Here’s another reason for pregnant women to take folic acid supplements: they help prevent fetal heart malformations, new research from the Netherlands suggests.

“Given the relatively high prevalence of congenital heart defects worldwide, our findings are important for public health,” Dr. Ingrid M. van Beynum of Radboud University in Nijmegen and her colleagues write.

Folic acid supplements are now recommended for all pregnant women, and women planning on becoming pregnant, in order to prevent birth defects involving the neural tube such as spina bifida. Many countries, including the US, now require bread and other wheat products to be fortified with folic acid for this reason, but this practice hasn’t been adopted in The Netherlands.

While there’s been some evidence that folic acid may help prevent heart-related birth defects too, van Beynum and her team write, “this has not yet been definitively established.” Such defects are quite common, they note, occurring in up to 2 out of every 100 newborns worldwide.

To investigate further, the researchers used a national register of birth defects to identify 611 mothers who had given birth to a child with a heart defect, matching them to 2,401 women who delivered babies with genetic defects or other birth defects unrelated to folate.

Women who took a supplement containing at least 400 micrograms of folic acid were nearly 20 percent less likely to have a child with a heart defect, compared to other non-folate-related malformations, while their risk compared to the general population was 26 percent lower.

Their risk of having a child with a heart defect involving the septum - which separates one side of the heart from the other - was nearly 40 percent lower than that of the general population.

The current study couldn’t show whether taking more or less than 400 micrograms of folic acid would be more effective in preventing heart defects, the researchers note, although there’s increasing evidence that heavier women may need to take more folic acid to get the same protective effects.

The researchers conclude that women who want to become pregnant should take folic acid supplements around the time of conception, not only to prevent neural tube defects but also to reduce the risk of congenital heart defects.

SOURCE: European Heart Journal December 1, 2009.