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Effect of gestational age, postnatal age, and illness on plasma cortisol concentrations in premature infants
1Department of Pediatrics, Children's Hospital of New Mexico, University of New Mexico School of Medicine, Albuquerque 87123-5311.
Insights
Premature infants
Area of Science:
- Neonatal physiology
- Endocrinology
- Pediatric research
Background:
- Premature infants exhibit unique physiological responses.
- Understanding early life stress markers is crucial.
Purpose of the Study:
- To define postnatal plasma cortisol patterns in premature infants.
- To assess the impact of gestational and clinical factors on cortisol levels.
Main Methods:
- Measured plasma cortisol in 120 premature infants (24-36 wk gestation) on days 2, 4, and 6.
- Analyzed effects of gestational age, postnatal age, and illness severity.
- Examined morning and afternoon cortisol concentrations.
Main Results:
- Cortisol levels inversely correlated with gestational age; younger infants had higher levels.
- Illness negatively impacted cortisol; ventilatory support and surfactant use were associated with lower values.
- Postnatal cortisol patterns varied by gestational age, with significant decreases in infants ≤27 wk gestation.
Conclusions:
- Plasma cortisol concentrations in premature infants are linked to gestational age and illness markers.
- Gestational age and illness severity are key determinants of early postnatal cortisol patterns.
Abstract:
The purpose of this study was to define the pattern of postnatal plasma cortisol concentrations during the first week of life in premature infants, and to evaluate the effect of developmental and clinical factors on this pattern. We measured plasma cortisol concentrations in the morning and afternoon on d 2, 4, and 6 in 120 premature infants (gestational age 24-36 wk) and examined the effects of gestational age, postnatal age, and illness. We described an inverse relationship between gestational age and cortisol concentrations, with the youngest infants having the highest random cortisol values (F = 5.14, p = 0.0073). Illness had a significant negative effect such that the cofactors ventilatory support pattern (F = 6.62, p = 0.0016) or "use of surfactant" (F = 6.63, p = 0.001) defined a pattern where cortisol values were lower in infants that had the highest ventilatory requirements or that received surfactant compared with values from those infants who did not have these requirements. The postnatal pattern in cortisol values depended on gestational age. Ill infants more than 27 wk gestational age increased their cortisol values from d 2 to d 6 although cortisol values decreased in well infants. These patterns resulted in a nonsignificant change over time for these age groups. In contrast, cortisol values significantly decreased from d 2 to d 6 in both well and ill infants that were less than or equal to 27 wk. We conclude that plasma cortisol concentrations in the premature infant are significantly correlated with gestational age and to markers of illness.(ABSTRACT TRUNCATED AT 250 WORDS)