Developmental change in infant cortisol and behavioral response to inoculation

Area of Science:

• Pediatric medicine
• Developmental psychology
• Endocrinology

Background:

• Infant responses to medical procedures like inoculations are crucial for understanding stress and development.
• Cortisol levels and behavioral reactions are key indicators of physiological stress in infants.

Purpose of the Study:

• To investigate the developmental changes in infant cortisol and behavioral responses to inoculations at 2 and 6 months of age.
• To compare infant responses to 1 versus 2 inoculations during a single pediatric visit.

Main Methods:

• Observational study tracking cortisol levels (pre- and post-inoculation) and behavioral responses (e.g., quieting time).
• Participants included infants at 2 and 6 months of age receiving either one or two inoculations.
• Analysis focused on cortisol level, cortisol response, and behavioral measures in relation to age and inoculation number.

Main Results:

• Cortisol levels decreased with age, while the overall cortisol response did not significantly vary with age.
• For infants exhibiting a cortisol increase, both cortisol level and response decreased with age.
• Older infants (6 months) quieted faster post-inoculation compared to younger infants (2 months).
• A moderate correlation was found between quieting behavior and cortisol response in infants showing a cortisol increase.

Conclusions:

• A developmental decline in adrenocortical reactivity to inoculations is evident in infants who exhibit a cortisol release.
• Infant stress responses to inoculations mature over the first six months of life.
• The number of inoculations (1 vs. 2) did not significantly alter these age-related response patterns.