Low birth weight increases autism risk

SALT LAKE CITY — Babies born too soon and too small have a higher risk of developing autism, according to a study published Monday in Pediatrics.

Researchers at the University of Pennsylvania School of Nursing and School of Medicine and the Children's Hospital of Philadelphia followed more than 1,100 preemies born in New Jersey between Oct. 1, 1984 and July 3, 1989 weighing less that 4 pounds 7 ounces at birth. They found 5 percent met the criteria for an autism spectrum disorder by age 21 — about five times higher than that of the general children's population. The Centers for Disease Control and Prevention set that number at 1 percent for all children at age 8.

The new study emphasizes the importance of early screening of all children, said Jennifer Pinto-Martin, lead researcher and director of the school's Center for Autism and Developmental Disabilities.

A story on CNN's website about the study noted that about 3 percent of American newborns fall into the low-birth-weight category used by researchers. "Babies of this size are typically born prematurely, though certain pregnancy complications can also cause low birth weight in full-term babies," it said. It's not the first study to suggest that underweight babies have a higher risk of autism. But those studies and the new one doesn't say if the low birth weight "directly contributes to ASDs," CNN said.

"For years we have known there's a higher risk of delay and some impairments in some domains of development in low birth-weight babies," Dr. Diego Chaves-Gnecco, a pediatrician at the Children's Hospital of Pittsburgh, told CNN. He was not involved in the study.

Low birth weight also comes with well-documented increased risk of cognitive and motor disabilities. Pinto-Martin said that all children should be screened early, but it's especially important for those who are premature and very small. She told Health.com that "development screening is often something that is pushed to the side. It's important we do a really good job of screening every single child." And she noted that the earlier a child is screened, the better off that child might be over time. "Early intervention improves long-term outcome and can help these children both at school and at home," she said in a written statement.

The release noted that in future studies, Penn researchers will look at brain ultrasounds taken of the newborns to see if there are links between brain hemmorhage, which is a common complication of being born too early, and autism.

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