Low Folic Acid Levels and Miscarriage Risk

Can Supplementing Folic Acid Prevent Pregnancy Loss?

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You've probably heard that your should take folic acid before and during pregnancy to prevent neural tube defects, but you may be wondering if too little of the vitamin can also affect your miscarriage risk. The jury is out on whether too little folic acid contributes to miscarriages, or if supplementing can help prevent them. On the flip side, it does not appear that folic acid supplementation increases the risk of miscarriages.

Understanding the Recommendations

Doctors advise that women of reproductive age should get at least 400 micrograms of folic acid every day. Folic acid is the synthetic form of folate - a nutrient in the B vitamin group - that is used in supplements and fortified foods.

A lot of research is being done on the impact of folate on various areas of health. It has long been accepted that being deficient in folic acid means a woman will have a higher risk of giving birth to a baby with neural tube defects - birth defects involving the brain and spinal cord. This is why in many countries, including the U.S., grain products are fortified with folic acid. Research shows that this fortification has led to a decrease in the incidence of neural tube defects.

Severe neural tube defects, such as anencephaly, may be incompatible with life and thus can result in late pregnancy loss.

Folic Acid and Miscarriages

You may have heard about the importance of getting adequate folic acid because it reduces the risk of neural tube defects.

But is folic acid important in pregnancy for other reasons, too?

Do low folic acid levels cause miscarriage? A few studies have suggested that being deficient in folic acid is associated with higher risk of early miscarriage. One 2002 study by Swedish researchers found that women with low folate levels had a significantly increased risk of having a miscarriage affected by chromosomal abnormalities.

Not all studies, however, show this association. Bottom line: The research is not yet strong enough to state that folic acid can prevent miscarriages.

Does taking folic acid cause miscarriage? Researchers on early studies claimed to show this association, but there was a major flaw in the research: Women in those studies took multivitamins - not just folic acid. More recent research - including the 2002 Swedish study - strongly suggests that folic acid supplementation does not increase the risk of miscarriage. A large study of almost 24,000 Chinese women published in 2001 also found no link between supplementation and miscarriage risk. Bottom line: Folic acid supplementation does no appear to increase the risk of miscarriages.

How to Get Enough Folic Acid and Folate

Regardless of whether folic acid helps prevent miscarriages, you need to get enough of it to prevent birth defects.

Folic acid supplements, multivitamins and and prenatal vitamins usually contain the recommended minimum amount of folic acid (at least 400 micrograms).

Women of childbearing age should take adequate folic acid and get folate from food. Good food sources include fortified breakfast cereals, leafy green vegetables, nuts, beans, peas, dairy, fruits and fruit juices, poultry, meat, eggs, seafood and grains. A few foods that are particularly rich in folate are spinach, liver, yeast, asparagus and Brussels sprouts.


Folic Acid Recommendations. Centers for Disease Control and Prevention. April 28, 2015.

Folate: Dietary Supplement Fact Sheet. Office of Dietary Supplements, National Institutes of Health. December 14, 2012.

George, L., Mills, J.L, Johansson, A.L.V., et al. (2002). Plasma Folate Levels and Risk of Spontaneous Abortion. JAMA.

Gindler, J., Li, Z., Berry, R.J., et al. (2001). Folic acid supplements during pregnancy and risk of miscarriage. The Lancet.

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