic acid supplements during pregnancy have been reported to have fewer infections, and to give birth to babies with higher birth weights and better Apgar scores. (An Apgar score is an evaluation of the well-being of a newborn, based on his or her color, crying, muscle tone, and other signs.) However, if a woman waits until after discovering her pregnancy to begin taking folic acid supplements, it will probably be too late to prevent a neural tube defect.