Epidemiology, pathophysiology, and interventions for postpartum depression: Systematic review

Figure 3 Parallel psychophysiological pathways underlying postpartum depression. This figure illustrates five interrelated biological and psychological pathways implicated in the pathogenesis of postpartum depression: Hormonal withdrawal, hypothalamic-pituitary-adrenal axis dysregulation, inflammatory activation, gut-brain axis disruption, and psychological vulnerability. The updated hormonal model incorporates recent positron emission tomography/magnetic resonance spectroscopy findings linking postpartum estrogen withdrawal to decreased allopregnanolone levels and impaired GABA_a signaling, which contribute to emotional dysregulation. Each pathway interacts with mood, cognition, and behavior through distinct yet interconnected mechanisms in biologically susceptible individuals. CRP: C-reactive protein; IL-6: Interleukin-6; SCFA: Short-chain fatty acid; 5-HT: 5-hydroxytryptamine; GABA_a: Gamma-aminobutyric acid type A receptor.