At least 3 mth but staying on daily regiment of folic acid is best recommended for any female of reproductive age

There's no absolute guidelines as to when you should start taking folic acid before getting pregnant but I tell my patients to take a prenatal vitamin containing folic acid at least six weeks before you start trying to conceive.

Atleast 3 months before trying to conceive.
Stay Healthy!

You need to start prenatal vitamins with folic acid about 3 months ahead of trying to conceive.

Doug Young, MD

There is no set time, but usually take Folic acid 400mcg while you are trying to conceive. This amount is usually in standard prenatal vitamins.

Sincerely,

Dr. Janice Alexander, RN, MD

Folic acid is most important in the first 6-12 weeks of pregnancy when the neurological system is being formed. But in order to have enough folic acid available it is ideal to start weeks before conception. Note that most prenatal vitamins have folic acid in them.