Folic acid, healthy pregnancy and neural tube defect prevention

On this page

• About folic acid
• Importance of folic acid
• Proper folic acid dosage
• Risk factors for neural tube defects
• Benefits of a healthy diet

About folic acid

Folate is a B vitamin that is naturally found in certain foods. Folic acid is a form of folate added to fortified foods and supplements.

Learn more:

• Fortified foods

Importance of folic acid

Folate (folic acid) is important for the healthy growth of unborn babies. It helps reduce the risk of birth defects called neural tube defects.

The neural tube is the part of the developing baby that becomes the brain and spinal cord. Neural tube defects occur when the neural tube doesn’t fully close during the early weeks of pregnancy. This results in spine, brain and skull defects that can lead to stillbirth or lifelong disabilities.

The most common neural tube defects are:

• spina bifida (when the spine doesn’t close)
• anencephaly (when part of the brain and skull are missing)

When to take folic acid

Taking folic acid is important even if you’re not planning to become pregnant, as many pregnancies are unplanned. The benefits of taking folic acid to reduce neural tube defects are highest in the very early weeks of pregnancy. This timeframe is before most people know they’re pregnant.

If you’re planning to become pregnant and not taking folic acid, start taking it as soon as possible. It should be ideally started at least 3 months before pregnancy.

If you’re already pregnant and aren’t taking folic acid, start taking it as soon as possible. Continue taking folic acid throughout your pregnancy and while breastfeeding.

Proper folic acid dosage

A daily multivitamin with 400 mcg (0.4 mg) of folic acid is recommended for anyone who could become pregnant.

Dosage limits

A daily multivitamin with 400 mcg (0.4 mg) of folic acid is usually enough to reduce the risk of neural tube defects. However, some people need a higher dose. Talk to your health care provider about situations that need a higher daily dose of folic acid.

Do not take more than 1 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 talking to your health care provider.

Risk factors for neural tube defects

Family history

There are family history situations that may put you at a higher risk of having a baby with a neural tube defect. Possible situations might be if you or the biological parent:

• have a neural tube defect
• have a family history of neural tube defects
• had a previous pregnancy impacted by a neural tube defect
• have a family history of other folic acid-sensitive birth defects

Talk to your health care provider about your family history of neural tube defects and if you need a higher dose of folic acid.

Low folate levels

Medical conditions can impact the amount of folate in your body, including:

• obesity
• diabetes
• need for kidney dialysis
• bowel or gastrointestinal conditions like:
  • celiac disease
  • Crohn’s disease
  • gastric bypass surgery

Factors that can impact the amount of folate in your body include:

• how much folate you consume in your diet or if you take a folic acid supplement
• genetic factors that impact how your body processes and absorbs folate
• medical factors, such as if you:
  • take certain medications like an antiepileptic or other medications that block the body’s ability to use folate
  • smoke
  • have an alcohol or substance use disorder
• socioeconomic and cultural factors, such as if you’re experiencing poverty or a newcomer to Canada

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

Learn more:

• Social determinants of health and health inequalities

Benefits of a healthy diet

Eating nutritious foods is important to support overall nutritional health and well-being. Taking a vitamin supplement does not reduce or replace the importance of a healthy diet. Folate is found in a variety of foods, such as:

• corn
• oranges
• beans and lentils
• dark green vegetables like:
  • peas
  • spinach
  • broccoli
  • brussels sprouts

Foods fortified with folic acid can be sources of folate, including enriched:

• pasta
• cornmeal
• wheat flour

Dietary sources on their own are not enough to reach the required folate level to protect against neural tube defects. You still need to take a multivitamin with folic acid.

Learn more:

• Fortified foods
• Canada’s Food Guide: Healthy eating for teens
• Canada’s Food Guide: Healthy eating for adults
• Canada’s Food Guide: Healthy eating when pregnant and breastfeeding

Related links

• Your Guide to a Healthy Pregnancy
• Before you conceive: Folic acid (The Society of Obstetricians and Gynaecologists of Canada)

For health care providers and policy makers

• Canada’s Food Guide: Advice on vitamin and mineral supplementation
• Canada’s Food Guide: Nutrition considerations during pregnancy and to support breastfeeding
• Society of Obstetricians and Gynaecologists of Canada Clinical Practice Guideline: Folic acid and multivitamin supplementation for prevention of folic acid–sensitive congenital anomalies (Journal of Obstetrics and Gynaecology Canada, 2022)