Folic acid supplementation and risk for imperforate anus in China

Maternal consumption of folic acid before pregnancy and during early pregna ncy is associated with a reduced risk for some birth defects. Whether folic acid can reduce the risk for imperforate anus is unknown. As part of a pub lic health campaign conducted in China from 1993 through 1995, the outcomes of pregnancies of greater than or equal to 20 weeks' gestation were evalua ted among women using folic acid supplements. The women were asked to take one pill containing 400 mug of folic acid (without other vitamins) every da y from the time of their premarital examination until the end of their firs t trimester of pregnancy. Rates of imperforate anus and risk ratios for imp erforate anus among the offspring of these women were calculated according to folic acid use. Among the offspring of women who took folic acid and wom en who did not take folic acid, 20 and 30 infants with imperforate anus wer e identified, respectively. The rate of imperforate anus was 3.1 per 10,000 among the offspring of women who did not take folic acid and 1.6 per 10,00 0 among the offspring of women who took folic acid; adjusted for maternal a ge, the risk ratio was 0.59 (95% confidence interval: 0.33, 1.07). Daily ma ternal consumption of 400 mug of folic acid before and during early pregnan cy may reduce the risk for imperforate anus.