Early, low-dose hydrocortisone and near-term brain connectivity in extremely preterm infants

ABSTRACT Background Postnatal steroids are used to prevent bronchopulmonary dysplasia in extremely preterm infants but may have adverse effects on brain development. This study assessed variation in connectivity metrics of major white matter pathways in the cerebrum and cerebellum at near-term gestational age among infants who did or did not receive a standardized regimen of hydrocortisone during the first 10 days of life. Methods Retrospective cohort study. Participants: Infants born < 28 weeks, divided into 2 groups: Protocol group (n=33) received at least 50% of and not more than 150% of an intended standard dose of 0.5mg/kg hydrocortisone twice daily for 7 days, then 0.5 mg/kg per day for 3 days; versus Non-Protocol group (n=22), that did not receive protocol hydrocortisone or completed <50% of the protocol dose. We assessed group differences in near-term diffusion MRI mean fractional anisotropy (FA) and mean diffusivity (MD) across the corticospinal tract, inferior longitudinal fasciculus, corpus callosum and superior cerebellar peduncle. Results Groups were comparable in terms of gestational age, post-menstrual age at scan, medical complications, bronchopulmonary dysplasia, and necrotizing enterocolitis. No significant large-effect group differences were identified in mean FA or MD in any cerebral or cerebellar tract between the two groups. Conclusion(s) Low dose, early, postnatal hydrocortisone was not associated with significant differences in white matter tract microstructure at near term gestational age. Impact This study compared brain microstructural connectivity as a primary outcome among extremely preterm infants who did or did not receive early postnatal hydrocortisone. Low dose hydrocortisone in the first 10 days of life was not associated with significant differences in white matter microstructure in major cerebral and cerebellar pathways Hydrocortisone did not have a significant effect on early brain white matter circuits.