Antenatal Steroid Exposure and Heart Rate Variability in Adolescents Born With Very Low Birth Weight

BACKGROUND: Reduced heart rate variability (HRV) suggests autonomic imbalance in the control of heart rate and is associated with unfavorable cardiometabolic outcomes. We examined whether antenatal corticosteroid (ANCS) exposure had long-term programming effects on heart rate variability (HRV) in adolescents born with very low birth weight (VLBW). METHODS: Follow-up study of a cohort of VLBW 14 year-olds born between 1992 and 1996 with 50% exposed to ANCS. HRV in both the time and frequency domains using Nevrokard Software was determined from a 5 minute electrocardiogram tracing. RESULTS: HRV data from 89 (35 male, 53 non-black) exposed (ANCS+) and 77 (28 male, 29 non-black) unexposed (ANCS−) adolescents were analyzed. HRV did not differ between ANCS+ and ANCS− black participants. However, in non-black participants, a significant interaction between ANCS and sex was observed, with ANCS− females having significantly greater HRV than ANCS+ females and males, and ANCS− males for both time and frequency domain variables. CONCLUSIONS: Among non-black adolescents born with VLBW, ANCS exposure is associated with reduced HRV with apparent sex-specificity. Reduced HRV has been associated with development of adverse cardiometabolic outcomes, thus supporting the need to monitor these outcomes in VLBW adolescents as they mature.