Folic Acid
Vitamin & mineralAlso called · 9 names▾▴
folate, vitamin B9, Vitamin B9, folacin, methylfolate, L-methylfolate, 5-MTHF, L-5-MTHF, 5-methyl-folate
Vitamin B9 supplement
Herbs and supplements are not FDA-approved before sale. About these sources
- Capsule/tablet
Research strength: 5 / 5
CDC recommends 400 mcg of folic acid daily for people who could become pregnant; the USPSTF recommends 400 to 800 mcg, starting 1 month before conception through the first 2 to 3 months. MotherToBaby says recommended amounts have not been found to raise the chance of birth defects, and trials support folic-acid-containing supplements for neural tube defect prevention; Czeizel tested a multivitamin containing folic acid, not folic acid alone. After a prior pregnancy affected by a neural tube defect, CDC and ACOG describe 4,000 mcg (4 mg) daily but differ on the start time: 1 month before conception at CDC and 3 months at ACOG; NIH ODS summarizes 4,000 to 5,000 mcg/day for high-risk cases. NIH ODS lists the pregnancy folate RDA as 600 mcg of folate per day, measured as dietary folate equivalents (DFE), and the upper limit for synthetic folic acid from supplements and fortified foods as 1,000 mcg/day for adults or 800 mcg/day for ages 14 to 18; it says medically supervised high-dose use is outside that limit. EMA lists a cancer-risk signal for high-dose folic acid at 1 mg or more for monitoring; EMA says a signal does not mean the medicine caused the event. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Folic Acid | Folate fact sheetTeratology service
- U.S. Preventive Services Task Force: Folic Acid Supplementation to Prevent Neural Tube Defects
- CDC: Folic Acid: Facts for CliniciansUS government
- ACOG FAQ: Healthy Eating During PregnancyProfessional society
- NIH ODS: Dietary Supplements and Life Stages: PregnancyUS government
- NIH ODS: Folate Health Professional Fact SheetUS government
- EMA PRAC recommendations on signals adopted at the 1-4 September 2025 meetingEU agencyEuropean guidance
- EMA: PRAC recommendations on safety signalsEU agencyEuropean guidance
- MRC Vitamin Study Research Group: Prevention of neural tube defectsUS government
- Czeizel and Dudás: Prevention of first occurrence of neural-tube defects by periconceptional vitamin supplementationUS government
Research strength: 5 / 5
MotherToBaby reports that folic acid at recommended amounts has not been found to increase the chance of birth defects and that folic acid can reduce neural tube defect risk when used before and during pregnancy. NIH ODS lists the pregnancy folate RDA as 600 mcg of folate per day, measured as dietary folate equivalents (DFE) and an upper limit for synthetic folic acid from supplements and fortified foods of 1,000 mcg/day for adults or 800 mcg/day for ages 14 to 18; it says medically supervised high-dose use is outside that limit. The USPSTF recommends 400 to 800 mcg/day for people who could become pregnant, with its stated prevention window ending in the first 2 to 3 months; for a prior pregnancy affected by a neural tube defect, CDC and ACOG describe 4,000 mcg/day through the first 3 months, beginning 1 month before conception at CDC and 3 months before at ACOG. NIH ODS summarizes 4,000 to 5,000 mcg/day for people at high NTD risk, a separate clinician-directed use. EMA lists a high-dose cancer-risk signal at 1 mg or more for monitoring; EMA says a signal does not mean the medicine caused the event. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Folic Acid | Folate fact sheetTeratology service
- U.S. Preventive Services Task Force: Folic Acid Supplementation to Prevent Neural Tube Defects
- CDC: Folic Acid: Facts for CliniciansUS government
- ACOG FAQ: Healthy Eating During PregnancyProfessional society
- NIH ODS: Dietary Supplements and Life Stages: PregnancyUS government
- NIH ODS: Folate Health Professional Fact SheetUS government
- EMA PRAC recommendations on signals adopted at the 1-4 September 2025 meetingEU agencyEuropean guidance
- EMA: PRAC recommendations on safety signalsEU agencyEuropean guidance
- MRC Vitamin Study Research Group: Prevention of neural tube defectsUS government
- Czeizel and Dudás: Prevention of first occurrence of neural-tube defects by periconceptional vitamin supplementationUS government
Research strength: 5 / 5
