Supplement manufacturers can make health claims if they are approved by the FDA. One example would be "adequate folic acid may reduce a woman's risk of having a child with a neural tube defect."

Anencephaly is a form of neural tube defect that is typically an isolated birth defect that is not related to chromosomal abnormalities.

If all women took adequate folic acid before conception and during pregnancy, the number of babies born with a neural tube defect could drop by as much as 70 percent.