Abstract
We examined the association between prenatal exposure to cigarettes and adrenocortical responses to stress in 7βmonthβold infants. Cortisol levels were assessed twice prior to and twice following affectβeliciting procedures in 111 (59 exposed and 52 nonexposed) infants. Cortisol reactivity was defined as the difference between the peak poststressor cortisol level and the pretask cortisol level. Higher values indicated higher cortisol reactivity. Exposed infants had higher peak cortisol reactivity than nonexposed infants. There were no differences in pretask cortisol levels. Maternal hostility mediated the association between cigarette exposure and peak cortisol reactivity. Furthermore, infant gender moderated this association such that exposed boys had significantly higher peak cortisol reactivity than nonexposed infants or exposed girls. These findings provide additional evidence that prenatal cigarette exposure is associated with dysregulation during infancy and that early adverse, nonsocial experiences may have relatively longβlasting effects on cortisol reactivity in infants. Β© 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 819β834, 2008