Folic Acid Supplement Intake in Early Pregnancy Increases Risk of Gestational Diabetes Mellitus: Evidence From a Prospective Cohort Study

Folic acid (FA) is well known for its preventive effect on neural tube defects, and recommendations for FA supplement before and during pregnancy have been well established all over the world. Since increased consumption of FA has been prevalent, concerns about its negative consequences have been raised. Diverse adverse effects of FA have been identified, ranging from an increased risk of oral cleft malformations, asthma/respiratory tract infections, and small-for-gestational-age infants to the more serious effect of a potential increased risk of cancers. Previous studies have suggested that a high maternal folate concentration is associated with an increased risk of insulin resistance in children and gestational diabetes mellitus (GDM) (1). In addition, animal experiments have reported that maternal high-FA supplement promotes glucose intolerance and insulin resistance in male mouse offspring fed a high-fat diet (2). However, …