While most babies born more than two months prematurely now survive thanks to medical advances, little progress has been made in the past two decades in preventing associated developmental problems, an expert review has found.
The review also found that very preterm babies can have their brain development disrupted by environmental factors in the neonatal intensive care unit (NICU), including nutrition, pain, stress and parenting behaviours.
Each week in Australia more than 50 babies are born very preterm – at fewer than 32 weeks’ gestation – increasing their risk of disrupted brain development. Many of these infants have no or mild issues but some experience developmental delays, deafness, blindness, cerebral palsy and behavioural issues.
A review conducted by experts from the Children’s Hospital of Orange County in the US and the Turner Institute for Brain and Mental Health at Monash University in Australia found that while these neurodevelopmental problems can be related to brain injury during gestation or due to cardiac and respiratory issues in the first week of life, the environment of the NICU is also critical.
Published on Thursday in the New England Journal of Medicine (NEJM), the review examined research that used brain magnetic resonance imaging (MRI) shortly after birth, including new insights from advanced neuroimaging techniques as well as studies of infant nervous systems.
“Over the past two decades, the incidence of cerebral palsy, particularly severe cerebral palsy, has declined,” the review found. “However, there has been no decline in the high incidence of cognitive impairment and social and emotional challenges among children and young adults born preterm.”
Dr Peter Anderson, a co-author of the paper and professor of paediatric neuropsychology at Monash University, said the review sought to better understand why some children born very early experience significant problems while others experience none.
“This particular period in their third trimester of pregnancy is well known to be a period where there is an enormous development in the brain … probably the most dynamic and rapid period of development in the brain throughout the lifespan,” Anderson said.
An injury during this period can alter the normal brain development processes . But the review found that even if the infant has no injury to the brain, development can be affected by environmental factors after birth.
“They’re experiencing enormous levels of stress as a result of a whole range of different factors, including loud noises and lights, which they wouldn’t be being exposed to in utero,” Anderson said.
To improve outcomes for very preterm babies, the review recommended family based interventions that reduce parental stress during gestation, more research into rehabilitation in intensive care and in the early months of life, and greater understanding of the role of environment and parenting after birth.
“The more we understand about the factors that support or hinder brain development following very preterm birth, the greater the opportunity to find strategies to enhance their long-term wellbeing,” Anderson said.
Prof Jeanie Cheong, a neonatal paediatrician at the Royal Women’s hospital in Melbourne, said reviews of the field are regularly published in specialist journals, but inclusion in the NEJM, a renowned general medical journal, means the area is becoming a priority.
“It really highlights how far we’ve come in the field of preterm birth and outcomes,” she said.
Cheong said outcomes early in life can have lifelong implications.
“Babies don’t remain babies for ever. They grow up to be children, young adults and older adults,” Cheong said.
“It’s important for the general community, medical community and also the individuals themselves to appreciate that as we have more and more of these very vulnerable babies survive and grow up to older ages, it’s really our duty to make sure that appropriate resources go into the research, and also the clinical care to optimise their lives.”
