Feeding-Induced Cortisol Response in Newborn Infants

Area of Science:

• Neonatal physiology
• Endocrinology
• Stress response

Background:

• Understanding biological rhythms and stress response in sick newborns is crucial for minimizing intensive care effects.
• Salivary cortisol is a noninvasive marker for adrenal function, but its control variables require further investigation.

Purpose of the Study:

• To investigate the presence of a feeding-induced cortisol response in newborns.
• To identify control variables influencing this cortisol response.

Main Methods:

• Fifty-three newborns (30–40 weeks corrected age) on regular oral/enteral feeding were studied.
• Saliva samples collected pre- and post-feeding.
• Generalized estimating equations used to assess cortisol levels and feeding-related elevation against clinical variables.

Main Results:

• Higher cortisol levels observed in infants ≥37 weeks corrected age and post-feeding (P < 0.001).
• Oral feeding elicited a greater cortisol response than enteral feeding (P = 0.034).
• Prolonged feeding (≥30 min) reduced cortisol response compared to brief feeding (<30 min) (P < 0.001).

Conclusions:

• A feeding-induced cortisol response exists in newborns.
• This response is more pronounced with oral feeding and diminished by prolonged feeding duration.
• Further research could explore the role of this response in developing adrenal rhythms.