Prevalence and determinants of inadequate use of folic acid supplementation in Japanese pregnant women: the Japan Environment and Children’s Study (JECS)

Objective: The aim of the study was to clarify the prevalence and determinants of inadequate use of folic acid supplementation in pregnant Japanese women. Methods: This study was part of the Japan Environment and Children’s Study, a nationwide and government-funded birth cohort study. We collected information on the use of folic acid supplementation before and during pregnancy and characteristics of participants using self-administered questionnaire. Results: Among 9849 women who completed the data collection for this study, the prevalence of inadequate users was 92.6% of the total population and varied from 84.5% to 96.2% among regions. On the basis of multivariate logistic regression analysis, younger age, not married, lower family income, multipara, natural conception and no history of spontaneous abortion were found to be determinants for inadequate users of folic acid supplementation. Conclusion: Most Japanese pregnant women show inadequate folic acid supplementation use. Japanese women of child-bearing age need to be specifically informed about the need for periconceptional intake of folic acid to prevent neural tube defects.