Toivonen KI, et al. - Researchers analyzed studies that reported the prevalence of preconception folic acid supplementation, as recommended by guidelines to prevent neural tube defects (NTDs) in offsprings, to synthesize the estimates of adherence to this recommendation across different countries worldwide. In addition, they also assessed the differences based on demographic, methodological, and study quality characteristics. A high variance was reported in regards to the prevalence of preconception folic acid supplementation worldwide. Data indicated that sufficient folate levels to prevent NTDs may not be achieved by many women. In studies comprising more highly educated samples, conducted in fertility clinics, and assessed folic acid use via self-report, the reported prevalence of folic acid supplementation was higher.