What Do I Bring to the Team? Self‐Capacities Mediate the Association Between Childhood Interpersonal Trauma and Parenting Alliance in Couples

ABSTRACT Parents exposed to childhood interpersonal trauma are at risk of reporting difficulties following the birth of a child. Although parenting alliance is crucial for both parental and infant well‐being, it is often overlooked for trauma survivors in the postpartum period. More research is needed, focusing on both co‐parents and using a dyadic and longitudinal approach to understand the underlying mechanisms. Self‐capacities offer insights into trauma's effects at different life stages and might play a role in survivors' parenting alliance. Using a dyadic and longitudinal design, this study examined the possible mediating role of self‐capacities in the association between cumulative childhood interpersonal trauma (CCIT) and parenting alliance. A randomly selected sample of 923 couples who recently had a child, completed questionnaires on CCIT, self‐capacities disturbances (i.e., affect dysregulation, identity disturbance and interpersonal conflicts), and parenting alliance at two time‐points (T1, T2). Path analyses revealed that, when controlling for parenting alliance at T1, CCIT was associated with lower parenting alliance at T2 for both mothers and fathers, through interpersonal conflicts and affect dysregulation at T1. Precisely, a higher disposition to interpersonal conflicts mediated the link between one parent's CCIT and their own parenting alliance, while higher affect dysregulation mediated the link between one parent's CCIT and their co‐parent's parenting alliance. Findings suggest that CCIT survivors may struggle with parenting alliance through affect dysregulation and interpersonal conflicts during early postpartum, highlighting self‐capacities as both prevention and intervention targets to foster parenting alliance.