If you could become pregnant, learning about folate and folic acid includes considering a daily folic acid supplement before you know whether you are pregnant. Neural tube development happens very early, so starting before conception helps ensure folic acid is available during this key period. In many places, the usual dose is 400 micrograms (mcg) a day; some people may be advised to take a higher dose under medical guidance.
Folate and folic acid: What’s the difference?
Folate is vitamin B9 in its natural forms in foods such as leafy greens, beans, citrus fruit and whole grains. Folic acid is a stable, manufactured form used in most supplements and in fortified foods. Both contribute to the body’s folate supply, but they are not identical forms of the vitamin.
Food folate is valuable, but eating folate-rich foods is not a substitute for the recommended supplement before pregnancy. Folic acid is the form specifically recommended for reducing the risk of neural tube defects (NTDs), including spina bifida. Fortified foods may add to your intake, but the amount you get depends on where you live and what you eat.
When to start folic acid and how long to continue
Start at least one month before trying to conceive if you can. Continue through the first 12 weeks of pregnancy, when the neural tube forms and closes. Because this happens before many people know they are pregnant, waiting for a positive test can mean missing part of the recommended window. If you are already pregnant and have not been taking folic acid, start by contacting your clinician or following your local pregnancy guidance; there is still value in getting advice promptly.
Recommendations after the first trimester differ. Some guidance focuses on the first 12 weeks for NTD prevention, while other guidance recommends a low daily dose throughout pregnancy or breastfeeding. Follow the advice where you live, and check whether your prenatal vitamin already contains folic acid before adding another supplement.
Usual doses, higher doses and regional differences
For most people, common guidance in the United States, United Kingdom and Australia is 400 mcg daily before conception and in early pregnancy. Many European countries also recommend a 400 mcg supplement, but advice and fortification rules are set nationally, so there is no single dose or policy that applies across the whole EU.
Fortification also affects what is in your food supply. The US requires folic acid in enriched cereal grains, while Australia requires it in bread-making flour. EU policies vary by country. UK wheat-flour fortification rules have been changing, so don’t assume that foods provide the same amount of folic acid in every market. Fortification can increase population intake, but it does not remove the need to check your local supplement recommendation.
Higher-dose guidance varies: the US may recommend 4 milligrams (mg) for someone with a previous NTD-affected pregnancy, while UK and Australian guidance commonly uses 5 mg for people assessed as being at higher risk. EU recommendations depend on the country. Do not try to reach a high dose by taking several prenatal multivitamins, which can also raise your intake of other nutrients.
The reason for higher-dose recommendations includes findings from the UK Medical Research Council Vitamin Study. This multicentre trial studied women planning another pregnancy after a previous NTD-affected pregnancy. The researchers found that 4 mg of folic acid, started before conception and continued through the first three months, reduced recurrence by about 70%. This result applies to recurrence prevention in that higher-risk group; it does not mean everyone should take 4 mg.
A previous NTD-affected pregnancy is an important reason to seek preconception advice. Some health conditions or medicines may also affect the recommended dose. Ask a clinician or pharmacist to check your situation and the label on any prenatal vitamin before taking more than the standard amount. For a broader look at another nutrient to check in a prenatal product, see what to know about choline in pregnancy.