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Effect of multiple courses of antenatal corticosteroids on pituitary-adrenal function in preterm infants
1Department of Paediatrics Prince of Wales Hospital Chinese University of Hong Kong.
Insights
High antenatal dexamethasone doses in mothers did not cause severe pituitary-adrenal suppression in preterm infants. However, vigilance is needed for potential mild adrenal suppression and diminished adrenal reserve in these infants.
Area of Science:
- Neonatal Endocrinology
- Pediatric Pharmacology
- Maternal-Fetal Medicine
Background:
- Antenatal corticosteroids, like dexamethasone, are crucial for preterm infant lung maturation.
- Multiple courses of antenatal dexamethasone may raise concerns about potential long-term effects on infant endocrine function.
- The pituitary-adrenal axis is a critical system for stress response and overall infant health.
Purpose of the Study:
- To assess the pituitary-adrenal function in preterm infants exposed to multiple antenatal dexamethasone doses (≥8 doses).
- To determine if extensive antenatal dexamethasone impacts the infant's stress hormone response.
- To identify potential risks associated with high-dose antenatal dexamethasone exposure.
Main Methods:
- Utilized the human corticotrophin releasing hormone (hCRH) stimulation test in 14 preterm infants.
- Administered hCRH at 7 and 14 days of age, collecting blood samples at baseline and post-stimulation (15, 30, 60 min).
- Measured adrenocorticotrophic hormone (ACTH) and cortisol levels, comparing responses between time points and correlating with maternal dexamethasone dose.
Main Results:
- Baseline ACTH levels were higher at 14 days compared to 7 days (p=0.036).
- No significant differences in post-stimulation hormone levels were observed between 7 and 14 days.
- A negative correlation was found between maternal dexamethasone dose and infant serum cortisol at 15 and 30 min on day 14 (p<0.05).
Conclusions:
- The study suggests no severe pituitary-adrenal suppression in infants exposed to multiple antenatal dexamethasone courses.
- Evidence of mild adrenal suppression was noted in some infants, indicating a potential diminished adrenal reserve.
- Close monitoring of blood pressure, electrolytes, and signs of adrenal suppression is recommended for these infants.
Aim:
To evaluate the pituitary-adrenal function of preterm infants whose mothers received multiple courses (8 or more doses) of antenatal dexamethasone.
Methods:
The pituitary-adrenal function of 14 preterm infants whose mothers received eight or more doses of antenatal dexamethasone were assessed using the human corticotrophin releasing hormone (hCRH) stimulation test when 7 days (n = 14) and 14 days old (n = 12). During each test, blood samples were taken at 0 (baseline), 15, 30 and 60 minutes after an intravenous bolus dose of hCRH (1 microg/kg). The corresponding hormone concentrations were compared between days 7 and 14, and with various associated factors.
Results:
The baseline (0 min) plasma adrenocorticotrophic hormone concentration was significantly higher at day 14 than at day 7 (p = 0.036). None of the corresponding poststimulation (15, 30, and 60 min) hormone concentrations was significantly different between the two time epochs. When the association between the hormone concentrations and the number of antenatal dexamethasone doses received by the mothers was assessed, a significant negative correlation was observed in serum cortisol concentrations at 15 and 30 min on day 14 (r = -0.59, p = 0.04 and r = -0.60, p = 0.039, respectively).
Conclusions:
The absence of a significant difference in poststimulation hormone concentrations between days 7 and 14 in this cohort of infants, and the similarity of their hormone responses with those of older children and adults, suggests that no severe pituitary-adrenal suppression had occurred. None the less there was evidence of mild adrenal suppression in some of the treated infants. Vigilance in monitoring blood pressure, electrolytes and signs of adrenal suppression in infants whose mothers receive multiple courses (8 or more doses) of antenatal dexamethasone is required, as some of them might have diminished adrenal reserve.