Early Miscarriage Linked to Lack of Folic Acid
Study finds 50% increased risk in women without enough of it
TUESDAY, Oct. 15, 2002 (HealthDayNews) -- Low blood levels of folic acid increase the risk of early miscarriage, suggests a new Swedish-American study that gives any woman who might become pregnant another good reason to get enough of the supplement.
Grain products in the United States have been fortified with folic acid since 1998, by order of the U. S. Food and Drug Administration (FDA), to reduce the risk of neural tube birth defects such as spina bifida. Sweden does not fortify its foods, so researchers at the U.S. National Institute of Child Health and Human Development (NICHD) collaborated with the Karolinska Institute in Stockholm to study the relationship between folic acid intake and miscarriage.
The researchers compared blood levels of folate, the body's version of folic acid, in 468 Swedish women who miscarried between the sixth and twelfth weeks of pregnancy and 912 women whose pregnancies were proceeding normally at that time. They looked specifically at women whose folate level was below 4.9 nanograms per milliliter (ng/mL), the point at which Swedish authorities recommend folic acid supplements.
Women with folate readings below 4.9 ng/mL had a 50 percent increased risk of early miscarriage, the researchers report in tomorrow's issue of the Journal of the American Medical Association. No adverse effect was found for higher readings, even those above 9.0 ng/mL.
"There has been a question about whether there are other benefits of taking folic acid, other than reducing the risk of neural tube defects," says Dr. James L. Mills, chief of the NICHD pediatric epidemiology branch. "Our findings suggest that there is a potential for reducing the risk of miscarriage."
If Mills sounds somewhat tentative, it is because the mechanism by which folate acts is unknown. "We haven't the slightest idea," he says.
However, he is not tentative when he talks about the public health implications of the study. "Every woman 15 to 44 should be taking folic acid routinely, 400 micrograms a day," Mills says. "About half the women in the United States who get pregnant every year don't know immediately that they are pregnant. If you wait until you know you are pregnant, it is too late."
In coordination with the FDA action, the U.S. Institute of Medicine recommended in 1998 that every woman of childbearing age should receive 400 micrograms of folic acid every day. That amount is easily available in multivitamin supplements, Mills says. Natural sources of folic acid include beans, leafy green vegetables and citrus fruits.
Can a woman take too much folic acid? That is "a hotly debated issue," says Dr. Nancy Green, medical director of the March of Dimes Birth Defects Foundation, but for most women the answer is "probably not."
Some women are advised to take much more than the generally recommended amount, Green says, notably women who have already borne a child with a neural tube defect or those who have such defects themselves. They are told to take 10 times the standard dose, she says.
Other women who probably would benefit from a higher-than-average intake include those who are taking medication to control seizures, who are obese or who have diabetes, Green says. "To ensure getting sufficient amounts, we recommend that women take a synthetic form, in a multivitamin preparation, in addition to eating enriched cereals and a healthy diet," she says.
What To Do
For more on folic acid and pregnancy, consult the March of Dimes Birth Defects Foundation or the National Center for Birth Defects and Developmental Disabilities.