In Australia approximately 9% of babies are born preterm (less than 37 weeks gestation), and there is compelling evidence that the effects of preterm birth persist over life. Babies born preterm often face life-long setbacks in development and education and may be prone to continuing health challenges. Dr Luke Schneider, a Postdoctoral Research Officer at the Robinson Research Institute recently completed a study that advances this area of research – and his results were surprising. He found that as long as the preterm child experiences no brain injury in early life, their cognitive ability as teenagers can be as good as term-born peers – depending on the quality of their early-life home environment.
Individuals born preterm are more likely to require special education at school, less likely to complete a university degree and, on average, receive a lower income than their term born peers. These adverse outcomes may be associated with altered brain development after preterm birth. Such abnormalities may be microstructural and not readily detected with standard imaging.
“Brain lesions occur in less than 10% of children born before 32 weeks gestation, and these are the individuals that seem to demonstrate the greatest difficulties. However, this highlights that there is something else about preterm birth that is disadvantaging those individuals without lesions,” explained Luke.
Together with senior researcher Dr Julia Pitcher, Luke assessed the cognitive abilities of 145 preterm and term born young people aged approximately 12 years. He assessed data on social disadvantage at the time of birth and the time of the cognitive assessment.
“The results of our study were surprising. We found that once children reach the age of 12, being born preterm didn’t really influence cognitive performance”, said Luke.
“What was more important was the early home environment or socioeconomic condition the children lived in after coming home from hospital. Additionally, the child’s height at the time of the assessment, and their length and head circumference at the time of birth, predicted their cognitive performance. These factors point to the importance of postnatal growth, and presumably nutrition in early childhood, to cognitive development.”
To assess socioeconomic status at time of birth and during the study, Luke examined census data to calculate the SEIFA scores (Socio-Economic Indexes for Areas). He discovered that greater social disadvantage at the time of birth (ie lower socioeconomic status) was associated with decreased cognitive performance in these young people.
“We found the SEIFA score at the time of the study was not related to cognitive performance. It was only the score at birth that was important. This may reflect a critical developmental period in infancy and early childhood.”
The next step is uncovering the specific factors associated with lower socioeconomic status that are affecting neurological development, so these can be tackled to improve the chances of children born too soon.
“What we don’t know yet is how different factors in the home environment drive specific aspects of brain development. We believe early nutrition and enrichment through physical and intellectual stimulation are likely to have key roles”, explained Dr Julia Pitcher.
While these research findings add to the growing body of research in this area there is still much yet to be explored.
“The overarching goal of our research is to understand the long-term influences of preterm birth on cognitive development. We have a number of projects underway that aim to discover the neurological mechanisms that underpin cognitive deficits after preterm birth, identify which specific aspects of cognition might be more susceptible to perturbation after preterm birth, and identify other potentially modifiable factors that might have an impact on cognitive development,” said Luke.
“Our research focus is unique to others in this area as we include young people from all preterm birth categories not just the very preterm, focus on adolescents as opposed to young children, and we exclude those with any neurological injury,” said Luke.
The results are promising for parents of preterm born children.
“If we can develop effective interventions which can support or improve cognitive development in early life, this will lead to a huge economic benefit through reduced need for special education services, plus improve the quality of life for the individual and their families.”
Luke and Julia’s paper was published in the 165th edition of the Journal of Pediatrics (2014, 165(1), pp. 170-177).