The risk of menstrual abnormalities after preconceptional use of folic acid or a folic acid-containing multivitamin in Chinese women.

The associations of preconceptional folic acid use with menstruation-related changes were examined by a retrospective study through 219 questionnaires. The kind of folic acid (alone or with other vitamins), the using time and frequency, the menstrual regularity, the cycle length before and after use, and other menstruation-related changes after use were obtained. Two hundred of 219 participants were users, and menstruation-related changes occurred in 32 women, with abnormalities of involvement being longer cycles (increase of 3-20days, 7.7 +/- 4.8days), shorter cycles (decrease of 3-7days, 5.7 +/- 2.3days), irregular cycles, less blood loss, bleeding or spotting between cycles, and algomenorrhea. Seventeen women stopped using folic acid or folic acid-containing multivitamin, and sixteen of the seventeen women experienced at least one menstruation before conception. Fifteen of sixteen women found complete recovery, indicating the high possibility that these changes were attributed to the use of folic acid or folic acid-containing multivitamin.