Neural Tube Defects and Folic Acid
The exact cause of neural tube defects is unknown. However, the causes of neural tube defects are thought to be a combination of environmental and genetic factors and a lack of folate in the diet - or the inability to naturally absorb folate.
Research to determine the causes of NTDs is still ongoing. What is evident though is that taking Folic Acid cannot prevent all occurrences of neural tube defects (including spina bifida) but it can help to reduce the risk by up to 75% when taken in the correct dosage and at the right time.
Not Planning Yet?
In Ireland 50% of all pregnancies are unplanned each year. Spina Bifida Hydrocephalus Ireland would recommend that any women of child bearing age take Folic Acid as part of their regular diet. Taking 400 micrograms / 0.4 mg of folic acid can reduce the risk of neural tube defects (NTDs) such as spina bifida. This dosage is present in some multivitamins, please check the label to confirm this with the brand you purchase.
It's a Small Effort
Folic acid is a B vitamin that can be found in some foods. It can be difficult to get your recommended daily allowance (RDA) of folic acid from food alone. Foods in which folate naturally occurs include baked beans, chick peas, green leafy vegetables, lentils, orange juice, oranges, peas, rice, soya beans, split peas, and sprouts. Vegetables should be lightly cooked or steamed as over-boiling destroys their vitamin content.
The most practical way to ensure you are getting enough folic acid in your diet is to take a folic acid supplement. If you take a multivitamin, check that it has the RDA of folic acid - 400 micrograms. To help prevent neural tube defects a daily vitamin supplement (tablet) of folic acid, before pregnancy (at least three months) and for the first 12 weeks of pregnancy.
What is the risk of having a baby with Spina Bifida?
Women who may become pregnant but who have not been identified as being in a high-risk group should also take folic acid. Folic acid should be taken for at least one month before conception and then until the end of the 12th week of pregnancy.
If a couple have already had a child with spina bifida (or have had a pregnancy affected by spina bifida) the risk of it happening in another pregnancy is about 1 in 35. For the general population the risk varies from 1 in 300 to 1 in 1000.
Women at higher risk of having a baby with an NTD should take a daily 5mg tablet of folic acid for at least one month before conception and then throughout the first 12 weeks of pregnancy. These 5mg tablets have to be obtained on prescription from a GP.
Women considered to be at higher risk of having a neural tube defect pregnancy include those who:
- have had a previously affected pregnancy
- have an NTD themselves (or their partner has an NTD)
- have a family history of NTD or whose partner has a family history of NTD
- have diabetes mellitus
- are very overweight
- have the ‘significant’ form of spina bifida occulta (see 'What is Spina Bifida Occulta?’)
Women in families where there has been spina bifida or another NTD in other relatives may wish to receive genetic counselling. In these cases, they should ask their doctor to refer them to a genetic counsellor.
More information about diet and vitamin supplementation can be obtained by contacting SBHI, GPs, health visitors, hospital doctors, dieticians, and pharmacists.
If you have any questions about this information please contact the SBHI helpline or e-mail: firstname.lastname@example.org