Early in pregnancy, when the foetus is developing, folic acid plays an important role in the development of the neural tube. As the foetus grows, the neural tube develops into the brain and spinal cord.
Sometimes an abnormality occurs when the neural tube does not close properly. This causes conditions known as neural tube defects (NTDs).
- Neural tube defects happen in about 1 in 500 babies.
- Some examples of neural tube defects are spina bifida, where the spine or its covering sticks out of the back, and anencephaly, in which the brain doesn't form properly.
- Babies born with these defects often die, or have problems with walking and bowel and bladder control.
Research shows that women who have a high level of folic acid before they become pregnant are less likely to give birth to a baby with a neural tube defect. Folic acid supplementation can prevent up to 70% of these defects.
Image credit: Canva
Amount of folic acid to take during pregnancy
During your pregnancy, you should eat plenty of foods with folate in them, such as leafy green vegetables, wholegrain breads and cereals. However, you will not get enough folate from food to prevent NTDs.
|The only way to be sure you're getting the right amount of folic acid during pregnancy is by taking a supplement.
In Aotearoa New Zealand, there are 2 funded strengths of folic acid tablets:
- 800 microgram
- 5 milligram.
Some dietary supplements and multivitamins have small amounts of folic acid, but it may not be enough for you.
- For women who do not have high risk factors – the usual dose of folic acid for the prevention of NTDs is 800 micrograms once a day. Read more about folic acid tablets.
- High-risk pregnancies – some women are at increased risk of having a baby with a spinal cord problem. These women need higher doses of folic acid, 5 milligrams once a day.
You are at higher risk if:
- you have had a previous pregnancy affected by a neural tube defect
- you or your partner have a spinal cord defect
- your or your partner have family members with a spinal cord defect
- you are taking medication that is known to affect folate metabolism, such as medicine for epilepsy (eg, carbamazepine, sodium valproate)
- you are on insulin treatment for diabetes
- you are very overweight, that is, if your body mass index (BMI) is 30 or more
- you have coeliac disease, diabetes, sickle cell anaemia or thalassaemia.
If you are planning to get pregnant, be sure to get enough folate to reduce the risk of these serious conditions for your baby.
When to start taking folic acid
If you are planning a pregnancy or are pregnant, the Ministry of Health(external link) advice for most women is to take one 800 micrograms (mcg) folic acid tablet daily for at least 4 weeks before getting pregnant and to continue taking the tablet daily until the end of week 12 of your pregnancy. If you find you are pregnant during the first 12 weeks of pregnancy, you should take the tablet from that point until the end of week 12.
If you find out you are pregnant and haven’t been taking a folic acid tablet, start taking tablets straight away.