Low Folic Acid Levels Linked with Increased Risk of Early Spontaneous Abortion

Women with low folic acid levels are at a significantly increased risk of having an early, naturally occurring termination of their pregnancy, according to an article in the October 16 issue of The Journal of the American Medical Association (JAMA).

According to background information in the article, both folate deficiency and folic acid supplements have been reported to increase the risk of spontaneous abortion, which refers to the naturally occurring termination of a pregnancy – end of the pregnancy with expulsion of the fetus from the woman`s body — before the 20th week of pregnancy. The authors write that the results of previous studies are inconclusive, and measurements of folate have not been available in all studies.

Lena George, M.D., of the Huddinge University Hospital, Karolinska Institutet, Stockholm, Sweden, and and colleagues conducted a study to determine the association between plasma folate levels and the risk of spontaneous abortion. The study was conducted between January 1996 to December 1998 in Sweden, where folic acid food fortification has not been introduced. The research included 468 women who had a spontaneous abortion, and 921 controls. Plasma folate measurements were taken at 6 to 12 gestational weeks.

The authors found that compared with women with plasma folate levels between 2.20 and 3.95 nanograms (ng)/milliliter (mL), women with low (equal or less than 2.19 ng/mL) folate levels were at nearly a 50 percent increased risk of having a spontaneous abortion. Women with higher folate levels (3.96-6.16 ng/mL and equal to or greater than 6.17 ng/mL) showed no increased risk of spontaneous abortion.

The authors write that no mechanism by which low folate levels could cause spontaneous abortion has yet been identified.

“Our results have important public health and clinical implications. High folate status, as increasingly seen in the United States and many other Western countries because of food fortification and supplement use, is not associated with an increased risk of spontaneous abortion, whereas low folate levels are associated with an increased risk of spontaneous abortion. Countries that have fortified their food supplies with folic acid and those considering doing so can be reassured that fortification most likely will not increase spontaneous abortion rates and might even decrease them,” the authors conclude.