The incidence of neural tube defects (NTDs) is about 1.3 cases per 1000 live births. The higher incidence of NTDs occurs among certain ethnic groups, and geographic areas. The fetal morbimortality is high and the treatment for those babies who live is expensive with pour quality of live. It is unclear what biochemical mechanism involving folate explain the relationship of this vitamin to the pathogenesis of NTDs. However elevated concentrations of homocysteine or decreased methionine concentrations could be interfere with closure of the neural tube. The pharmacologic periconceptional intake of 0.4-4.0 mg/day of folic acid reduces the risk of occurrent NTDs by approximately 40-75%. A relatively high dietary intake of folate may also reduce the risk.