The neurobiology of postpartum depression.

Postpartum depression (PPD) is the most common complication of pregnancy, posing significant health risks for both women and their children. Unlike other subtypes of major depressive disorder (MDD), PPD is thought to be biologically relatively homogenous, as it is precipitated by a specific biological trigger - the profound hormonal shifts associated with pregnancy and delivery. However, the underlying pathophysiology of PPD is still unclear, with a variety of biological factors likely at play. In this review, we examine recent biological findings related to neuroimaging, the hypothalamic-pituitary-adrenal (HPA) axis, neuroactive steroids (NAS), epigenetics, and extracellular vesicles (EVs) and explore processes that may be unique to PPD versus those shared with MDD, along with avenues of future research aimed at PPD prevention and treatment.