Publication:

Folic acid supplementation in pregnancy: established benefits, emerging evidence and public health implications

Folic acid supplementation during pregnancy is one of the most effective nutritional interventions for preventing neural tube defects (NTDs). This narrative review synthesizes evidence from randomized controlled trials, observational studies, systematic reviews, and mechanistic research to evaluate the role of folic acid in maternal and foetal health. Robust and consistent evidence demonstrates that periconceptional folic acid supplementation substantially reduces the risk of NTDs, providing the scientific basis for global supplementation guidelines and mandatory food fortification programmes. Beyond NTD prevention, maternal folate status has been associated with a range of pregnancy and offspring outcomes, including foetal growth, neurodevelopment, and long-term metabolic health. These associations are supported by emerging evidence from epidemiological and experimental studies, with epigenetic mechanisms proposed as a key biological pathway. However, evidence for these broader effects remains less consistent and is largely observational in nature. In the post-fortification era, concerns have emerged regarding excessive folic acid intake, including the potential accumulation of unmetabolised folic acid and disruption of balanced one-carbon metabolism. This review critically evaluates established benefits, emerging evidence, and ongoing controversies surrounding folic acid supplementation in pregnancy, and identifies priorities for future research and public health practice.