Prevention of neural tube defects with folic acid: The Chinese experience

Abstract

Neural tube defects (NTDs) are a group of congenital malformations of the central nervous system that are caused by the closure failure of the embryonic neural tube by the 28^th day of conception. Anencephaly and spina bifida are the two major subtypes. Fetuses with anencephaly are often stillborn or electively aborted due to prenatal diagnosis, or they die shortly after birth. Most infants with spina bifida are live-born and, with proper surgical treatment, can survive into adulthood. However, these children often have life-long physical disabilities. China has one of the highest prevalence of NTDs in the world. Inadequate dietary folate intake is believed to be the main cause of the cluster. Unlike many other countries that use staple fortification with folic acid as the public health strategy to prevent NTDs, the Chinese government provides all women who have a rural household registration and who plan to become pregnant with folic acid supplements, free of charge, through a nation-wide program started in 2009. Two to three years after the initiation of the program, the folic acid supplementation rate increased to 85% in the areas of the highest NTD prevalence. The mean plasma folate level of women during early and mid-pregnancy doubled the level before the program was introduced. However, most women began taking folic acid supplements when they knew that they were pregnant. This is too late for the protection of the embryonic neural tube. In a post-program survey of the women who reported folic acid supplementation, less than a quarter of the women began taking supplements prior to pregnancy, indicating that the remaining three quarters of the fetuses remained unprotected during the time of neural tube formation. Therefore, staple food fortification with folic acid should be considered as a priority in the prevention of NTDs.

Keywords: Neural tube defects; Folic acid; Folate; Supplementation; Fortification

Core tip: Neural tube defects are severe congenital malformations of the central nervous system. The prevalence of these defects in China is among the highest in the world. Low intake of dietary folate is to be blamed. The provision of free-of-charge folic acid supplements to all women who live in rural areas and plan to become pregnant has been implemented since 2009. However, fortification of staple foods with folic acid has not been planned. It is time to consider fortification since many pregnancies are unplanned and therefore it is difficult for a woman to take folic acid supplements from before pregnancy.