Association Between Maternal Mood and Oxytocin Response to Breastfeeding

Background: Postpartum depression is associated with reduced breastfeeding duration. We previously hypothesized that shared neuroendocrine mechanisms underlie this association. We sought to measure the association between maternal mood and neuroendocrine response to breastfeeding. Methods: We conducted a longitudinal cohort study of women recruited during pregnancy who intended to breastfeed. Baseline depression and anxiety history were assessed with a structured clinical interview. We measured mood symptoms using validated psychometric instruments, and we quantified affect and neuroendocrine responses to breastfeeding during laboratory visits at 2 and 8 weeks postpartum. Results: We recruited 52 women who intended to breastfeed, among whom 47 completed 8-week follow-up. Duration and intensity of breastfeeding through 8 weeks were similar among mothers with lower versus higher anxiety and depression scores. In the third trimester, oxytocin was inversely correlated with Edinburgh Postnatal Depression Scale (EPDS) score (p = 0.03). We did not find differences in neuroendocrine profile during breastfeeding at 2 weeks postpartum. Among the 39 women who breastfed at 8 weeks postpartum, oxytocin area under the curve during breastfeeding was inversely correlated with maternal EPDS and STAI-State and STAI-Trait anxiety scores (all p <= 0.01). Higher anxiety and depression scores was further associated with lower oxytocin (group p < 0.05) during feeding. During feeding at both visits, higher anxiety and depression scores were also associated with more negative affect: mothers reported feeling less happy and more depressed, overwhelmed, and stressed during feeding than women with lower scores. Conclusion: Symptoms of depression and anxiety were associated with differences in oxytocin response and affect during breastfeeding.