Children with autism who are born a few weeks early or late tends may suffer more severe symptoms and engage in more self-injuring behaviors than those born on time, according to new research out of Michigan State University.
The study, published online in the Journal of Autism and Development Disorders, found the increase in more severe symptoms may be attributed to some of the underlying causes of why a child is born preterm (prior to 37 weeks) or post-term (after 42 weeks).
Previous research has linked premature birth to higher rates of autism, but the new study is one of the first to compare the severity of the disease among children born early, on time and late.
"We think about autism being caused by a combination of genetic and environmental factors," said lead researcher Tammy Movsas of MSU's Department of Epidemiology. "With preterm and post-term babies, there is something underlying that is altering the genetic expression of autism.”
For the study, Movsas and colleagues analyzed a database compiled by Johns Hopkins University of 4,200 mothers – with autistic children ages 4-21 – between 2006 and 2010. It divided the births into four categories: very preterm (prior to 34 weeks); preterm (34 to 37 weeks); standard (37 to 42 weeks); and post-term (after 42 weeks).
The mothers were also surveyed about the symptoms of their children, and the results revealed very preterm, preterm and post-term autistic children had significantly higher screening scores for autism spectrum disorder than those born full term.