CORTISOL AND BEHAVIORAL-RESPONSES TO STRESS IN NEWBORN-INFANTS

Five-day-old infants' responses to stress while being heelstuck were e xamined. Behavioral responses as well as the adrenocortical responses of cortisol release were used as measures of manifest and internal str ess response. We divided 67 infants into two groups-those who presente d no sounds during the ''heelstick'' (C group) and those to whom heart beat sounds were presented during the ''heelstick'' (E group). Heartbe at sounds were presented to infants at 85 dB. The C group showed more reactive adrenocortisol release and more behavioral responses than the E group. We found the calming effect of heartbeat sounds on stress in newborn infants.