The Effects of a Pacifying Stimulus on Behavioral and Adrenocortical Responses to Circumcision in the Newborn

Eighteen, healthy male newborns, 2–5 days old, were subjects in this study of the effects of a pacifier on the newborn's behavioral and adrenocortical responses to circumcision. Half of the subjects were randomly assigned to a condition in which they were encouraged to suck on a pacifier during circumcision, while half served in a no pacifier, control condition. Behavioral observations were made for 1/2 hour before, during, and after circumcision; while blood samples for serum cortisol determination were obtained immediately before circumcision and 30 min later. The results showed that stimulating the newborn with the pacifier reduced crying by about 40%. Reducing crying, however, had no significant effect on the adrenocortical response. Elevations of serum cortisol predicted average behavioral state following circumcision, whereas crying during circumcision did not. Furthermore, there was evidence that the neonatal adrenocortical system was sensitive to variations in surgical procedures. The results indicate the importance of obtaining data on both behavioral and hormonal systems in studies of stress and coping in human newborns.