New research published in the Annals of Neurology

Preterm babies who've had more skin-breaking medical procedures have slower brain development as they grow to their due dates, shows new research published this week in the Annals of Neurology.


Skin-breaking procedures such as needles, IVs and feeding tubes are critical for providing life-saving hospital care that allows premature babies to grow and survive. While much research has reported on infant physiological responses to pain such as changes in the brain’s electrical activity and blood flow, heart rate, hormone levels, and behaviours like hand movements and facial expressions, this study uses advanced brain imaging techniques to measure the relationship of painful procedures on infant brain development.

The researchers used MRI (magnetic resonance imaging) to take brain scans of 86 preterm babies within the first few weeks of life and then a few months later near their due dates. Each infant had between 69 to 179 skin-breaking procedures while hospitalized.

The MRI scans allowed researchers to evaluate the infants' brain development by measuring a molecule called n-acetylaspartic acid (NAA), which increases as brain cells mature, and by assessing the rate of water movement within the brain, which becomes more organized as the brain develops. Statistical analysis accounted for factors such as infection, illness severity, surgery, and pain medication.

The researchers found that babies who had more skin-breaking procedures had lower NAA levels and less organized water movement, which revealed impaired brain development. These differences were widespread throughout the brain.

“Preterm babies are exposed to stressful, life-saving hospital care during a period of complex brain development,” says Dr. Ruth Grunau, the study co-author. Dr. Grunau, a psychologist, is a senior scientist at the Child & Family Research Institute (CFRI) at BC Children's Hospital and professor in the Division of Neonatology, Department of Pediatrics, at the University of British Columbia (UBC). “They're more sensitive to touch and pain at a time when their physiological systems are not ready to handle stress outside the womb.”

“We now have ways to safely measure brain development in critically ill and young babies,” says Dr. Steven Miller, the study co-author. Dr. Miller is a CFRI senior clinician scientist, neurologist at BC Children’s Hospital, associate professor in the Division of Neurology, UBC Department of Pediatrics, and holds the Canada Research Chair in Neonatal Neuroscience. “We have tools to measure the impact of the baby's experience on the brain from early times in the baby's life.”

Dr. Grunau's previous research showed that babies who've had more painful procedures are more likely to have poor developmental outcomes in terms of their stress response, motor and cognitive skills. She has also developed ways to measure the pain-related stress that newborns experience. Dr. Miller’s work is focused on baby’s experience with illness and he has previously shown that infection precedes abnormal brain development in preterm infants.

The researchers say the next step in the research is to understand how these brain changes will affect the children’s thinking, motor control, and language development.

This research was funded by the Canadian Institutes of Health Research. The infants were patients of the Neonatal Intensive Care Unit at BC Women’s Hospital & Health Centre, an agency of the Provincial Health Services Authority (PHSA).