Current recommendations

Recommendations from the U.S. Preventive Services Task Force

In 2009, the U.S. Preventive Services Task Force (USPSTF) reviewed available evidence on folic acid supplementation in women of childbearing age published since their 1996 recommendation. No studies have been published since 1996 that support a change in the previous recommendation, and the scientific studies clearly show that folic acid supplementation reduces the incidence of NTDs. No studies showed harm associated with taking folic acid. Although some studies reported increased twin pregnancies in women who take folic acid, careful analysis suggests that fertility treatments and not folic acid led to the twin pregnancies. 

The USPSTF recommends that “All women capable of pregnancy should take a daily vitamin supplement that contains 0.4 to 0.8 mg (400 to 800 µg) of folic acid.” This is a Grade A recommendation, which means there is high certainty that the net benefit is substantial. The USPSTF recommends that health care providers offer or provide this counseling to their patients. They also state in the recommendation that, “Many foods are now fortified with folic acid. It is not known whether women can get enough folic acid to prevent neural tube defects simply by eating folic acid–fortified food.”²

Recommendation from the National Academy of Sciences Institutes of Medicine (IOM) 

In 1998, the Food and Nutrition Board of the National Academy of Sciences Institute of Medicine (IOM) recommended that, to reduce their risk for an NTD-affected pregnancy, women capable of becoming pregnant should take 400 micrograms of synthetic folic acid daily from fortified foods or supplements or a combination of the two in addition to consuming food folate from a varied diet. From the report:

“Folate functions as a coenzyme in single-carbon transfers in the metabolism of nucleic and amino acids. The primary indicator used to estimate the Recommended Dietary Allowance (RDA) for folate is erythrocyte folate in conjunction with plasma homocysteine and folate concentrations. The RDA for both men and women is 400 mcg/day of dietary folate equivalents (DFEs). DFEs adjust for the nearly 50 percent lower bioavailability of food folate compared with that of folic acid: 1 mcg of dietary folate equivalent = 0.6 mcg of folic acid from fortified food or as a supplement taken with meals = 1 mcg of food folate = 0.5 mcg of a supplement taken on an empty stomach. To reduce the risk of neural tube defects for women capable of becoming pregnant, the recommendation is to take 400 mcg of folic acid daily from fortified foods, supplements, or both in addition to consuming food folate from a varied diet. The evidence available on the role of folate in reducing the risk of vascular disease, cancer, and psychiatric and mental disorders is not sufficiently conclusive to use risk reduction of these conditions as a basis for setting the Estimated Average Requirement (EAR) and the RDA. 

“In the U.S. adult population from 1988 to 1994, which was before cereal grains were fortified with folate, the reported median intake of folate from food was approximately 250 mcg/day, but this value underestimates current intake. The ninety-fifth percentile of intake from food and supplements was close to 900 mcg/day overall.”³

Other recommendations

American College of Obstetrics and Gynecology (ACOG): In 2003, an updated guideline from ACOG recommended periconceptual folic acid supplementation (400 mcg) in a multivitamin for most women capable of pregnancy.⁴

American Academy of Family Physicians (AAFP): For a woman planning to become pregnant who does not have a history of neural tube defects, the AAFP recommends prescribing folic acid supplementation of 400 to 800 mcg per day. The AAFP also recommends prescribing 400 mcg of folic acid supplementation to a woman of childbearing age if she is not planning a pregnancy.⁵

The American Academy of Pediatrics (AAP): The AAP endorses the U.S. Public Health Service recommendation that all women capable of becoming pregnant consume 400 mcg of folic acid daily to prevent neural tube defects, particularly for adolescent, sexually active women who do not plan to use effective contraception or abstain from sexual intercourse.⁶

American Academy of Neurology (AAN): Because of teratogenesis and impaired folate metabolism associated with certain antiepileptic drugs, the AAN recommends folic acid supplementation of no less than 400 mcg per day for women of childbearing age with epilepsy.⁷

Recommendation for those with a Medical history of neural tube defects: 

ACOG, AAFP, among other organizations recommend that women with a history of neural tube defects routinely take 400 mcg of folic acid daily and increase to 4mg per day one month prior to conception and through the first three months of pregnancy.