Folic acid linked to spontaneous abortions

By Robert A. Hatcher, MD, MPH

Professor of Gynecology and Obstetrics

Emory University School of Medicine


Not one of us likes abortions. In general, we would definitely rather see women avoid unintended pregnancies than to be faced with the ever-difficult dilemma of deciding what to do about an unintended or unwanted pregnancy. But now we learn that there is an approach to bearing a healthy child that both causes abortions and leads to a healthy child. It appears that taking folic acid supplementation to prevent neural tube defects, a widely accepted recommendation accepted in virtually all public health circles, causes an increased risk of spontaneous abortions.

In fact, calculations of the number of malformations prevented and the number of abortions triggered match quite well. This suggests that folic acid may protect against birth defects by inducing abortions in malformed fetuses. This is the conclusion of Ernest B. Hook, MD, speaking at the annual meeting of the Bethesda, MD-based American Society of Human Genetics. Hook is a professor in the School of Public Health at the University of California, Berkeley.

"Society, apparently, pays the unrecognized price of increased abortions for an agent that prevents malformations," he said.1

Consider findings of studies

Curiously, folic acid increases the fertility rate of women by 3.4% and the live birth rate by 1.7%, which is paradoxical for an agent that causes spontaneous abortions. Data from Hungary demonstrate that the spontaneous abortion rate was 16% higher in nearly 2,800 women taking folic acid compared with the more than 2,600 women who did not take folic acid supplementation.2 The difference was statistically significant.

Hook also looked at data from England and found that there was a 15% increase in the rate of spontaneous abortions among more than 900 women who took folic acid supplementation compared with women who did not take folic acid supplements.

In summary, Hook calculates that for every 1,000 women who take folic acid supplementation, there are eight fewer malformed infants and 18 more abortions. Hook concluded that "the relative risk of abortion can numerically account for the entire protective effect."

These data raise all sorts of questions. I certainly wonder just how those unalterably opposed to abortion will respond. Will we have to provide informed consent to women receiving folic acid? Will the federal government continue to actively encourage folic acid supplementation through public health initiatives? Will the data cause some of those now opposed to abortion under all circumstances to adopt a pro-choice position?


1. Zoler M. Folic acid increases spontaneous abortions. OB GYN News 1996; Dec. 15:1-2.

2. Dudaeas I, Rockenbauer M, Czeizel AE. The effect of preconceptual multivitamin supplementation on the menstrual cycle. Arch Gynecol Obstet 1995; 256:115-23.