Folic Acid Dosage During Pregnancy — 400 to 800 mcg

Two numbers apply here and they are not the same one. The supplement dose recommended in the United States is 400 to 800 mcg of folic acid a day, started at least a month before conception. The total intake target in pregnancy is 600 mcg DFE a day, counting food and supplement together. The selector below shows the intake target by life stage; the section under it explains the dose.

The intake target: 600 mcg DFE in pregnancy

The Recommended Dietary Allowance for folate is written in dietary folate equivalents, because folic acid from supplements and fortified food is absorbed better than folate from food. One DFE equals 1 mcg of food folate, or 0.6 mcg of folic acid taken with food, or 0.5 mcg of a supplement taken on an empty stomach.

Life stage	RDA (mcg DFE per day)
Children 4 to 8	200
Ages 14 and older, both sexes	400
Pregnancy	600
Lactation	500

The tolerable upper intake level for adults is 1,000 mcg a day of folic acid from supplements and fortified food — it applies to the synthetic form only, not to folate from food.

The supplement dose: 400 to 800 mcg, before conception

The 2023 USPSTF recommendation is the operative one for dosing, and it carries a Grade A: all persons planning to or who could become pregnant should take a daily supplement containing 0.4 to 0.8 mg (400 to 800 mcg) of folic acid, beginning at least one month before conception and continuing through the first two to three months of pregnancy.

Note who that covers. It is not addressed to pregnant people; it is addressed to anyone who could become pregnant, because nearly half of US pregnancies are unplanned and the neural tube closes in weeks three and four — often before a missed period. Waiting for a positive test misses the window the supplement exists to cover.

The recommendation also has an explicit exclusion: it does not apply to people who have had a previous pregnancy affected by a neural tube defect, or who are at very high risk for other reasons such as family history or folate-blocking medication. Those cases need a dose set in clinic, and it is a much higher one.

Food folate and fortification do part of the work

The United States has fortified enriched breads, flours, pasta, rice and cornmeal with folic acid since the late 1990s, and corn masa flour was added later — the reason a US diet already delivers folic acid without anyone choosing it. Food folate comes from dark leafy greens, asparagus, brussels sprouts, oranges and orange juice, beans, peas, nuts and beef liver.

The 2025–2030 Dietary Guidelines name folate among the top nutrient priorities of pregnancy, alongside iron and iodine, and advise talking to a clinician about a daily prenatal vitamin. That is the sentence that connects the two numbers on this page: fortification plus diet gets most people near the 600 mcg DFE target, and the supplement exists to guarantee the periconceptional window regardless.

The other nutrients that move in pregnancy

Iron is the one that changes most: the RDA jumps from 18 mg to 27 mg a day. Folate and iron work together in blood formation, and a deficiency in either produces anemia — see the daily iron intake numbers. Calcium, by contrast, does not rise in pregnancy at all, which surprises most people; the reason and the figures are on the daily calcium intake page. For the energy side of the same period, see pregnancy calorie needs.

This content is informational and does not replace prenatal care. Dose and timing are decided by your obstetric clinician.