The microbiota-gut-brain axis in postpartum depression: a review of microbial mechanisms and therapeutic potential

Postpartum depression (PPD), a common but mechanistically uncertain mood disorder, occurs in 10-15% of mothers and seriously affects maternal and infant health. Recent evidence suggests that alteration of gut microbiota could dysregulate gut-brain axis functioning, which is potentially linked to the pathogenesis of PPD. This review innovatively synthesizes up-to-date preclinical and clinical evidence to illustrate relevant mechanisms, including microbial metabolite signaling, immune-inflammatory pathways, and neuroendocrine disruptors. Furthermore, the therapeutic potential of microbial-targeting approaches, including probiotics, dietary changes, and fecal microbiota transplant, to remedy PPD by restoring microbial health is discussed. Nevertheless, several notable limitations, translational uncertainties and major knowledge gaps still exist in this field. Most current evidence derives from cross-sectional observations, and well-designed longitudinal human studies are urgently needed to confirm causal relationships. In addition, available microbiota-related interventions have not yet developed into mature precision microbiome therapeutics. Against this background, this study proposes a microbiome framework connecting basic science and clinical applications that may help unravel the etiology and treatment of PPD.