GENDER & AUTISM: A U.S. government study suggests that premature or underweight babies—especially girls—are more likely to develop autism.

Research from a new study by the Centers for Disease Control and Prevention (CDC) shows that babies born with a low birth weight or before term have a two-fold risk of developing autism. To the researchers' surprise, girls are at a noticeably higher risk than boys.

Preemie and Underweight Baby Girls More at Risk

The CDC study compared 565 autistic children, born between 1981 and 1993 in the metro Atlanta area, to a control group of children with no developmental disorders. For their comparison, researchers defined:

• low birth weight as less than 5.5 lbs
• premature as gestation periods less than 33 weeks

CDC researchers found the following:

• Babies born weighing less than 5.5 lbs and delivered before 33 weeks' gestation had double the autism risk as babies born heavier and later.
• Girls born underweight and/or prematurely had a greater likelihood to develop autism than boys born under the same circumstances.
• Girls born prematurely had more than five times the risk for developing autism than girls born later.
  

• Boys born underweight and/or prematurely had no significant increased likelihood to develop autism, or less than two times the risk.
• Girls born underweight were three times more likely to develop autism than girls born weighing more than 5.5 lbs.

Researchers also grouped babies born with autism and at least one other developmental disorder, such as mental retardation, cerebral palsy or vision impairment, into subgroups. They observed greater differences in autism subgroups. For instance:

• Girls born with a low birth weight were four times more likely than girls in the control group to develop autism if they also had mental retardation.
  
• Boys born underweight showed no significant increase for developing autism when they also had another developmental disability.

One in eight births in the United States is premature.

Surprise Gender-Autism Link

The findings surprised researchers because autism is considered more of a male phenomenon (see sidebar). And while scientists have believed autism has both genetic and environmental components, this study suggests gender should be looked at more closely.

"What is new in this study is the in-depth look at the gender effect," said Diana Schendel, one of the study's authors and lead health scientist at the National Center on Birth Defects and Developmental Disabilities at the CDC. (Xinhua, 6/2/08)

Still, some medical professionals are quick to point out that the study's findings have not uncovered any cures or new treatments for autism.

"This gives us more clues [about autism], which we desperately need, but it's not anything clinicians can use right away," said Dr. Cindy Molloy, an autism researcher and clinical assistant professor of pediatrics at the Center for Epidemiology and Biostatistics at Cincinnati Children's Hospital. (U.S. News and World Report, 6/3/08)

Early Detection and Healthy Pregnancy Vital

While there is no cure for autism, medical researchers agree that babies born underweight or prematurely should be regularly checked for autism and other developmental disorders. Early detection can lead to more effective treatments and have a greater impact on behavior.

According to medical professionals, the study's findings also reinforce the importance of a healthy pregnancy. Expecting mothers should maintain a healthy diet, exercise and reduce their stress levels, doctors say.

Copyright © 2010 Informify

Question for Readers:

What factors do you think might contribute to premature or underweight infant girls being more likely to develop autism than boys?