A new study suggests that women who take daily folate supplements before and during pregnancy may reduce the chances of their babies developing not only neural tube defects, such as spina bifida, but also Down syndrome.

The study, published in the British journal The Lancet, shows that insufficient folate levels in women aged 15 to 45 can play a role in their babies developing Down syndrome or neural tube defects.

“Totally by accident, about 15 years ago it was discovered that if folate was taken by pregnant women shortly before conception, it could reduce the risk of neural tube defects,” says Dr. Paul Munk, a pediatrician in private practice in Toronto.

Now researchers from Ukraine, Israel and England have found a link between Down syndrome and neural tube defects. They've discovered that mothers at high risk for having babies with Down syndrome (because of a previous pregnancy that resulted in a baby with this condition) are more than three times as likely as other mothers of the same age to have babies with neural tube defects. The researchers also found that mothers at high risk for having babies with neural tube defects (because of a previous pregnancy that resulted in this defect) are more than five times as likely as mothers of the same age to give birth to babies with Down syndrome.

According to the study's authors, the problem could lie in some women's inability to properly break down and use folate. “Although it's not clear how,” says Munk, “folate plays a role in cell division.” Insufficient levels of folate seem to cause problems when chromosomes separate before conception. A chromosomal abnormality on the 21st chromosome results in Down syndrome.

Munk strongly recommends that women take daily folate supplements throughout their childbearing years because the extra dosage can help even those women who have trouble metabolizing folate. “It's a simple thing, but it has been shown to reduce birth defects,” he says, adding that many pregnancies are unplanned, and by the time many women realize they're pregnant, it may be too late.