Pregnancy Weight Gain Linked to Autism Spectrum Disorders in New Study

Pregnancy weight gain and the chances of a woman having a child with an autism spectrum disorder may be linked, a new study published in the journal Pediatrics found. 

In the past, studies have found links between a woman's pre-pregnancy body mass index (BMI) and pregnancy weight gain and an increased risk for the development of ASD in children. In the new study, researchers from the University of Utah built on this by identifying an association between ASD risk and prenatal weight gain after accounting for related factors, including BMI.

"The risk of autism spectrum disorder associated with a modest yet consistent increase in pregnancy weight gain suggests that pregnancy weight gain may serve as an important marker for autism's underlying gestational etiology," said Dr. Deborah A. Bilder, lead author of the study and an assistant professor of psychiatry.

"These findings suggest that weight gain during pregnancy is not the cause of ASD but rather may reflect an underlying process that it shares with autism spectrum disorders, such as abnormal hormone levels or inflammation."

The researchers compared a group 128 children diagnosed with ASD to a control group of nearly 11,000 children of the same age and gender. They then looked at a second group of 288 children diagnosed with ASD and compared their data with unaffected siblings. In both instances, pregnancy weight gain patterns were a common factor in children being born with ASD.

"The findings in this study are important because they provide clues to what may increase the risk of having an autism spectrum disorder and provide a specific direction for researchers to pursue as they search for the causes for autism spectrum disorders," Bilder said. "Doctors have known for a long time that proper nutrition is essential to a healthy pregnancy. Pregnant women should not change their diet based on these results. Rather, this study provides one more piece for the autism puzzle that researchers are exploring."