MotherToBaby says recommended amounts have not been found to increase birth-defect risk, and folic acid reduces neural tube defect risk when used before and during pregnancy. NIH ODS lists a pregnancy folate RDA of 600 mcg per day, measured as dietary folate equivalents (DFE), separate from the supplement amount, and an upper limit for synthetic folic acid from supplements and fortified foods of 1,000 mcg/day for adults or 800 mcg/day for ages 14 to 18; it says medically supervised high-dose use is outside that limit. The USPSTF's stated prevention period is before conception through the first 2 to 3 months; CDC and ACOG describe higher 4,000 mcg/day regimens for a prior pregnancy affected by a neural tube defect through the first 3 months, with different preconception start times. NIH ODS summarizes a 4,000 to 5,000 mcg/day range for people at high risk of neural tube defects; this is distinct from the routine-dose recommendation. EMA is monitoring a cancer-risk signal for doses of 1 mg or more and states that a signal does not mean the medicine caused the event. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Folic Acid | Folate fact sheetTeratology service
- U.S. Preventive Services Task Force: Folic Acid Supplementation to Prevent Neural Tube Defects
- CDC: Folic Acid: Facts for CliniciansUS government
- ACOG FAQ: Healthy Eating During PregnancyProfessional society
- NIH ODS: Dietary Supplements and Life Stages: PregnancyUS government
- NIH ODS: Folate Health Professional Fact SheetUS government
- EMA PRAC recommendations on signals adopted at the 1-4 September 2025 meetingEU agencyEuropean guidance
- EMA: PRAC recommendations on safety signalsEU agencyEuropean guidance
- MRC Vitamin Study Research Group: Prevention of neural tube defectsUS government
- Czeizel and Dudás: Prevention of first occurrence of neural-tube defects by periconceptional vitamin supplementationUS government
Folic Acid — Breastfeeding
Research strength: 4 / 5
MotherToBaby recommends 500 mcg of folic acid daily while breastfeeding; NIH ODS lists the lactation folate RDA as 500 mcg per day, measured as dietary folate equivalents (DFE). Page et al.'s 2017 study measured breast milk from 561 Canadian mothers and found total milk folate was 18% higher among supplement users; it measured milk composition, not infant health outcomes. NIH ODS sets an adult upper limit of 1,000 mcg/day of synthetic folic acid from supplements and fortified foods or 800 mcg/day for ages 14 to 18; it says medically supervised high-dose use is outside that limit. EMA lists a high-dose cancer-risk signal at 1 mg or more for monitoring, while noting that a signal does not mean the medicine caused the event. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Folic Acid | Folate fact sheetTeratology service
- NIH ODS: Folate Health Professional Fact SheetUS government
- Page et al.: Total folate and unmetabolized folic acid in the breast milk of Canadian womenUS government
- EMA PRAC recommendations on signals adopted at the 1-4 September 2025 meetingEU agencyEuropean guidance
Pregnancy
The USPSTF recommends 0.4 to 0.8 mg (400 to 800 mcg) of folic acid daily for people planning or able to become pregnant, beginning at least 1 month before anticipated conception and continuing through the first 2 to 3 months. CDC recommends 400 mcg daily for people who could become pregnant, and 4,000 mcg daily after a prior NTD-affected pregnancy from 1 month before conception through the first 3 months. ACOG describes 4 mg daily after a child with an NTD, starting at least 3 months before pregnancy through the first 3 months. NIH ODS summarizes 4,000 to 5,000 mcg/day for people at high NTD risk; it notes these doses exceed the UL and are for medical supervision. The USPSTF found adequate evidence that usual-dose supplementation is not associated with serious harms, and MotherToBaby says recommended amounts have not been found to increase birth-defect risk. The MRC Vitamin Study randomized 1,817 women with a prior NTD-affected pregnancy; 1,195 had a completed pregnancy with a known NTD outcome. It reported 6 NTDs in folic-acid groups and 21 in other groups, a 72% protective effect, but the abstract does not state the dose. Czeizel and Dudás confirmed 4,753 pregnancies and tested a daily multivitamin containing 0.8 mg folic acid, not folic acid alone; they reported 6 NTD cases in the trace-element group and none in the vitamin group. The 2026 Yoo umbrella review included 283 systematic reviews and searched evidence through Feb 2024. The Aug 2026 Shi prospective cohort included 6,578 first-trimester participants and found lower maternal RBC 5-MTHF associated with birth defects; it measured folate status rather than supplement use and does not establish a supplement-dose effect.
