Infant adrenocortical reactivity and behavioral functioning: relation to early exposure to maternal intimate partner violence.

Prenatal stress negatively affects fetal development, which in turn may affect infant hypothalamic-pituitary-adrenal (HPA) axis regulation and behavioral functioning. We examined effects of exposure to a traumatic stressor in families [intimate partner violence (IPV)] on both infants' HPA axis reactivity to stress and their internalizing and externalizing behaviors. Infants (n = 182, 50% girls, x age = 11.77 months) were exposed to a laboratory challenge task designed to induce frustration and anger (i.e. arm restraint). Saliva samples were taken pre-task and 20 and 40 min post-task and then assayed for cortisol. Mothers reported on their pregnancy and postpartum IPV history, current mental health, substance use and their infants' behaviors. Structural equation modeling revealed that prenatal, but not postnatal, IPV was independently associated with infant cortisol reactivity and problem behavior. Maternal mental health predicted infant behavioral functioning but not infant HPA axis reactivity. These findings are consistent with the prenatal programing hypothesis; that is, early life stress affects later risk and vulnerability for altered physiological and behavioral regulation.