Taking folic acid before and during pregnancy can reduce the risk of certain birth defects. These include spina bifida, anencephaly, and some heart defects.
Experts recommend women who can become pregnant or who plan to become pregnant take at least 400 micrograms (mcg) of folic acid every day.
This is because many pregnancies are unplanned. Also, birth defects often occur in the early days before you may know you are pregnant.
If you become pregnant, you should take a multivitamin with 600 mcg of folic acid. Taking a multivitamin with folic acid helps ensure that you get all the nutrients you need during pregnancy.
Women who have had a baby with a neural tube defect may need a higher dose of folic acid. If you have had a baby with a neural tube defect, you should take 400 micrograms of folic acid every day, even when you are not planning to become pregnant. If you plan to become pregnant, you should talk to your doctor about whether you should increase your folic acid intake to 4 milligrams (mg) each day during the month before you become pregnant until at least the 12th week of pregnancy.
Prevention of birth defects with folic acid (folate)
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U.S. Preventive Services Task Force. Folic acid for the prevention of neural tube defects: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med. 2009;150:626-31. PMID: 19414842 www.ncbi.nlm.nih.gov/pubmed/19414842.
Update Date 4/15/2015
Updated by: Irina Burd, MD, PhD, Assistant Professor of Gynecology and Obstetrics at Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.