The NHS recommends 400 micrograms of folic acid daily from before conception until at least week 12 of pregnancy. Folic acid reduces the risk of neural tube defects such as spina bifida by up to 70%. Some people need a higher dose of 5mg daily. Good food sources include leafy greens, fortified cereals, chickpeas, and oranges, but supplements are still recommended as it is difficult to get enough from diet alone.
Folic acid is the synthetic form of folate (vitamin B9). It plays a critical role in the earliest stages of pregnancy by helping to form the neural tube, which becomes the baby''s brain and spinal cord. The neural tube closes within the first 28 days after conception, often before you even know you are pregnant. This is why taking folic acid before and during early pregnancy is so important.
Research has consistently shown that folic acid supplementation reduces the risk of neural tube defects (NTDs) such as spina bifida and anencephaly. A landmark Medical Research Council study found that folic acid reduced the recurrence of NTDs by 72%. Based on this evidence, the NHS, NICE, and WHO all recommend folic acid supplementation for all people planning a pregnancy.
Standard dose: 400 micrograms (0.4mg) daily. This is the recommended dose for most people. It should be taken as a supplement from the time you start trying to conceive (or as soon as you find out you are pregnant) until at least the end of week 12.
Higher dose: 5 milligrams (5mg) daily. NICE recommends the higher dose if you have had a previous pregnancy affected by a neural tube defect, you or your partner have a neural tube defect or family history of one, you have diabetes (type 1 or type 2), you take anti-epileptic medication, you have coeliac disease or other malabsorption conditions, you have sickle cell disease or thalassaemia, or your BMI is 30 or above.
The 5mg dose requires a prescription from your GP. Speak to your doctor before your booking appointment if you think you may need it.
Ideally, start at least one month before conception. Because the neural tube forms so early, having adequate folate levels before conception gives the best protection. If your pregnancy was unplanned, start taking folic acid as soon as you find out you are pregnant.
Continue until at least week 12. By this point, the neural tube has fully closed. After 12 weeks, continuing folic acid is not harmful, and many pregnancy multivitamins include it throughout. Some people choose to continue for the full pregnancy as folate supports cell growth and red blood cell production.
While supplements are recommended because it is difficult to get enough from food alone, including folate-rich foods in your diet is beneficial. Good sources include dark leafy greens such as spinach, kale, and broccoli, fortified breakfast cereals (check the label for folic acid), chickpeas, kidney beans, and lentils, oranges and orange juice, beetroot, asparagus, and Brussels sprouts.
Be aware that folate is water-soluble and heat-sensitive. Steaming vegetables rather than boiling them helps preserve their folate content.
Folic acid supplements are available from pharmacies, supermarkets, and online. Look for supplements that provide 400 micrograms of folic acid. You do not need an expensive brand — the supermarket own-brand versions contain the same active ingredient.
Many people prefer a combined pregnancy multivitamin that includes folic acid alongside vitamin D, iron, and other nutrients. This is fine, but check that it does not contain vitamin A (retinol), which should be avoided in pregnancy.
If you are eligible for Healthy Start, you can get free vitamins that include folic acid. Your midwife can help you apply at your booking appointment.
If you did not take folic acid before conception, do not panic. Start taking it as soon as you find out you are pregnant. Many pregnancies are unplanned, and the risk of neural tube defects is still relatively low overall. The supplement reduces an already small risk further.
Neural tube defects occur in approximately 1 in 1,000 pregnancies in the UK. Folic acid supplementation reduces this risk by up to 70%. Even if you start late, you are still providing protection during the critical period of neural tube closure.
In 2024, the UK government confirmed that folic acid will be added to non-wholemeal wheat flour, following countries like the US, Canada, and Australia which have fortified flour for decades. This mandatory fortification is expected to prevent an estimated 200 neural tube defect-affected pregnancies per year in the UK. However, fortification is designed as a population-level measure and does not replace the recommendation for individual supplementation before and during pregnancy.
Ideally at least one month before trying to conceive. If your pregnancy was unplanned, start as soon as you find out. The critical window is the first 12 weeks when the neural tube forms.
400 micrograms (0.4mg) daily for most people. If you have risk factors such as a previous NTD-affected pregnancy, diabetes, or BMI over 30, your GP may prescribe a higher dose of 5mg.
The standard 400 microgram dose is safe. Very high doses (above 1mg without medical supervision) are not recommended as they may mask symptoms of vitamin B12 deficiency. Always follow your GP or midwife advice.
Folic acid is specifically recommended to prevent neural tube defects, not miscarriage. However, adequate folate levels support healthy cell division and may contribute to overall pregnancy health.
It is very difficult to get the recommended amount from food alone, which is why the NHS recommends a supplement. Food sources of folate are still valuable but should not replace supplementation.
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