Researchers at Penn have come one step closer to understanding autism.
Babies with low birth weights are five times more likely to develop autism, according to a study released Oct. 17 by a group of researchers from the School of Nursing and the Children’s Hospital of Philadelphia.
The group, led by Penn professor and Director of the Center for Autism and Developmental Disabilities Research and Epidemiology Jennifer Pinto-Martin, began the research in the 1980s. The group studied infants born prematurely between October 1984 and July 1987 in New Jersey. All infants weighed no more than 4.4 pounds.
Over the course of 21 years, researchers screened them for symptoms of autism and performed further diagnostic evaluations to determine actual cases of autism within the group.
These diagnostic evaluations marked the study separate from other autism-related research, since most other studies focus only on screened cases of autism rather than an actual diagnosis. A screening of autism is more likely to yield a positive diagnosis of autism, given that many premature infants exhibit symptoms of autism that may diminish with age. Diagnoses yield fewer positive results and are therefore more accurate, Pinto-Martin said.
In the study, researchers found that 18 percent of their test group screened positive for autism. They also discovered the rate of an autism diagnosis within their test group was five times greater than the rate of autism in the general population — a comparison of 1 and 5 percent, respectively. These findings point to a more definite link between low birth weight and autism.
“This speaks to the need for very careful follow-up of children who continue to be born [prematurely] in increasing numbers,” Pinto-Martin said, adding that the increasing numbers of prematurely born infants is on the rise because of more advanced medical technology that has increased the survival rate among these infants.
While these findings are substantial, the team from CHOP plans to continue research on the correlation of various factors with autism. With 862 documented premature births in the study, these factors range anywhere from infections during the pregnancy to neonatal brain hemorrhages after birth.
Future research will focus mostly on neonatal brain hemorrhages, which often develop as a result of a premature birth when the infant’s brain is not fully developed and experiences easy bleeding or bruising.
While some brain hemorrhaging is of no big consequence and can be reabsorbed into the tissue, other instances leave more extensive damage and can interrupt neural connections — another likely factor in the risk for autism.
“The take home message here is that people who have children at a low birth weight should advocate for their child’s development. If they think something is wrong, they should seek help,” Pinto-Martin said, adding that treating the illness early helps the affected child to do much better throughout his or her life.
