Autism study bolsters link with preterm birth

WASHINGTON - A US study looking at children born more than three months premature provides new evidence linking preterm birth and autism.

These children were two to three times as likely to show signs of autism at age 2, as measured by a standard screening tool, compared with other children, the researchers wrote in the Journal of Pediatrics.

Autism refers to a group of developmental problems known as autism spectrum disorders that appear in early childhood and harm one's ability to communicate and interact with others.

Its causes remain unclear, and scientists have pointed to possible genetic and environmental factors.

Dr. Karl Kuban of Boston University School of Medicine and Boston Medical Center, who led the study, said the increased risk for autism indicated in these children may not be directly caused by being born prematurely.

Instead, it is possible that whatever causes a child to have autism also may force an early birth, Kuban said in a telephone interview.

With earlier research suggesting a link to preterm birth, the researchers followed 988 US children born very prematurely, at least three months before their due date.

At age 2, the children were evaluated using a screening method that applies a checklist of 23 behaviors for signs of autism. This tool flags children who may have autism but is not considered a definitive diagnosis.

Typically, a formal diagnosis of autism does not occur until around age 3, Kuban said.

While under 6 percent of children born full-term screen positive for possible autism using this tool, 21 percent of the prematurely born children scored positive, the researchers said.

Preterm birth is associated with a long list of health risks such as mental retardation, cerebral palsy, lung problems, and vision and hearing loss.