Sex Differences in Stress-Induced Cortisol Response Among Infants of Mothers Exposed to Childhood Adversity

Background Adverse childhood experiences (ACEs) increase risk for mental illness in women and their children, and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis may play a role. The impact of ACEs on the HPA axis may be strongest when ACEs occur prepubertally and in those exposed to abuse ACEs. Methods To test this, we measured salivary cortisol in 96 mother-infant dyads while mothers were separated from their infant experiencing a laboratory stressor. Mothers completed the ACE questionnaire, ACEs occurring prepubertally (pACEs) were measured, and mother-infant dyads were grouped based on maternal pACE history: no pACEs, 1+ pACEs with abuse, or 1+ pACEs but no abuse. Results Mothers with 1+ pACEs exhibited decreases in cortisol (relative to pre-infant stressor), which differed significantly from the cortisol increase mothers with no pACEs experienced, regardless of abuse presence (p=.001) or absence (p=.002). These 1+ pACE groups did not differ from one another (p=.929). Significant sex differences in infant cortisol were observed in infants of mothers with 1+ pACEs (regardless of abuse) but not in infants of mothers with no pACEs. When mothers had 1+ pACEs, males showed decreases in cortisol in response to a stressor whereas females demonstrated increases, and males and females differed significantly when their mothers had 1+ pACEs with (p=0.025) and without (p=0.032) abuse. Conclusions Regardless of maternal exposure to childhood abuse, in response to a stressor, prepubertal ACEs were associated with lower cortisol response in mothers and sex differences in six-month-old infants, with males showing a lower cortisol response than females.