Breastfeeding
MotherToBaby states that folate is found naturally in breast milk and recommends 500 mcg/day of folic acid while breastfeeding. NIH ODS lists a 500 mcg DFE/day folate RDA during lactation and a synthetic folate UL of 1,000 mcg/day for adults or 800 mcg/day for ages 14 to 18 from supplements and fortified foods; it says the UL does not apply to high-dose supplemental folate under medical supervision. Page et al. (2017) cross-sectionally measured breast-milk folate species in 561 Canadian mothers, including 401 supplement users and 160 nonusers. Total breast-milk folate was 18% higher in supplement users, but the study measured milk chemistry rather than infant clinical outcomes. The authors concluded doses above 400 mcg may not be warranted in populations with mandatory fortification; this is an interpretation of milk composition, not a measured infant effect. Direct infant benefits or harms from maternal folic-acid supplementation through milk are not established by this study.
Folic acid is the synthetic form of folate, a B vitamin, and is used in most supplements and fortified foods. Natural folate is also present in food. NIH ODS describes folate as a nutrient involved in cell division and nucleic-acid synthesis. Pregnancy folate reference amounts are expressed as dietary folate equivalents, while the upper limit applies to synthetic folic acid from supplements and fortified foods.
What was tested
The pregnancy evidence includes randomized trials, guideline reviews, and observational studies. The MRC trial tested folic acid in women with a previous affected pregnancy but its abstract does not report the dose. The Czeizel trial tested a multivitamin containing 0.8 mg folic acid. The 2026 Beijing cohort measured red-cell and plasma 5-MTHF, not randomized supplement assignment. The 2017 Canadian study measured breast-milk folate species and supplement use, not infant health outcomes. The 2026 umbrella review synthesized earlier systematic reviews with a search end date of Feb 2024.
What high-dose folic acid regimen and preconception start time applies after a prior NTD-affected pregnancy?
- Source A says
- CDC describes 4,000 mcg/day beginning 1 month before trying to conceive and continuing through the first 3 months. ACOG describes 4 mg/day beginning at least 3 months before pregnancy and continuing through the first 3 months. (CDC: Folic Acid: Facts for Clinicians, ACOG FAQ: Healthy Eating During Pregnancy)
- Source B says
- NIH ODS summarizes 4,000 to 5,000 mcg/day for people at high risk of neural tube defects and cites a preconception start of 1 to 3 months. It notes that the Food and Nutrition Board has not issued a recommendation for people with a previous NTD-affected pregnancy. (NIH Office of Dietary Supplements: Dietary Supplements and Life Stages: Pregnancy)
- Why they differ
- CDC and ACOG address a prior affected pregnancy and specify 4 mg with different preconception timing. NIH ODS summarizes a broader high-risk range from expert recommendations. The reviewed sources do not explain the reason for the different start times or dose range.
- What the evidence shows overall
- The entry preserves the source-specific dose, population, and timing instead of choosing one regimen. These differences do not change the routine-dose rating.
How should the 2025 EMA high-dose folic acid cancer signal be described?
