Primary Prevention of Neural Tube Defects

Abstract

Studies had proven that supplementation of women of childbearing age with folic acid can prevent up to 70% of all cases of NTDs (Laurence et al 1981, MRC Vitamin Study Research Group 1991). These researches led to international recommendations that all women of childbearing age consume 400 micrograms of folic acid daily for the prevention of neural tube defects at least 1 month before and throughout the first trimester of pregnancy (CDC 1992, Institutes of Medicine 1998, WHO 2002). Three potential approaches were advocated to increase level of folic acid consumption among the general population: fortification of food supply, improvement of dietary habits and use of dietary supplements (CDC, 1992). In some countries such as Canada and the USA, these recommendations led to the fortification of all enriched grain products with folic acid. This action decreased the occurrence of spina bifida by 31% and anencephaly by 16% (CDC 2004) and thus was considered as a partial success. As for the change in eating habits, meeting dietary recommendations for grain intake is an important step to achieving the recommended daily intake for folic acid. Studies have shown that non pregnant women of childbearing age reported an average daily consumption of 128 mcg of folic acid, representing only 32 percent of the daily recommended amount (Yang et al. 2007). These facts imply that most women still need to daily consume a dietary supplement containing folic acid at the recommended dose (400 μg) in order to prevent pregnancies with NTDs. Despite all this, several studies have shown a low consumption of folic acid supplements worldwide: numbers vary from prevalence as low as 7.5% in Lebanon (Nasr Hage et al 2011) to the highest percentage of 40 % in Canada and the USA (Morin et al. 2002; Petrini et al, 2008). These percentages remain far from the “Healthy people 2010” goal aiming that a minimum of 80% of women of childbearing age consume at least 400 mcg of folic acid daily in the periconception period. Levels of awareness and knowledge have been studied extensively in women of childbearing age in order to explain the low prevalence of folic acid intake with variable results in different countries. Although these levels of awareness and knowledge were thought to explain low levels of folic acid consumption, a systematic review of the literature showed that variable interventions on folic acid increased women’s awareness from 60% to 72% and knowledge