Why do I need folic acid in pregnancy?

Folic acid (also known as vitamin B9) is very important for the development of a healthy foetus, as it can significantly reduce the risk of neural tube defects (NTDs), such as spina bifida.

Sources of folic acid

The Department of Health recommends that women should take a daily supplement of 400 micrograms of folic acid while they are trying to conceive, and should continue taking this dose for the first 12 weeks of pregnancy, when the baby's spine is developing. However, it is safe to continue taking folic acid supplements after 12 weeks.

If you didn’t take folic acid supplements before getting pregnant, you should start taking them as soon as you find out you’re pregnant.

You can get folic acid tablets from pharmacies, large supermarkets, health food stores or on prescription from your GP. One daily tablet contains exactly the amount of folic acid that you need.

Dietary sources of folic acid include green, leafy vegetables, brown rice, granary bread and breakfast cereals fortified with folic acid. Always check the food labels. However, it would be almost impossible to get enough folic acid just from food; the only way to be sure you are getting the right amount is by taking a supplement.

Liver is also very rich in folic acid, although it is not safe to eat while you are pregnant, or trying to become pregnant. This is because liver is also very rich in vitamin A, too much of which can cause birth defects in your baby.

Folic acid for those at higher risk of NTDs

Some women have an increased risk of having a pregnancy affected by a neural tube defect, and are advised to take a higher dose of 5 milligrams (5mg) of folic acid each day until they are 12 weeks pregnant. You have an increased risk if:

  • you or your partner have a neural tube defect 
  • you have had a previous pregnancy affected by a neural tube defect
  • you or your partner have a family history of neural tube defects
  • you have diabetes

In addition, you should consult your GP for advice if you’re taking anti-epileptic medication, as you may also need to take a higher dose of folic acid.

If any of the above applies to you, talk to your GP as they can prescribe a higher dose of folic acid. Your GP or midwife may also recommend additional screening tests during your pregnancy.

Further information:

Page last reviewed: 27/03/2013

Next review due: 26/03/2015