ABSTRACT
INTRODUCTION: Prenatal exposure to supraphysiological glucocorticoid (GC) levels may lead to long-lasting developmental changes in numerous biological systems. Our prior study identified an association between prenatal GC prophylaxis and reduced cognitive performance, electrocortical changes, and altered autonomic nervous system (ANS) activity in children aged 8-9 years. This follow-up study aimed to examine whether these findings persisted into adolescence. MATERIAL AND METHODS: Prospective observational follow-up study involving twenty-one 14- to 15-year-old adolescents born to mothers who received betamethasone for induction of fetal lung maturation in threatened preterm birth, but who were born with a normal weight appropriate for their gestational age (median 37+4 gestational weeks). Thirty-five children not exposed to betamethasone served as the reference group (median 37+6 gestational weeks). The primary endpoint was cognitive performance, measured by intelligence quotient (IQ). Key secondary endpoints included symptoms of attention-deficit/hyperactivity disorder (ADHD) and metabolic markers. Additionally, we determined electrocortical (electroencephalogram), hypothalamus-pituitary-adrenal axis (HPAA), and ANS activity in response to a standardized stress paradigm. RESULTS: No statistically significant group difference was observed in global IQ (adjusted mean: betamethasone 103.9 versus references 105.9, mean difference -2.0, 95% confidence interval [CI]: -7.12 to 3.12, p = 0.44). Similarly, ADHD symptoms, metabolic markers, the overall and stress-induced activity of the HPAA and the ANS did not differ significantly between groups. However, the betamethasone group exhibited reduced electrocortical activity in the frontal brain region (spectral edge frequency-adjusted means: 16.0 Hz versus 17.8 Hz, mean difference -1.83 Hz, 95% CI: -3.21 to -0.45, p = 0.01). CONCLUSIONS: In 14- to 15-year-old adolescents, prenatal GC exposure was not associated with differences in IQ scores or ANS activity compared to unexposed controls. However, decelerated electrocortical activity in the frontal region potentially reflects disturbances in the maturation of cortical and/or subcortical brain structures. The clinical significance of these changes remains unknown. Given the small sample size, selective participation/loss of follow-up and potential residual confounding, these findings should be interpreted cautiously. Further research is required to replicate these results in larger cohorts before drawing firm clinical conclusions.
ABSTRACT
INTRODUCTION: Glucocorticoid (GC) -induced fetal programming of the activity of the hypothalamus-pituitary-adrenal axis (HPAA) and its associated cognitive and behavioral consequences in later life have been well characterized in several animal species. However, information on humans is scarce. In this study, we examined HPAA activity markers and associated outcomes at 8 to 9 years of age among children prenatally exposed to GC for suspected preterm birth. Our hypothesis was that antenatal exposure to the betamethasone (BM) is associated with exacerbation of HPAA activity in childhood. MATERIAL AND METHODS: Prospective observational study in 31 children whose mothers received single (n = 19) or multiple (n = 12) courses of BM for threatened preterm birth but born with normal weight appropriate for the gestational age (median 37+6 weeks of gestation) compared with 38 non-exposed, age-matched children. Primary end point was the activity of the HPAA in response to the Trier Social Stress Test. Secondary end points were changes in autonomic nervous system (ANS) activity, cognitive performance (IQ), attention-deficit/hyperactivity disorder (ADHD) symptoms, and electrocortical activity (EEG). RESULTS: There was no statistically significant difference in HPAA activity markers between antenatal BM exposed and unexposed groups. ANS activity in BM-exposed children shifted towards a higher parasympathetic tone reflected by a higher overall high-frequency band power of heart rate variability. IQ scores were within normal limits for both groups; however, BM-exposed children had lower IQ scores than the unexposed group. BM-exposed group had marginally more ADHD core symptoms and increased electrocortical activity in the occipital brain region compared with controls. A monotonic dose-response relation between BM exposure and activity of the ANS and IQ was estimated in post-hoc analyses. CONCLUSIONS: Antenatal exposure to BM in the context of threatened preterm birth was not associated with changes in HPAA activity in childhood. However, BM exposure may be associated with changes in ANS activity. Antenatal GC prophylaxis is a valuable and often life-saving therapy, but its prescription may warrant a well-balanced risk-benefit assessment.
