Methodologic issues in the measurement of oxytocin in human neonates

Oxytocin's (OT) role in the onset and maintenance of labor and in the letdown reflex is well known. OT also has been recognized as a neurotransmitter having functions in the central nervous system, including an influence on behavior (e.g., initiation of maternal behavior). This research was conducted to (1) evaluate whether human tactile contact in the human newborn would increase urine OT levels and alter infant behavioral state, and (2) determine the reliability of measuring OT in human infant urine. Although the data did not support the hypotheses, it was noted that OT levels significantly decreased in infants who cried during the study period and that there was no correlation between infant's chronologic age and OT levels. The findings illustrate several methodologic and measurement problems in the study of OT in human infants and that urine sampling in the neonate is not the most reliable method to evaluate change in OT levels. Some general issues concerning research with human infants also are discussed. Further research is recommended to document baseline levels of OT in neonates and to explore the use of salivary OT to measure short-term responses to interventions.