The effect of folic acid and B12 vitamin supplementation on mental well-being in pregnant women: A possible role in the prevention of postpartum depression

Background: Postpartum depression (PPD) is a common and serious psychiatric disorder that affects 10–30% of mothers worldwide. Untreated PPD is associated with adverse consequences for both maternal well-being and child neurodevelopment. While the pathophysiology of PPD is multifactorial and not fully elucidated, nutritional factors - particularly B-vitamins - have emerged as modifiable risk contributors due to their roles in neurodevelopment, neurotransmitter synthesis. Material and Methods: This narrative review aims to evaluate the current evidence on the relationship between B-vitamin status during pregnancy and maternal mental health, with a focus on their potential preventive effect against postpartum depression. A literature search was conducted in PubMed and Google Scholar for studies published between 1997 and May 2025. Eligible articles included clinical trials, observational studies, and meta-analyses published in English or Polish. Results: Deficiencies in folate and vitamin B12 disrupt the folate cycle, leading to hyperhomocysteinemia, oxidative stress, and impaired monoamine neurotransmitter synthesis, which are implicated in the pathogenesis of depression. Several studies indicate that low levels of B6 (pyridoxine), B9 (folate), and B12 (cobalamin) are associated with increased risk and severity of depressive symptoms during and after pregnancy. Supplementation, particularly with pyridoxine and folate, has shown promising results in improving maternal mood and reducing depressive symptoms. Conclusion: B-vitamin supplementation during pregnancy may represent a low-risk, cost-effective strategy to support maternal mental health and potentially reduce the incidence of postpartum depression. Further randomized controlled trials are warranted to confirm these findings.