Folate Metabolism and L-5-Methyltetrahydrofolate in Nausea and Vomiting of Pregnancy: Current Evidence and Knowledge Gaps

Nausea and vomiting of pregnancy (NVP) are common symptoms of early gestation and may substantially impair quality of life. The severe form, hyperemesis gravidarum (HG), is associated with weight loss, dehydration, and metabolic disturbances. Objective. To summarize current evidence on the potential role of metabolic and nutritional factors in NVP/HG, with a particular focus on folate metabolism and biologically active folate forms, including L-5-methyltetrahydrofolate (5-MTHF), and to identify existing knowledge gaps and directions for future research. Methods. Narrative review of literature from PubMed/MEDLINE, Scopus and Web of Science (2000–2024). Results. Current evidence suggests that metabolic and nutritional factors may contribute to NVP/HG; however, studies specifically evaluating active folate forms such as 5-MTHF remain scarce. Conclusions. Further prospective studies assessing active folate forms and biomarkers of one-carbon metabolism are warranted.