A recently published study conducted by researchers in Seattle suggests that an ultrasound may contribute to autism severity.

University of Washington and Seattle Children’s Research Institute explored a hypothesis into the possible relationship between the severity of autism spectrum disorder and ultrasound exposure during the first trimester of pregnancy in fetuses with a genetic predisposition to autism spectrum disorder.

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"While subject to routine clinical practice and generally considered safe, there exists speculation, though no human data, that diagnostic ultrasound may also contribute to ASD severity, supported by experimental evidence that exposure to ultrasound early in gestation could perturb brain development and alter behavior," the study abstract states.

"We found that male children with ASD, copy number variations (CNVs), and exposure to first trimester ultrasound had significantly decreased non-verbal IQ and increased repetitive behaviors relative to male children with ASD, with CNVs, and no ultrasound," the study said.

The data suggest that changes in ASD symptoms may result from exposure to diagnostic ultrasound during early prenatal development of children with specific genetic vulnerabilities.

The study, published in medical journal Autism Research, says it used no human data. Researchers used retrospective analysis of data from Simon's Simplex Collection autism genetic repository, which contains samples from families with a child affected by ASD.

"There has been a real struggle in figuring out why there are so many kids with autism," lead author Sara Webb, UW professor of psychiatry and behavioral sciences, said in a news release. "Where does this disorder develop from and how do kids get autism? And a second question is, why are kids with autism so different from each other?"

As a mother of two, Webb said given what she knows now, she would not have an ultrasound in the first trimester unless there is a medical necessity.
 
The study's results relate to the first trimester of pregnancy; data from looking at the effect of ultrasound on the second and third trimester showed no link.
 
FDA guidelines recommend that diagnostic ultrasound be used only for medical necessity.
 
Corresponding author, Pierre D. Mourad, a UW professor of neurological surgery, believes the implications of the results are to bolster the FDA guidelines.