Folic acid and neural tube defects

Folic acid, or folate, is one of the B vitamins important for the healthy growth of your unborn baby. It helps reduce the risk of your baby being born with neural tube defects (NTDs).

On this page:

• Why you need to take folic acid
• About neural tube defects
• Proper folic acid dosage
• Why you may need a higher dose
• Dosage limits for folic acid
• Benefits of a healthy diet

Why you need to take folic acid

Folic acid is vital to the normal growth of your baby's spine, brain and skull. Taking a daily vitamin supplement that has folic acid can reduce the risk of your baby having a neural tube defect.

The benefits of taking folic acid to reduce the risk of NTDs are highest in the very early weeks of pregnancy. At this stage, most women do not know they are pregnant. For this reason, taking folic acid before you become pregnant and in the early weeks of pregnancy is very important.

It’s never too early to ask your health care provider about folic acid.

About neural tube defects

The neural tube is the part of the developing baby that becomes the brain and spinal cord. NTDs occur when the neural tube does not fully close during the early weeks of pregnancy.

This results in spine, brain and skull defects that can lead to stillbirth or lifelong disability. Spina bifida (when the spine does not close) and anencephaly (when part of the brain and skull are missing) are the most common NTDs.

Proper folic acid dosage

All women who could become pregnant need to take a multivitamin with 0.4 mg of folic acid in it every day. Even if you are not planning to become pregnant, you need to take folic acid because many pregnancies are unplanned.

If you are planning to become pregnant, take the supplement for at least three months before pregnancy.

If you are already pregnant and not taking folic acid, start taking it as soon as possible. During your pregnancy, keep taking your daily folic acid supplement.

Why you may need a higher dose

Some women may need a higher dose of folic acid. This can include women with:

• a previous pregnancy affected with NTD
• a family history of other folic acid-related birth defects
• a family history  of NTD (or a male partner with a family history of NTD)

Women with certain medical conditions and on certain drugs may also need a higher dose of folic acid. These conditions and drugs may include:

• celiac disease
• kidney dialysis
• alcohol overuse
• advanced liver disease
• gastric bypass surgery
• inflammatory bowel disease
• pre-pregnancy diabetes (type 1 or 2)
• antiepileptic or other folate inhibiting drugs

Talk to your health care provider to see if you require a higher dose of folic acid.

Dosage limits for folic acid

Do not take more than one daily dose of your supplement as described on the product label. You should not increase your dose of folic acid beyond 1 mg per day without a health care provider’s advice.

Benefits of a healthy diet

Taking a vitamin supplement does not reduce or replace the need for a healthy, well-balanced diet. Some great sources of folate include:

• corn
• beans and lentils
• dark green vegetables
  • peas
  • spinach
  • broccoli
  • Brussels sprouts
• oranges

Foods fortified with folic acid are also great sources of folate. These foods include:

• white flour
• ready-to-eat cereals
• enriched pasta and cornmeal

However, dietary sources on their own are not enough to reach the required folate level to protect against NTDs. You still need to take a multivitamin with folic acid.

For more information

• The Society of Obstetricians and Gynaecologists of Canada – Pregnancy Info: folic acid

For health care providers

• Nutrition considerations during pregnancy and to support breastfeeding
• Public Health Agency of Canada - Folic acid use among pregnant women in Canada (2014)
• SOGC Clinical Practice Guideline - Pre-conception folic acid and Multivitamin Supplementation for the Primary and Secondary Prevention of Neural Tube Defects and Other folic acid-Sensitive Congenital Anomalies (2015)