Folate Supplement Not as Effective in Preventing Neural Tube Defects in Infants of Overweight, Obese Women, Study Says

Although Canada's folate fortification program overall has decreased pregnant women's risk of delivering an infant with
neural tube defects, the benefit is much weaker among overweight and obese women than in women of normal weight, according to
a study published in the Feb. 1 issue of the journal Obstetrics & Gynecology, Reuters
Health reports. Dr. Joel Ray, clinical scientist and assistant professor at the University of Toronto, and colleagues studied 420,362 pregnant women in Ontario, Canada, between 1994 and
2000 (Boggs [1], Reuters Health, 2/1). Canada in 1997 in an effort to reduce the number of infants born with
NTDs, such as spina bifida, mandated that all refined wheat flour be fortified with folic acid. Following fortification, the
offspring of women whose prenatal weights were in the highest quartile had a 44% reduction in risk of neural tube defects.
However, the risk of NTDs for infants of women in the first, second and third quartiles of weight was reduced 68%, 70% and
90%, respectively. Before the advent of the fortification program, women whose weights were in the top quartile were 1.4
times as likely as all of the other women in the study to deliver an infant with an NTD. However, after fortification, women
in the top quartile were 2.8 times as likely as other women to have an NTD-affected infant. Ray said that overweight and
obese women might need higher doses of folic acid to prevent NTDs or might have an undiagnosed risk factor related to
obesity, such as diabetes, that increases their risk of NTDs and is not improved by folic acid supplements. "All women should
continue to take folic acid tablet supplements before pregnancy, and women who are overweight should consider a small degree
of weight reduction before pregnancy," Ray said, adding, "Long-term maintenance of a normal weight, beyond pregnancy, would
seem to be one of the most important interventions for maintaining a woman's health over the many years that follow
pregnancy" (Boggs [2], Reuters Health, 2/1).


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