Premature infants exposed to steroid medications after birth are at increased risk for impaired brain development, shows a new study co-authored by investigators at the Child & Family Research Institute at BC Children’s Hospital and the University of California San Francisco (UCSF). The study was published in the October 19, 2011 issue of Science Translational Medicine.
Using high-tech MRI scans, researchers measured the brain volume of 172 babies born at 32 weeks of pregnancy or earlier. 115 of those babies were at BC Children’s. They measured each baby’s cerebellum shortly after birth and again when they reached full term (when they should have been born). The cerebellum is the part of the brain associated with balance, motor learning, language and behaviour.
Investigators found that premature babies given hydrocortisone or dexamethasone had cerebellar volumes that were, on average, 10 per cent smaller by term age than premature babies who did not receive the medications. Hydrocortisone and dexamethasone are among a class of steroids called glucocorticoids that are used to support lung maturation, normalization of blood pressure, and breathing. Unfortunately, good alternatives to these medicines do not yet exist.
They also examined babies who were exposed to a glucocorticoid called betamethasone typically given to women in preterm labour to hasten the baby’s lung development while in the womb. They found the medications had no impact on brain development in this group of infants.
From here, researchers plan to investigate the long-term impact of early impaired brain development by following up with the newborns involved in the study with detailed neurological examinations and developmental testing from infancy to school age through the Neonatal Follow-Up Clinic.
Dr. Steven Miller was the senior author of this study and led the research at BC Children’s. Dr. Miller is a CFRI senior clinician scientist, neurologist at BC Children’s, and associate professor with UBC's Department of Pediatrics. Study co-authors included:
- Dr. Vann Chau, CFRI clinician scientist, BC Children’s neurologist and clinical assistant professor, UBC Department of Pediatrics
- Dr. Ken Poskitt, CFRI clinician scientist, BC Children’s pediatric neuroradiologist and assistant professor, UBC Department of Pediatrics
- Dr. Ruth Grunau, CFRI senior scientist, professor with UBC Department of Pediatrics and associate member, UBC Department of Psychology
The first author was Dr. Emily Tam, child neurologist in the Neurological Intensive Care Nursery at the UCSF Benioff Children's Hospital, and close collaborator with the UBC team.
This research was made possible through the support and dedication of research staff at BC Children’s, including Sandy Belanger, Research Nurse; Mark Chalmers, Research Respiratory Therapist; Janet Rigney, Research Assistant; and Meisan Brownlum, Research Assistant. Wendy Krishnaswamy, a Registered Nurse in the Pediatric Intensive Care Unit, was involved in the study during the early stages and was critical to its implementation.
[research article] [Globe and Mail story] [UCSF media release]