- Source A says
- EMA PRAC lists increased cancer risk with high-dose folic acid at 1 mg or more and recommends monitoring in periodic safety update reports. (EMA PRAC recommendations on signals adopted at the 1-4 September 2025 meeting)
- Source B says
- EMA says the presence of a safety signal does not mean that a medicine caused the reported adverse event. CDC and ACOG continue to describe specific folic acid regimens for NTD prevention, including high-risk use. (EMA: PRAC recommendations on safety signals, CDC: Folic Acid: Facts for Clinicians, ACOG FAQ: Healthy Eating During Pregnancy)
- Why they differ
- The PRAC recommendation is a signal for monitoring, while EMA's signal page explains that a signal does not establish causation. The pregnancy guidelines address NTD prevention and do not assess the cause of the cancer signal.
- What the evidence shows overall
- The entry reports the EMA signal and its monitoring status without stating that causation is established. The signal alone does not change the compatible rating for routine recommended amounts under R1.
- The USPSTF recommends 400 to 800 mcg of folic acid daily for people planning or able to become pregnant, starting at least 1 month before conception and continuing through the first 2 to 3 months. (U.S. Preventive Services Task Force)
- CDC describes 4,000 mcg daily after a prior NTD-affected pregnancy, beginning 1 month before trying to conceive and continuing through the first 3 months. (CDC)
- ACOG describes 4 mg daily after a child with an NTD, beginning at least 3 months before pregnancy and continuing through the first 3 months. (American College of Obstetricians and Gynecologists)
- MHRA advises offering 5 mg per day before any possibility of pregnancy to a person planning pregnancy while taking any antiepileptic drug; the page also calls for specialist advice about antiepileptic treatment. (UK Medicines and Healthcare products Regulatory Agency)
General research, not specific to pregnancy.
Folate is vitamin B9 and is involved in cell division and the body's use of amino acids. NIH ODS lists an adult folate RDA of 400 mcg DFE/day and an upper limit for synthetic folic acid from supplements and fortified foods.
- NIH ODS lists a folate RDA of 400 mcg DFE/day for adults and an upper limit of 1,000 mcg/day for synthetic folate from supplements and fortified foods for ages 19 and older, and 800 mcg/day for ages 14 to 18. The upper limit does not apply to high-dose supplemental folate under medical supervision. (NIH Office of Dietary Supplements: Folate Health Professional Fact Sheet)
- MotherToBaby: Folic Acid | Folate fact sheetTeratology serviceSecondary
- U.S. Preventive Services Task Force: Folic Acid Supplementation to Prevent Neural Tube DefectsSecondaryPage dated 2023-08-01Independent check
- CDC: Folic Acid: Facts for CliniciansUS governmentSecondaryPage dated 2026-07-15Independent check
- ACOG FAQ: Healthy Eating During PregnancyProfessional societySecondaryIndependent check
- NIH Office of Dietary Supplements: Dietary Supplements and Life Stages: PregnancyUS governmentSecondaryPage dated 2025-04-03Independent check
- NIH Office of Dietary Supplements: Folate Health Professional Fact SheetUS governmentSecondaryPage dated 2022-11-30Independent check
- EMA PRAC recommendations on signals adopted at the 1-4 September 2025 meetingEU agencySecondaryPage dated 2025-09-29European guidance
- EMA: PRAC recommendations on safety signalsEU agencySecondaryEuropean guidance
- UK MHRA Drug Safety Update: Pregabalin findings of safety study on risks during pregnancyUK governmentSecondary
- MRC Vitamin Study Research Group: Prevention of neural tube defectsUS governmentPrimaryIndependent check
- Czeizel and Dudás: Prevention of first occurrence of neural-tube defects by periconceptional vitamin supplementationUS governmentPrimaryIndependent check
- Page et al.: Total folate and unmetabolized folic acid in Canadian breast milkUS governmentPrimaryIndependent check
- Yoo et al.: Folate and global health umbrella review series, part 1US governmentPrimaryIndependent check
- Shi et al.: Low maternal red blood cell 5-methyltetrahydrofolate levels and birth defectsUS governmentPrimaryIndependent check
Last reviewed 2026-10-16
Independent check 2026-10-16
Not yet clinician-reviewed
Ask your provider about your situation.