Prevention of neural-tube defects with folic acid in China

Background Periconceptional use of multivitamins containing folic acid can reduce a woman's risk of having a baby with a neural-tube defect. Methods As part of a public health campaign conducted from 1993 to 1995 in an area of China with high rates of neural-tube defects (the northern regio n) and one with low rates (the southern region), we evaluated the outcomes of pregnancy in women who were asked to take a pill containing 400 mu g of folic acid alone daily from the time of their premarital examination until the end of their first trimester of pregnancy. Results Among the fetuses or infants of 130,142 women who took folic acid a t any time before or during pregnancy and 117,689 women who had not taken f olic acid, we identified 102 and 173, respectively, with neural-tube defect s. Among the fetuses or infants of women who registered before their last m enstrual period and who did not take any folic acid, the rates of neural-tu be defects were 4.8 per 1000 pregnancies of at least 20 weeks' gestation in the northern region and 1.0 per 1000 in the southern region. Among the fet uses or infants of the women with periconceptional use of folic acid, the r ates were 1.0 per 1000 in the northern region and 0.6 per 1000 in the south ern region. The greatest reduction in risk occurred among the fetuses or in fants of a subgroup of women in the northern region with periconceptional u se who took folic acid pills more than 80 percent of the time. In the south ern region the reduction in risk among the fetuses or infants of women with periconceptional use of folic acid was also significant (reduction in risk , 41 percent; 95 percent confidence interval, 3 to 64 percent). Conclusions Periconceptional intake of 400 mg of folic acid daily can reduc e the risk of neural-tube defects in areas with high rates of these defects and in areas with low rates. (N Engl J Med 1999;341:1485-90.) (C) 1999, Ma ssachusetts Medical Society.