Folic Acid in Pregnancy: How Much and When to Start

The NHS recommends taking 400 micrograms of folic acid every day for the first 12 weeks of pregnancy ¹. The Office on Women's Health says all women who can get pregnant should take 400 to 800 micrograms every day, even if they are not planning to get pregnant ². The NHS says to start ideally 3 months before conception ¹.

Key takeaways

• The NHS recommends a 400 microgram folic acid supplement every day for the first 12 weeks of pregnancy ¹.
• The Office on Women's Health says all women who can get pregnant should take 400 to 800 micrograms of folic acid every day, even if they are not planning to get pregnant ².
• The NHS says taking folic acid in early pregnancy reduces the chance of the baby having a neural tube defect such as spina bifida ¹.
• The Office on Women's Health says birth defects of the brain and spine can happen in the first few weeks of pregnancy, often before a woman knows she is pregnant ².
• The NHS says not to take cod liver oil or supplements containing vitamin A, sometimes called retinol, because too much vitamin A can harm your baby's development ¹.
• The Office on Women's Health says you should not get more than 1,000 micrograms of folic acid a day, unless your doctor prescribes a higher amount ².

**A quick, honest note:** we're not medical professionals - everything here was researched by us from the public sources listed at the bottom of this page, and it isn't professional advice. Read our full note ↓

How much folic acid should I take in pregnancy?

For folic acid in pregnancy, the NHS recommends taking a 400 microgram supplement every day for the first 12 weeks ¹. The Office on Women's Health says all women who can get pregnant should take 400 to 800 micrograms of folic acid every day, even if they are not planning to get pregnant ². The Centers for Disease Control and Prevention says all women capable of becoming pregnant should get 400 mcg of folic acid every day ³. MedlinePlus says experts recommend women who can or plan to become pregnant take at least 400 micrograms of folic acid every day, even if they are not expecting to become pregnant ⁴. The Office on Women's Health says, "Folic acid is the man-made form of folate, a B vitamin" ². The Office on Women's Health also sets an upper limit, saying you should not get more than 1,000 micrograms of folic acid a day, unless your doctor prescribes a higher amount ².

When should I start taking folic acid?

On timing, the NHS says folic acid is recommended when you are trying to conceive, ideally 3 months before, or as soon as you find out you are pregnant ¹. The NHS says taking folic acid in early pregnancy reduces the chance of the baby having a neural tube defect such as spina bifida ¹. The Office on Women's Health says these birth defects can happen in the first few weeks of pregnancy, often before a woman knows she is pregnant ². The NHS recommends taking it every day for the first 12 weeks of pregnancy ¹. The Centers for Disease Control and Prevention says neural tube defects are major birth defects of the baby's brain, such as anencephaly, and spine, such as spina bifida ³. MedlinePlus says taking folic acid before and during pregnancy can reduce the risk for certain birth defects, and that "These include spina bifida, anencephaly, and some heart defects" ⁴.

What supplements should I avoid in pregnancy?

When it comes to what to avoid, the NHS says not to take cod liver oil or supplements containing vitamin A, sometimes called retinol, when you are pregnant, because too much vitamin A can harm your baby's development ¹. On folic acid itself, the Office on Women's Health also says, "You should not get more than 1,000 micrograms of folic acid a day, unless your doctor prescribes a higher amount" ².

Who needs a higher dose of folic acid?

Below is what the NHS and MedlinePlus say about who may need a higher dose of folic acid. The NHS says a higher dose of 5 milligrams of folic acid every day, which can be prescribed by a GP, is recommended for some women at higher risk who are planning a pregnancy or are less than 12 weeks pregnant ¹. MedlinePlus says women with a history of delivering a baby with a neural tube defect may need a higher dose of folic acid, and that a woman who has had a baby with a neural tube defect is advised to take 5 mg of folic acid every day, even when not planning to become pregnant ⁴.

Frequently asked questions

How much folic acid should I take in pregnancy?

The NHS recommends 400 micrograms of folic acid every day for the first 12 weeks of pregnancy ¹. The Office on Women's Health says all women who can get pregnant should take 400 to 800 micrograms every day, even if they are not planning to get pregnant ².

When should I start taking folic acid?

The NHS says to start when you are trying to conceive, ideally 3 months before, or as soon as you find out you are pregnant ¹. The Office on Women's Health says birth defects of the brain and spine can happen in the first few weeks of pregnancy, often before a woman knows she is pregnant ².

What supplements should I avoid in pregnancy?

The NHS says not to take cod liver oil or supplements containing vitamin A, sometimes called retinol, because too much vitamin A can harm your baby's development ¹. The Office on Women's Health says you should not get more than 1,000 micrograms of folic acid a day, unless your doctor prescribes a higher amount ².

Who needs a higher dose of folic acid?

The NHS says a higher 5 milligram dose, which can be prescribed by a GP, is recommended for some women at higher risk who are planning a pregnancy or are less than 12 weeks pregnant ¹. MedlinePlus says a woman who has had a baby with a neural tube defect is advised to take 5 mg of folic acid every day, even when not planning to become pregnant ⁴.

A note from us

We're the team behind Yael & Michal. We are not doctors, nurses, lactation consultants, or psychologists, and nothing here is professional advice.

Everything above was researched by us from public, reputable sources - we name and link every one of them below - and summarized as carefully as we could, as a free resource for other mothers. We do this because we wished something like it had existed for us.

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We try hard to get it right, and we cite our sources so you can check us. But we are not a medical authority, and this cannot replace talking to a professional who knows you and your baby. Please check anything that matters with your doctor, midwife, or an IBCLC lactation consultant. This content has not been reviewed by a medical professional. Reading this site does not create a doctor-patient relationship, or any other professional relationship, between you and us.

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Sources

1. NHS (National Health Service, UK). https://www.nhs.uk/pregnancy/keeping-well/pregnancy-vitamins-and-supplements/ (retrieved 2026-07-10).
2. Office on Women's Health (U.S. Department of Health and Human Services). https://womenshealth.gov/a-z-topics/folic-acid (retrieved 2026-07-10).
3. CDC (Centers for Disease Control and Prevention). https://www.cdc.gov/folic-acid/about/index.html (retrieved 2026-07-10).
4. MedlinePlus (U.S. National Library of Medicine). https://medlineplus.gov/ency/article/002092.htm (retrieved 2026-07-10).