The relationship of predominant behavioral state and salivary cortisol in the human neonate

The relationship of predominant behavioral state to levels of salivary cortisol in the newborn infant was examined. A sample of 99 healthy newborns were dichotomized into groups representing characteristic predominant state following multiple observations of state behavior. Group A (state predominance sleep) babies had a mean salivary cortisol level of 1.18 micrograms per deciliter (micrograms/dl) and Group B (state predominance awake) babies had a mean salivary cortisol level of 0.83 micrograms/dl. Analysis of variance revealed a statistically significant difference in cortisol levels between the predominance of state groups; however, the direction of the difference did not conform to the expected pattern. The role of state predominance in infant research and the unexpected directions of the cortisol levels are explored. Obtaining small samples of saliva for the measurement of cortisol was demonstrated to be an easy and unobtrusive means of studying adrenal response. Categorization of infants into state predominance groups promises to provide continued research direction as it evolves into a clinically useful tool for nursing practice.