The prevalence of neural tube defects (NTDs) fell by nearly half after folic acid fortification of foods was introduced in Canada in 1998, according to a study in the July 12 issue of the 

Philippe De Wals, PhD, from Laval University in Quebec, Canada, and colleagues examined the effect of folic acid fortification of foods in Canada on the prevalence of NTDs. Fortification was introduced in 1998 and the study examined 1.9 million live births, stillbirths, and pregnancy terminations due to fetal anomalies from 1993–2002. 

The researchers found there were 2,446 subjects with NTDs over this period. The prevalence of NTDs fell by 46% after folic acid fortification was introduced, from 1.58 to 0.86 per 1,000 births. The decrease was greatest in areas of Canada where the rate of defects was high before fortification, and fortification removed most geographical differences in prevalence. 