FOLIC-ACID AND THE PREVENTION OF BIRTH-DEFECTS

Thirty years ago, it was suggested that maternal intake of certain vit amins during pregnancy affected the incidence of serious fetal malform ations. Subsequent research has revealed that folate (folic acid), a B vitamin, plays a crucial role in the development of the central nervo us system during the early weeks of gestation, which is generally befo re the pregnancy is confirmed. In a significant number of embryos, an inadequate supply of folate at this time leads to a failure of the pri mitive neural tube to close and differentiate normally and results in neural tube birth defects (NTD). Numerous studies have confirmed the i mportance of an adequate intake of folate during the weeks just before and after conception. Overall, the data predict that if women consume multivitamin supplements containing folic acid during the periconcept ional period, the number of children born with serious malformations ( such as spina bifida and anencephaly) could be reduced by half. Althou gh programs to increase dietary folate intake of potential mothers may be effective in reducing NTD, the only proven and practical preventiv e measure currently available is to take oral multivitamin supplements containing folic acid. Multivitamin supplementation has also been ass ociated with reduced incidence of other congenital malformations. Curr ent research is focusing on the role of micronutrients in embryogenesi s, and on methods to identify prospective mothers at increased risk fo r bearing a child with NTD or with other major malformations shown to occur at reduced frequency with multivitamin supplementation. Of equal importance is the development of methods to communicate current knowl edge as a public health measure.