Extremely premature babies run a much higher risk of developing autism (ASD) in later childhood, according to a new study by researchers from Karolinska Institutet and Karolinska University Hospital in Sweden
The study published in the journal Cerebral Cortex suggests that babies born more than 13 weeks prematurely run a serious risk of brain damage, ASD, ADHD and learning difficulties.
The researchers examined over 100 babies who had been born extremely prematurely (i.e. before week 27, the beginning of the third trimester). They studied the growth of the babies’ brains using magnetic resonance imaging (MRI) during the neonate period, and then screened the children for autistic features when they had reached the age of six-and-a-half.
‘We were surprised by how many – almost 30 per cent – of the extremely preterm-born children had developed ASD symptoms,’
says Ulrika Ådén, researcher at the Department of Women’s and Children’s Health at Karolinska Institutet and neonatologist at the Neonatology clinic at Karolinska University Hospital in Sweden.
‘Amongst children born after full-term pregnancy, the corresponding figure is one per cent.’
The researchers found that it was more common in the group of children who had developed ASD for there to have been complications during the neonate period, such as surgery, than it was amongst their prematurely born peers who had not developed ASD.
Already in the neonatal period, long before the children had manifested signs of autism, differences could be observed between the extremely preterm babies who went on to develop ASD and those who did not, with diminished growth of the parts of the brain involved in social contact, empathy and language acquisition – functions that are impaired in autistic children.
The study supports previous findings indicating that environmental factors such as birth weight and complications can increase the risk of autism.
‘The brain grows best in the womb, and if the developmental environment changes too early to a life in the atmosphere, it can disrupt the organisation of cerebral networks,’
Dr Ådén said.
‘With new therapeutic regimes to stimulate the development of such babies and avoid stress, maybe we can reduce the risk of them developing ASD.’