Interpersonal violence against women is a major global health problem that may have intergenerational effects. This study investigated associations between maternal experiences of interpersonal violence and other traumatic events and maternal and infant salivary diurnal cortisol in a cohort of adolescent mothers in São Paulo, Brazil.
Adolescent mothers (14–19 years) participating in a home-visiting intervention were interviewed retrospectively about lifetime and pregnancy violence and trauma exposure. Mothers collected saliva at waking and before bedtime from themselves (n = 23) and their infants (n = 32) at 12 months postpartum. Multivariable regression models were used to examine associations between trauma history variables and salivary diurnal cortisol.
Adjusting for the intervention group, infant sex, maternal age, non-supplement medication use, and sample collection time, we found that higher-than-average lifetime trauma exposure was associated with maternal evening cortisol (b = 0.472, p-value = 0.028). Lifetime assaultive violence exposure was also associated with maternal evening cortisol (b = 0.196, p-value = 0.02). Maternal exposure to traumatic events in pregnancy was positively associated with bedtime cortisol levels of infants (b = 0.21, p = 0.01). Trauma variables were not associated with maternal or infant morning cortisol levels.
Results suggest that maternal trauma history influences both maternal and infant postnatal cortisol regulation as indexed by evening cortisol levels. These results are consistent with models of fetal programming; however, future studies should investigate potential postnatal psychobiological pathways. Lifetime trauma exposure may also become embedded in the maternal hypothalamic–adrenal–pituitary axis regulation. Future studies are needed to consider other biological pathways in the intergenerational transmission of trauma.