Folic Acid and the Prevention of Neural-Tube Defects

In 1991, a randomized trial funded by the Medical Research Council demonstrated that folic acid supplementation before pregnancy and during its early stages markedly reduced the risk of neural-tube defects in newborns.1 This finding — which indicated that neural-tube defects may be considered to represent a vitamin-deficiency disorder — led to the recommendation that all women who are planning to become pregnant should take folic acid...