Maternal experiences of trauma and hair cortisol in early childhood in a prospective cohort

Abstract

Background and objective: Maternal trauma can have intergenerational consequences but little is known about whether maternal traumas affect key biological domains associated with mental health in their offspring. The objective of this study was to examine maternal lifetime history of traumatic events through mid-gestation in relation to offspring cortisol production in early childhood.

Methods: The sample was comprised of 660 children (49.9% Black, 44.4% White) from a longitudinal study of mother-offspring dyads in Shelby County, Tennessee, followed from mid-gestation to child age 4 years (enrolled 2006-2011). Maternal lifetime history of traumatic life events were assessed mid-gestation using the Traumatic Life Events Questionnaire. Total cortisol output among offspring was measured using hair cortisol concentrations at ages 1 to 4 years.

Results: Associations of maternal trauma history with child hair cortisol varied by child's age. No association was observed at age 1 or 2. In adjusted regression models, at ages 3 and 4, offspring of mothers in the third (β = 0.99, P < .01), fourth (β=0.72, P < .05), and fifth (β=0.83, P < .01) quintiles of trauma exposure history had elevated (natural log) hair cortisol concentrations, relative to mothers in the lowest quintile (P-trend = 0.003). The associations were not attenuated after adjustment for theorized pathways, including premature birth, maternal postpartum depression, and maternal parenting stress.

Conclusions: Maternal lifetime trauma exposures are associated with offspring hair cortisol concentrations. Future research is needed to determine intermediary mechanisms and functional significance of elevated hair cortisol concentration in young children.

Keywords: Children; Cortisol; HPA axis; Hair; Mother; Stress; Trauma.