The Role of Folic Acid in Pregnancy
In 1992 the United States Public Health Service recommended pre-pregnancy folic acid, 400 mcg daily. The American College on Obstetrics and Gynecology agreed. This dose of folic acid has been shown to reduce the chance of neural tube defects (NTDs) by 36% in "normal" women. NTDs are birth defects of the brain and spine.
Four hundred micrograms (400mcg) of folic acid is found in the typical over-the-counter multivitamin sold in the supermarket or pharmacy. Strictly speaking, "prenatal vitamins" are not necessary, because the non-prescription "regular" vitamin has "enough" folic acid.
Prenatal vitamins make some women feel bad: constipation and stomach aches are common. Alternatives to the prenatal vitamin include a "regular" over the counter vitamin OR a children's chewable vitamin.