Oxytocin Mediates a Calming Effect on Postpartum Mood in Primiparous Mothers

Objectives: The current study sought to characterize changes in salivary oxytocin (OT) secretion patterns across the breastfeeding cycle, and to evaluate whether breastfeeding has a positive effect on mood disturbances related to postpartum depression, via endogenous OT release. Materials and Methods: Twenty-four primiparous mothers who delivered vaginally at term and were exclusively breastfeeding were examined 4-5 days postpartum. Salivary OT was measured using enzyme immunoassays at 30 minutes before breastfeeding (baseline), during breastfeeding (feeding), and 30 minutes after completing breastfeeding (postfeeding). In addition, maternal mood changes were evaluated at baseline and postfeeding using the Profile of Mood States (POMS) questionnaire. Results: OT levels rose significantly during feeding (p(corr)<.05) and postfeeding (p(corr)<0.05), compared with baseline. POMS scores for Tension-Anxiety were decreased postfeeding compared with baseline (p < 0.001). This decrease was significantly associated with increased OT (feeding minus baseline: r=-0.52, r(part)=-0.51, postfeeding minus baseline: r=-0.53, r(part)=-0.52, ps < 0.05). POMS scores for Fatigue and Confusion also decreased, while Vigor significantly increased. Significant correlations were found between Fatigue decreases and OT increases (feeding minus baseline: r=-0.48, r(part)=-0.53, postfeeding minus baseline: r(part)=-0.60, ps < 0.05). This result partially contradicted with the finding of no correlation between increased Vigor and increased OT. Conclusions: OT is released across the breastfeeding cycle and can be detected with salivary measurement. This OT release exhibited a temporary anxiolytic-like calming effect on postpartum maternal mood disturbances.