Postpartum depression (PPD) is a serious mental disorder that can occur in the postpartum period with dramatic physiological and emotional changes in all maternal organisms [1]. PPD is commonly recognized as a subtype of major depressive disorder (MDD), affecting 10–20% of all new mothers within 4 weeks after childbirth [2]. PPD has not only profound adverse effects on mothers but also negatively impacts their infants owing to the absence of maternal care and mother-infant social interactions [3]. In severe situations, patients may even be more likely to commit infanticide and baby abuse [4]. Although the dramatic fluctuation of ovarian hormones during postpartum and the abnormal secretion of glucocorticoids are widely considered as contributors to PPD [5–7], but an association between many other factors involved in energy metabolism, neurodegeneration, and immune response and the pathophysiology of PPD has been identified [8]. Until now, the knowledge about the etiology of PPD is incomplete and the underlying mechanisms are largely unclear.
