A Melbourne study three decades in the making is challenging the idea that babies born extremely premature are at a higher risk of having ADHD or mood issues as adults.
The new research, which tracked a group of extremely premature babies born in Victoria in the early 1990s into adulthood, has found the rate of adult mental health issues in pre-term babies is comparable to those born full term.
"We really consider this a very positive and encouraging set of findings," Alice Burnett, researcher at the Royal Women's Hospital and lead author, said.
She said it was documented that babies born extremely pre-term were more likely to have ADHD — attention deficit hyperactivity disorder — but their research found that difference had diminished by the time they turned 25.
"At 25 years of age, extremely pre-term born young people and full term young people had similar rates of ADHD, anxiety, depression, and substance use problems," Dr Burnett said.
In 1991 and 1992, the researchers recruited a cohort of around 300 babies who were born extremely pre-term, meaning less than 28 weeks or at a birth weight of less than 1000 grams.
A collaborative research group followed their health outcomes against a control group of 300 babies who were born full term at the same time.
Monash University professor and ADHD expert Mark Bellgrove, who was not involved in the study, said the research was careful, controlled and showed promising results.
"It really suggests that the long-term outcomes for these kids or babies who are born pre-term are better than what was once thought," he said.
"It's a good news story for ADHD and broadly for mental health outcomes."
The researchers said there was a documented link between extremely pre-term birth and ADHD and anxiety in childhood, so it was still important parents of premature babies accessed support early in life.
The study showed a generally high prevalence of mental health issues among the young adult cohort whether they were born pre-term or not.
Between the ages of 18 and 25, for both groups the rate of ADHD decreased while anxiety and depression increased.
"We know that these are really common experiences for young people," Dr Burnett said.
"This study really emphasises how important it is that supports are available if young people need it."
Babies from the study now grown up
Holly Mason, who is now 30 years old, has been involved in the study for her entire life.
She was born weighing just 881g in March 1992 and was so small she could fit in the palm of her mother's hand.
Her mum, Jodie Prideaux, said she was only 25 weeks' pregnant when she went into labour.
"They said there was no stopping the labour," she said.
"It was very scary, it was very daunting — it felt like it was going on forever."
Holly participated in studies assessing her mental and physical health with researchers from the Royal Women's Hospital.
"I was more than happy to be part of it, because I'd been a part of it for most of my life," she said.
Advances in neonatal care lead to improved adult mental health outcomes
In the 1990s, survival rates for babies born extremely early more than doubled.
"There were some major medical advances in the early 1990s to support lung development, and babies' general physical health in the neonatal intensive care unit that really changed the rate of survival," Dr Burnett said.
In previous decades the survival rate of extremely pre-term babies was one in 10, but by the 90s that had increased to around 56 per cent.
Dr Burnett said she hoped the results of this study would be comforting to parents of premature babies born today and in the last few decades.
"It's a really exciting opportunity to be able to share some reassurance with families," she said.
"There are certainly lots of challenges still, in terms of other areas of development for babies born extremely pre-term.
"As survival rates continue to improve, we've got more and more of these babies, children, young people who were born very early.
"It's really important that we understand what the outcomes are for them."
