Folic Acid: Why is Folic Acid Important during Pregnancy?

When it comes to pregnancy there is a long list of do’s and don’ts. Unfortunately, it can be hard to differentiate between what is true and what is a myth. This brings us to the topic of folic acid – is it beneficial during pregnancy?

What is folic acid?

Folic acid is a synthetic form of folate – a naturally occurring vitamin in our body, also known as vitamin B9. Folate can be found in whole foods such as legumes, leafy greens, asparagus, avocado, sunflower seeds, okra, and black beans 1,2. On the other hand, folic acid is mainly found in supplements and fortified foods1. In 1998, Canada and the US implemented a mandatory program that adds folic acid to all wheat flour and corn products in order to increase the population`s folate intake3. The reason that folic acid is supplemented instead of folate is because its ability to be absorbed 70% higher in the body than the folate naturally found in food1.

Why is it important, especially in pregnancy?

In the human body, folate is needed to carry out many of the body`s functions. Some of these functions include cell division, the formation of new blood cells, cell growth, DNA replication, and tissue growth1,4. Since pregnancy is a time where rapid cell division is taking place, supplementation of folic acid is crucial. Although the exact mechanism is unknown4, fetal growth causes an increase in the total number of rapidly dividing cells, which leads to increased requirements for folate5. More specifically, folic acid is important in pregnancy because it promotes optimum growth of the neural tube (structure from which brain and spinal cord form). Therefore, an intake of folic acid reduces the risk of neural tube defects in the developing fetus1,2,3,4,5,6  . Neural tube defects (NTD) are abnormalities that arise because portions of the neural tube in the brain are not fully developed 1,3. NTD’s can have dramatic effects on an infant’s quality of life – not only does it affect the physical aspect, but it also affects an infant’s mental function4. NTD’s such as spina bifida can lead to leg weakness, paralysis, and other malformations4.  Taking folic acid during pregnancy is considered one of the most significant nutritional discoveries in the last 50 years3. Randomized control trials have shown that folic acid can reduce up to two thirds of neural tube defects4. After folic acid fortification in the US and Canada was introduced, follow up studies showed a 30% and 50% reduction in neural tube defects, respectively3.

How much folic acid should I take? 

Canadian survey data show that it is difficult for most women to consume enough folate from diet alone in order to meet their pregnancy needs2. Although folic acid is added to wheat flour and corn in Canada and the US, it is still not enough to produce an adequate amount of red blood cells to prevent NTD’s4.  To meet these needs, women should consume a diet high in folate and also take a folic acid supplement2. The recommended folic acid supplement in addition to one’s diet is 400μg/day or 0.4mg2,3,4,5 and should be taken 3 months prior to pregnancy6. Too much folic acid in the system is not always a good thing. Excess amounts of folic acid can actually mask the existence of a Vitamin B12 deficiency6. Therefore, one should not exceed more than 1 mg of folic acid per day unless directed by their physician.

I’m not pregnant, should I still take folic acid?

Yes, it is important for all women of child bearing age to take folic acid. Since most pregnancies are not planned, it is important to supplement folic acid in one’s diet. Women with unplanned pregnancies, mothers under the age of 25, and single mothers are less likely to take folic acid supplements2. Also, since the neural tube is formed in the first 28 days of pregnancy1, 3, a woman may not even be aware that she is pregnant for a majority of this time. Fortunately, folic acid can be found in most over the counter multivitamins. In addition, some medications such as antiepileptic medications lower folic acid levels in the body and as such folic acid supplementation becomes even more important in such cases in women and men.

I’m a man, can I still take folic acid?

Yes, folic acid is not only used for pregnancy. Folic acid can be used to treat conditions such as folate deficiency, anemia, depression, end-stage renal disease, age related macular regeneration, vitiligo, and many other medical conditions6. However, it is important to consult your doctor before taking folic acid supplements for any of these medical conditions.

I’m taking methotrexate, and my doctor prescribed folic acid as well. Why?

Methotrexate is a drug prescribed for rheumatoid arthritis and other medical conditions. A side effect of methotrexate is that it severely depletes the level of folic acid in the body6. This can lead to methotrexate toxicity and can cause side effects such as nausea and vomiting6. Folic acid has been shown to reduce these side effects6. Therefore, it is common for doctors to prescribe folic acid as a precaution and it is important to maintain a high folate diet while taking methotrexate.

Bottom line

Ultimately, folic acid is most important for use in women who are pregnant or wanting to become pregnant in order to prevent neural tube defects. The recommended dose is 400μg/day (0.4mg/day) in additional to normal dietary consumption of folate.  As with everything else, too much is never a good thing so make sure you consult with your health care professional if you may require a higher dose of folic acid.


Written By Sadia Haque

Edited and Reviewed by the Health Aisle Team


  1. De-Regil LM, Fernández-Gaxiola AC, Dowswell T, Peña-Rosas JP (2010). Effects and safety of periconceptional folate supplementation for preventing birth defects. Cochrane Database of Syst Rev, Oct 6;(10).
  2. Health Canada Prenatal Nutrition Guidelines for Health Professionals (2009).
  3. Jägerstad, M. (2012), Folic acid fortification prevents neural tube defects and may also reduce cancer risks. Acta Paediatrica,101:1007–1012.
  4. Roy A., Evers S. E., Campbell M. K (2012). Dietary supplement use and iron, zinc and folate intake in pregnant women in London,Ontario. Public Health Agency of Canada, 32(2).
  5. Lassi ZS, Salam RA, Haider BA, Bhutta ZA (2013). Folic acid supplementation during pregnancy for maternal health and pregnancy outcomes.  Cochrane Database of Syst Rev. Mar 28(3).  
  6. Folic Acid. Natural Medicines Comprehensive Database (2013)