Dampening of adrenocortical responses during infancy: normative changes and individual differences.

Changes in cortisol and behavioral responses were examined longitudinally in 83 infants (39 girls, 44 boys) tested at their well-baby exams with inoculations at 2, 4, 6, and 15 months (72 infants completed all testing). Another sample of 2-, 4-, and 6-month-olds (n = 18 per age) received mock exams without inoculations to determine early developmental changes to the exam procedures. Behavioral distress was coded every 30 sec during the exam, a 5-min inoculation period, and a 20-min recovery period.

Stress reactivity and attachment security.

Seventy-three 18-month-olds were tested in the Ainsworth Strange Situation. These children were a subset of 83 infants tested at 2, 4, 6, and 15 months during their well-baby examinations with inoculations. Salivary cortisol, behavioral distress, and maternal responsiveness measures obtained during these clinic visits were examined in relation to attachment classifications.

Neonatal stress reactivity: predictions to later emotional temperament.

To investigate the relations among popular measures of neonatal stress and their link to subsequent temperament, 50 full-term newborns from a normal care nursery were examined responding to a heelstick blood draw. Baseline and heelstick measures of behavioral state, heart period, vagal tone, and salivary cortisol were obtained. Recovery measures of behavioral and cardiac activity were also analyzed.

Cortisol and behavioral responses to repeated stressors in the human newborn.

This manuscript reports on the effects of stressors repeated at a 24-hr interval on three samples of human newborns. In Study 1, newborns meeting criteria for obstetric and perinatal optimality experienced either 2 mock Discharge Exams, viewed as a type of handling stressor, or 2 Heelstick Blood Draws, viewed as a type of nocioceptive stressor. As in a previous study, newborns meeting optimality criteria showed habituation of the adrenocortical response to the repeated Discharge Exam.