336 - Early Postnatal Steroids and Corpus Callosum Microstructure in Extremely Preterm Born Infants

Poster Number: 336
Publication Number: 336.442

Sarah Dubner, Stanford University, SANTA CRUZ, CA, United States; Lucy E. Rickerich, Stanford University, York, ME, United States; Melissa Scala, Stanford University School of Medicine, San Francisco, CA, United States; Lisa Bruckert, Stanford University School of Medicine, Stanford, CA, United States; Heidi M. Feldman, Stanford University School of Medicine, Palo Alto, CA, United States; Katherine E. Travis, Stanford University School of Medicine, Stanford, CA, United States

Background: Early postnatal steroid administration is a strategy to prevent or reduce severity of bronchopulmonary dysplasia (BPD) in extremely preterm born infants (EPT, < 28 weeks). Steroids’ effects on the brain depend on type, dose, timing, and duration of treatment. The PREMILOC protocol provided low dose hydrocortisone for the first 10 days of life to decrease BPD. The effect of the protocol on structural brain connectivity has not been evaluated.

Objective: This study assessed variation in connectivity metrics of the corpus callosum at near-term gestational age in two groups: EPT infants with or without early postnatal hydrocortisone per the PREMILOC protocol.

Design/Methods: Design: Retrospective cohort study of postnatal steroids and structural brain connectivity
Participants: Infants born < 28 weeks gestation at Lucile Packard Children’s Hospital at Stanford who had near-term diffusion MRI (dMRI) as part of routine clinical care.
Procedures: We assessed dMRI mean fractional anisotropy (FA) and mean diffusivity (MD) across 7 segments of the corpus callosum.
Data Analysis: Multivariable linear regressions assessed variation in FA or MD based on PREMILOC protocol:  Early Steroids, ES=0.5mg/kg twice per day for 7 days, followed by 0.5 mg/kg per day for 3 days (n=31) versus No Steroids, NS (n=21). Models covaried for post-menstrual age at scan and an index of medical risk composed of 7 common postnatal medical complications.

Results: No group differences were found in gestational age (NS = 26.5 ± 1.1, ES = 26.7 ± 0.8, t = -1.0, p = 0.30).  ES postmenstrual age at scan was lower than NS (NS = 37.6 ± 1.7 wks, ES = 36.6 ± 1.0 wks, t=2.5, p=0.02). No group differences were found in total number of medical complications (NS = 1.3 ± 1.0, ES = 1.4 ± 1.1, t = -0.34, p=0.70). In particular, no group differences were found in number with BPD (needing O2 at 36 weeks, NS=3, ES=6, p=0.72) or necrotizing enterocolitis (NEC, NS=5, ES=4, p=0.46). No significant associations between steroid exposure and mean FA or mean MD were found in any segment of the corpus callosum. Conclusion(s): Early, low dose, postnatal hydrocortisone was not associated with clinical improvements or significant differences in corpus callosum white matter microstructure at near term gestational age. Future investigations will assess other white matter pathways in regions previously reported to be affected by steroid exposure (e.g., cerebellum).