A history of childhood trauma is associated with increased risk for psychopathology and interpersonal difficulties in adulthood and, for those who have children, impairments in parenting and increased risk of negative outcomes in offspring. Physiological and behavioral mechanisms are poorly understood. In the current study, maternal history of childhood trauma was hypothesized to predict differences in maternal affect and HPA axis functioning. Mother-infant dyads (N = 255) were assessed at 6 months postpartum. Mothers were videotaped during a 3-min naturalistic interaction, and their behavior was coded for positive, neutral, and negative affect. Maternal salivary cortisol was measured six times across the study visit, which also included an infant stressor paradigm. Results showed that childhood trauma history predicted increased neutral affect and decreased mean cortisol in the mothers and that cortisol mediated the association between trauma history and maternal affect. Maternal depression was not associated with affective measures or cortisol. Results suggest that early childhood trauma may disrupt the development of the HPA axis, which in turn impairs affective expression during mother-infant interactions in postpartum women. Interventions aimed at treating psychiatric illness in postpartum women may benefit from specific components to assess and treat trauma-related symptoms and prevent secondary effects on parenting.
Keywords: Cortisol; Early-life trauma; HPA axis; Maternal affect; Parenting behavior; Post-traumatic stress disorder; Trauma.