Birth Defects and Supplemental Vitamins.

Women of childbearing age who are capable of becoming pregnant should ingest 0.4 mg of folic acid per day to reduce the incidence of neural tube defects (anencephaly, spina bifida, and encephalocele). This may also reduce the incidence of conotruncal heart defects, limb defects, renal anomalies, pyloric stenosis, and possibly oral-facial clefts. Women who are at increased risk of having an affected fetus because of having had a previously affected fetus should take 4 mg of folic acid daily. Women with epilepsy, particularly those taking antiepileptic drugs, should follow the same guidelines as nonepileptic women; however, women with epilepsy should take the lowest dose and the fewest number of antiepileptic drugs needed to control the epilepsy. Physicians and the public should be educated about the benefits of supplemental folic acid and the consumption of folate-rich foods and fortified foods in reducing the incidence of neural tube defects and other congenital anomalies. They should be made aware that neural tube defects occur between 23 and 28 days of gestation, often before women know they are pregnant. Therefore, folic acid supplements need to be taken at least 1 month before the beginning of pregnancy. Because many pregnancies are unplanned, women should take folic acid supplements routinely.