NEW YORK (Reuters Health) – A new study finds that South Carolina’s rate of spina bifida and similar birth defects fell substantially after more women began taking folic acid — adding to evidence of the B vitamin’s benefits during pregnancy.
Since 1998, the U.S. has required manufacturers to add folic acid to enriched flours, breads, cereals, pasta, corn meal and other grain products. The move was based on research showing that folic acid during pregnancy can cut the risk of neural tube defects.
For the new study, reported online February 24th in the Journal of Pediatrics, researchers looked at rates of neural tube defects in South Carolina from 1992 to 2009.
Infants born in South Carolina have historically had a higher rate of neural tube defects compared with the U.S. average. But during the study period, the rate of isolated neural tube defects fell from 1.4 for every 1,000 births and fetal deaths, to about 0.6 per 1,000.
And from 1998 to 2005, the average rate of spina bifida and anencephaly — which account for most neural tube defects — was 0.69 per 100,000. That was identical to the national average.
Folic acid would appear to take the credit, according to Dr. Roger E. Stevenson and colleagues at the Greenwood Genetic Center in South Carolina.
Based on interviews with South Carolina women ages 15 to 45 throughout the study period, the proportion taking folic acid on a regular basis rose from 8% to 35%.
The authors did not ask women how much folic acid they took, but experts recommend that women who may become pregnant get 400 micrograms from multivitamins or fortified foods.
Despite the positive findings from the current study, there is also room for improvement, according to Dr. Stevenson’s team. They point to the fact that by the end of the study period, only 35% of women were taking folic acid — despite the fact that two-thirds were aware of the vitamin’s benefits.
But folic acid may only do so much.
Obesity and type 2 diabetes in the mother are two other factors linked to a higher-than-average risk of neural tube defects. And in this study, increasing use of folic acid did not eliminate the risk associated with diabetes, Dr. Stevenson and his colleagues point out.
That finding, the researchers write, “calls for greater attention” to diabetes prevention in women of childbearing age. They add that studies could also look at whether higher doses of folic acid are necessary for women with diabetes.
J Pediatrics 2011.