Impact of antenatal glucocorticoid exposure on the activity of the stress system, cognition and behavior in 8 to 9-year-old children: a clinical cohort study

Objective: To determine stress-sensitivity and neurodevelopmental outcome in 8- to 9-year-old children following antenatal exposure to glucocorticoid (GC) prophylaxis for neonatal respiratory distress syndrome. Design: Clinical cohort study. Setting: University-based obstetric clinic in Central Germany. Population: 31 term or near-term born children whose mothers received single or multiple courses of betamethasone (BM) to induce fetal lung maturation in threatened preterm birth compared to 39 non-exposed children. Methods: Multi-system assessment of the individual stress response together with an analysis of cognitive, behavioral and electrocortical functioning. Main Outcome Measures: Activity of the hypothalamus-pituitary-adrenal axis (HPAA, primary outcome domain) and the autonomic nervous system (ANS, secondary outcome domain) including markers of heart rate variability (HRV). Additional endpoints were the cognitive performance (IQ) and attention-deficit/hyperactivity disorder (ADHD) core symptoms. Results: HPAA activity was not affected by antenatal GC-exposure. ANS activity in GC-exposed children shifted towards a higher parasympathetic tone reflected by a higher overall high-frequency band power of HRV (1313 vs. 762 msec2/Hz, p=0.03). BM-exposed children had lower cognitive performance (IQ 96.9 vs. 108.0, p<0.01) and a marginally higher ADHD score (FBB-ADHD scale 5.5 vs. 4.6 points, p=0.04). A monotonic dose-response relationship between GC-exposure and stress-induced activity of the ANS and IQ was estimated post-hoc. Conclusions: Antenatal exposure to supraphysiological concentrations of BM in the context of threatened preterm birth was associated with multidimensional changes in stress-sensitivity and neurodevelopment in later life. As these changes may be dose-dependent, antenatal GC prophylaxis should be used at the minimum effective dose after a careful risk-benefit assessment.