Periconceptional folic acid and neural tube defects: public health issues.

This review examines evidence linking periconceptional folic acid intake to neural tube defects (NTDs) and related public health issues in the United States and developing countries. Sources of information were identified through on-line searches (Medline, UCAT-University of Connecticut) and by contacting researchers in the field. The distribution of NTDs varies across regions. Recurrent NTDs can be prevented with high-dosage folic acid supplementation during periconception, but it is not clear if such a protective effect can be achieved with lower dosages or in low-NTD-risk populations. Overall, it appears that women with a previous NTD pregnancy should receive folic acid supplementation during periconception under medical guidance. Dietary counseling regarding foods rich in folate should be given to all women of childbearing age. However, primary prevention of NTDs through widespread food fortification with folic acid seems unwarranted in both the United States and developing countries due to the low prevalence of NTDs relative to other problems and a potentially unfavorable benefit/risk ratio.