Children who born prematurely, before three months or more, are more likely to develop autism, a new U.S. study reported.

With the measurement of standard screening tool researchers found that, such kids are two to three times more prone to exhibit autism signs than the normal kids at the age of two years.

Autism also referred as autism spectrum disorders (ASD); that is a group of developmental disorders, illustrated as impaired social interaction and communication, and by constrained and repetitive behavior. ASD have strong genetic basis but the exact cause is still unknown.

Dr. Karl Kuban said, the elevated risk of autism indicated in these children may not be directly associated with premature birth. In spite of it, cause of autism, whatever it is, may force pre-term birth.

The researchers analyzed the 988 American prematurely born kids, at least 90 days before their expected birth date.

Then they were checked for the 23 behaviors to confirm the signs of autism through screening method, at the age of two. Results express that most of the children may have autism but this tool is not able to precisely diagnose the condition. Normally signs and symptoms of autism don’t appear before the age three, lead researcher said.

Since developmental problems in premature babies are common unrelated to ASD that could be the reason of positive result. Researchers then dropped children with vision, motor and hearing dysfunction. Even then, sixteen percent kids show positive results for autism.