CHICAGO—Women who consume a high-quality diet at least one year before pregnancy have a reduced risk of delivering a baby with birth defects, including neural tube defects and orofacial clefts, according to a new study published in the Archives of Pediatrics & Adolescent Medicine.
Researchers from Stanford University used data from the National Birth Defects Prevention Study to examine whether better maternal diet quality was associated with reduced risk for selected birth defects. Data were collected in 10 states from pregnant women with estimated due dates from October 1997 through December 2005. Information was collected via telephone interviews with 72% of case and 67% of control mothers. Included in the analysis were 936 cases with neural tube defects, 2,475 with orofacial clefts, and 6,147 controls without birth defects. Mothers reported their food intake using a questionnaire.
The researchers developed two diet quality indices that focused on overall diet quality based on the Mediterranean Diet (Mediterranean Diet Score or MDS) and USDA’s Food Guide Pyramid (Diet Quality Index or DQI).
They found increasing diet quality based on either index was associated with reduced risks for the birth defects studied. Most mothers of controls were non-Hispanic white and had more than a high school education; 19% smoked, 38% drank alcohol, and 78% took folic acid-containing supplements during early pregnancy; and 16% were obese. Women who were Hispanic had substantially higher values for the DQI and the MDS, whereas values were lower among women with less education and women who smoked, did not take supplements, or were obese.
Based on two diet quality indices, higher maternal diet quality in the year before pregnancy was associated with lower risk for neural tube defects and orofacial clefts. This finding persisted even after adjusting for multiple factors such as maternal intake of vitamin/mineral supplements.
"These results suggest that dietary approaches could lead to further reduction in risks of major birth defects and complement existing efforts to fortify foods and encourage periconceptional multivitamin use," the authors concluded.
In an accompanying editorial, David R. Jacobs, Jr., Ph.D., from the University of Minnesota, noted that while maternal intake of folate is important for fetal development, recent studies suggest the supplemental folic acid may have adverse health effects on older adults.
"The importance of the findings of Carmichael et al lies in showing that women obtain benefit from the consumption of a high-quality diet, beyond the benefits derived through grain fortification. This raises the question of whether a high-quality diet alone may be sufficient to prevent NTDs (neural tube defects), a strategy that would also remove the potential harm from fortification."
