What is the Most Important Supplement for a Healthy Pregnancy? Folate. Here’s Why

Pregnancy folic acid

Women who are pregnant or who are planning to become pregnant are advised to start taking prenatal vitamins (or supplements) as early as possible. The most important of all the prenatal vitamins is folic acid,  or folate (vitamin B9).  Unfortunately, it is difficult to get enough folate through diet alone and so adding a folate supplement is recommended.

Why is folic acid important?
There is no question that taking folate supplements prevents birth defects.  These include brain defects like anencephaly (when  parts of a baby’s brain and skull do not develop), neural tube defects like spina bifida (when the neural tube encasing the spinal nerves does not develop completely), heart defects, and oral facial clefts (cleft lip and palate).Anencephaly is almost always fatal and spina bifida causes physical and learning problems which range from mild to severe.5,6

As well as preventing birth defects, folate supplementation can also help to prevent anemia (low iron levels in your blood) and preterm birth.Supplementation for at least one year before conception has been associated with fewer babies born at both 20-28 weeks and 28-32 weeks, compared with no folic acid supplementation.7

Other potential benefits from taking folate supplements around the time of conception and through pregnancy are better placental development, reduced risk of fetal growth restriction and fetal death, lower risk of high blood pressure, and lower risk of the placenta being separated from the wall of the womb.6,8

Therefore, there are many reasons to make sure you are getting enough folate, even when a planned pregnancy is many months away. Folate is the most important vitamin supplement for a healthy pregnancy.

What is the difference between folic acid/folate/L-methylfolate?
Foods that are rich in naturally occurring folate include lentils, dried beans and peas, dark green vegetables such as broccoli, spinach, collard or turnip greens, okra, and asparagus, and citrus fruit and juice. Folic acid is a synthetic or man-made form of folate, which is more easily absorbed in the body than the folate in food. L-methylfolate is a newer synthetic form of folate, which is even easier to absorb. Quite a few women are not able absorb folic acid properly and, therefore, should take the L-methylfolate form. A MTHFR test can be ordered by your health care provider to determine if you are one of these women. The L-methylfolate form should also be taken by women who have a personal or family history of babies with defects in their spinal cord or brain (such as spina bifida or ancephaly) or babies who are born prematurely (less than 37 weeks).

The L-methyfolate form might also be suitable for pregnant women without this history as it has been found to increase levels of hemoglobin in the second trimester. The hemoglobin  in red blood cells is what carries oxygen around the body and helps to get rid of carbon dioxide. Therefore,  women who take L-methyfolate form of vitamin B9  have a lower risk of anemia (low hemoglobin levels) in the months following pregnancy, compared to women who take the folic acid form.

Both folic acid and L-methylfolate are available over-the-counter individually and in different brands of prenatal vitamins. If you are planning on becoming pregnant, or are already pregnant, it would be worth discussing with your health care provider which form of folate you should take.1,3,4


  1. ncbi.nlm.nih.gov/pmc/articles/PMC3250974
  2. http://womenshealth.gov/publications/our-publications/fact-sheet/folic-acid.html
  3. ncbi.nlm.nih.gov/pmc/articles/PMC3218540/
  4. ncbi.nlm.nih.gov/pubmed/21440300/
  5. cdc.gov/ncbddd/spinabifida/facts.html
  6. ncbi.nlm.nih.gov/pubmed/19434228/
  7. ncbi.nlm.nih.gov/pmc/articles/PMC2671168/
  8. ncbi.nlm.nih.gov/pubmed/10452905/
Melody Watson
Melody Watson holds Bachelors degrees in Biochemistry and Microbiology. She works as a medical writer for a medical communications agency in Berlin, Germany, where her work ranges from medical translation to writing publications for medical journals. Melody is passionate about promoting science, including evidence-based medicine, and debunking pseudoscience.

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