The effects of birth condition on infants' cortisol response to stress
Ramsay, D.S.; Lewis, M.
Pediatrics 95(4): 546-549
1995
ISSN/ISBN: 0031-4005 PMID: 7700756 Document Number: 449987
Objective, design, and subjects: To examine the effects of nonoptimal birth condition on cortisol response to routine inoculation in a longitudinal sample of full-term healthy infants at 2, 4, and 6 months of age. Measurement and main results: Optimal versus nonoptimal birth condition was defined by a large versus small head circumference and a high versus low 1-minute Apgar score. An optimal birth condition was associated with a high cortisol response at 2 months, but a low cortisol response by 6 months of age. Conclusions: The findings indicate a reversal in the meaning of high adrenocortical reactivity between 2 and 6 months of age: high cortisol response may index optimal functioning at 2 months, but nonoptimal functioning by 6 months of age. Together with other results, this reversal provides evidence for a developmental shift in adrenocortical functioning during this period. The findings also show that the effects of a nonoptimal birth condition in otherwise healthy full-term infants persist for at least the first 6 months of life.