The findings indicate substantial increases in serum and RBC folate concentrations among women of childbearing age. A household interview and a physical examination were conducted for each survey participant. Similar results were obtained for RBC folate, a better measure of longterm folate status. In addition, PHS recommended and FDA subsequently mandated fortification of the food supply to deliver folic acid to the general population. Because up to half of pregnancies are unplanned and NTDs occur early in pregnancy, before many women are aware that they are pregnant, food fortification is a particularly important approach to folic acid delivery.
Preliminary analyses indicate that the prevalence of supplement use was similar in the two surveys.
Despite the substantial increase in blood folate concentrations documented for U.S. women of childbearing age, full evaluation of the health impact of folic acid fortification on NTD occurrence will require additional information. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. Food and Drug Administration. Wright JD, Bialstosky K, Gunter EW, et al. US Department of Health and Human Services, CDC, National Center for Health Statistics.