Abstract: Objective To examine the folic acid supplementation compliance of women of childbearing age after the policy of supplementing folic acid in the periconceptional period has been implemented for many years, to explore the factors affecting folic acid supplementation, and to provide scientific evidence for determining the specific measures for supplementing folic acid in key populations. Methods A county-based 1∶1 matched case-control study was conducted in a county in Shandong Province. Questionnaire survey was conducted between mothers of children with or without birth defects during the study period, who were defined as case group and control group, respectively. Paired t test, χ2 test and conditional multivariate Logistic regression analysis were used to examine folic acid supplementation compliance. Unconditional multivariate Logistic regression analysis was used to explore the factors affecting pre-pregnancy folic acid supplementation compliance. Results A total of 263 cases of birth defects were diagnosed at the study site, and 180 cases were enrolled in case group and 180 cases were enrolled in control group. (1)In the periconceptional period, the folic acid intake proportions of case group and control group were 81.67% and 88.33%(P=0.111), and the regular intake proportions were 10.56% and 15.00%(P=0.229). In the last three months before pregnancy, the folic acid intake proportions were 33.33% and 40.00%(P=0.213), and the days of intake were(19.63±32.05)and(26.32±36.33)d(P=0.053). (2)The risk of birth defects decreased with the increase of folic acid supplementation days in the last three months before pregnancy(OR=0.933, 95%CI: 0.872-0.999, P=0.046). (3)The main influencing factors for pre-pregnancy folic acid administration were unintended pregnancy(OR=2.825, 95%CI: 1.303-6.127, P=0.009)and the first pregnancy(OR=2.657, 95%CI: 1.171-6.029, P=0.019). Conclusion Women of childbearing age have a relatively high proportion of folic acid supplementation in the periconceptional period but poor compliance with folic acid before pregnancy. In order to improve the pre-pregnancy folic acid utilization, the universal education of folic acid action for first pregnant woman should be strengthened. The fully prepared pregnancy can be actively advocated to avoid unintended pregnancy and improve compliance with folic acid before pregnancy.

Key words: Folic acid, Pre-pregnancy, Birth defects, Compliance, Influencing factors