Pregnant? Why you should take folic acid

Q: I hope to get pregnant this year. I eat plenty of fruit and vegetables as part of what I think is a well balanced diet. Do I need to take any vitamins?

A: Yes! You want to take between 400 to 800 micrograms of supplemental folic acid every day, starting now.

Daily folic acid supplementation starting at least one month prior to conception and continued for the first three months of pregnancy greatly reduces the risk of neural tube defects. Neural tube defects are a type of developmental abnormality of the nervous system, such as spina bifida.

Taking folic acid while pregnant may protect the baby in more ways than previously known. Two studies in the last month suggest additional benefits.

One study looked at 35,000 pregnancies. Some women said they took folic acid pills for at least a year before they got pregnant. These women had only half the average risk of premature birth. The other study, one in Canada, included more than one million newborns. This study found that heart defects in babies have been less common since Canada started adding folic acid to some foods.

Every woman who has any chance of becoming pregnant should take extra folic acid. The dose should be at least 400 micrograms per day. That’s the amount in a standard multiple vitamin.

For women who are actively trying to become pregnant, 800 micrograms is safe. It also may be slightly better at preventing spina bifida and other birth defects.

Women who’ve ever been pregnant with a baby affected by a neural tube defect should take a much higher dose of folic acid. The U.S. Centers for Disease Control and Prevention recommends 4,000 micrograms per day for these women. They should begin taking this higher dose at least a month before conception and continue it throughout the first three months of pregnancy.

For women who are trying to get pregnant, I recommend one multiple vitamin with iron and a 400 microgram folic acid supplement, for a total of 800 micrograms of folic acid daily. The other supplement to consider is additional iron if you have heavy menstrual periods or have ever been anemic.

(Howard LeWine, M.D. is a practicing internist and Chief Medical Editor of Internet Publishing at Harvard Health Publications, Harvard Medical School.)

(For additional consumer health information, please visit www.health.harvard.edu.)

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