A new study showed infants who were born with low birth weight and prematurity have more than a double risk of developing autism, but more so for girls than for boys.

Researchers at the US Centers for Disease Control and Prevention compared the data from 565 children in Atlanta born between 1986 and 1993 with autism with the ones from a control group.

The results showed that a birth weight below 5.5 pounds is associated with an overall 2.3-fold increased risk for autism (boys with less than a twofold increased risk and girls a three times or higher risk).

Although the results showed no link to preterm birth earlier than 33 weeks and autism for boys, there is a significant fivefold increased risk seen for girls with autism.

They also found that low birth weight and early preterm birth affected groups of children differently, depending on whether they had autism alone or autism and other developmental disabilities.

"What is new in this study is the in-depth look at the gender effect," Diana Schendel, lead health scientist at the National Center on Birth Defects and Developmental Disabilities at the CDC in Atlanta said.

The findings support the idea that there are different kinds of autism and different mechanisms underlying those cases.

The results do reinforce the importance of monitoring children who are born underweight or early for behavioral problems so they can be treated, said study author Schendel.

While there's no "cure" to avoid low birth weight, Schendel advised pregnant women to seek prenatal care as early as possible.

She said it's important, for instance, for pregnant women not to smoke cigarettes and to avoid infections, among other healthy lifestyle habits.

(Agencies via Xinhua News Agency June 3, 2008)