Postpartum depression (PPD) is the most common postnatal psychiatric disorder, and it represents a considerable problem to the health and well-being of women and their families. Several pathogenic mechanisms have been identified in PPD, and recently, oxytocin (OT), known to be involved in childbirth and lactation, has drawn attention as a possible diagnostic and therapeutic tool in this disorder. The aim of this review was to assess and summarize the current literature on the relationship between OT as a potential depressive biomarker and depression in the perinatal period. We conducted a literature search on four electronic databases (Pubmed, PsycINFO, Web of Science, and Science Direct) by applying the following search terms: oxytocin AND (postpartum OR postnatal OR perinatal OR peripartum) AND (depression OR depressive). Six studies were included and a total of 620 pregnant women were recruited and completed the follow-up. Depressive symptoms were evaluated using self-report scales, and in three studies, the diagnosis of major depression was additionally confirmed using semi-structured interviews. Peripheral OT levels and depression were assessed during pregnancy and/or after delivery. Higher OT levels were associated with lower depressive symptoms, even if this association lacked statistical significance in two studies. Although some studies are beginning to shed light upon the complex nature of OT's effect in depression, its role as a diagnostic and therapeutic tool in PPD is still unclear. Future research is needed to clarify the neuroendocrinological and psychosocial particularities of mothers with PPD and to define a specific profile associated with OT dysfunction.
Keywords: Depressive symptoms; Oxytocin; Perinatal depression; Postpartum depression.