A Clinical Translational Approach to Understanding Oxytocin and Maternal-Infant Bonding in Postpartum Mothers with Opioid Use Disorder

Abstract

It is currently unknown whether oxytocin mechanisms, the hormone underlying maternal bonding, are altered when there is a damaged reward system from opioid use disorder (OUD), and the impact this may have on the maternal/infant bonding relationship. This is a critical gap in the literature that this dissertation seeks to investigate. In paper 1, a scoping review found in the clinical literature that those with OUD had lower levels of endogenous oxytocin, and overall that exogenous oxytocin may benefit individuals with substance use disorders, particularly those with an alcohol use disorder or OUD. In paper 2, a study found no significant differences in mean oxytocin levels between mothers with (n=6) and without OUD (n=7) before (mean difference: 15.23 pg/mL, p=0.271, d = 0.67) or after a caregiving activity (post activity 1: 11.26, (p=0.441, d=0.78; post activity 2: p=0.320, d=1.14). While bonding measures did not significantly differ, there was a marginal non-significant difference after the caregiving activity (p=0.065), where mothers with OUD reported feeling 100% connected to their baby, compared to 86.9% among those without OUD; suggesting a possible disconnect between the physiological oxytocin response and subjective connection. Additionally, in paper 3 a multivariate linear regression showed that psychological distress emerged as the strongest predictor of bonding (p<0.000), with oxytocin showing no significant effect in either group (n=24 with OUD, n=17 without OUD). Adverse childhood experiences influenced bonding only among those without OUD (p=0.004), while among those with OUD higher adversity scores were associated with less impaired bonding, though these findings were not significant. Given the small sample sizes and limited statistical power, future research should examine resilience factors that may contribute to oxytocin regulation, bonding, and potential translational interventions for high-risk populations.