Release of Oxytocin and Cortisol Is Associated With Neurobehavioral Patterns in Premature Infants

Objective: To examine relationships among salivary oxytocin and cortisol levels in parents and preterm infants and neurobehavioral functioning in preterm infants after skin-to-skin contact. Design: A secondary analysis of a randomized crossover study. Setting: NICU. Participants: Twenty-eight stable premature infants and their mothers and fathers. Methods: Participating infants contributed 108 saliva samples that we collected 45 minutes after skin-to-skin contact and tested for oxytocin and cortisol. We randomized data collection by whether the infant was held first by the mother or by the father. We conducted linear regression to test if summary scores on the NICU Network Neurobehavioral Scale were associated with salivary oxytocin and cortisol levels. Results: We found a significant negative relationship between infant oxytocin levels and the Stress scores (b = –0.07, p <.01) and the Excitability scores (b = –1.12, p =.04) among infants held skin-to-skin with their mothers. We found a significant positive relationship between infant oxytocin levels and the Self-Regulatory scores (b = 0.38, p =.05) among infants held skin-to-skin with their mothers. We found a significant positive relationship between infant cortisol level and the Stress scores (b = 0.05, p =.04), Excitability scores (b = 1.06, p = 0.05), and Asymmetrical Reflexes scores (b = 1.21, p =.03) among infants held skin-to-skin with their mothers. We only found a negative significant relationship between infant cortisol levels and the Stress scores (b = –0.03, p =.04) among infants held skin-to-skin with their fathers. Conclusion: We found that oxytocin is an important biomarker that may improve infant neurobehavioral functioning. The data showed a difference in oxytocin responses after skin-to-skin contact with mothers compared to fathers.