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Letters to the Editor  |   February 2009
Does Prenatal Ultrasound Increase Risk of Autism?
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Article Information
Imaging / Obstetrics and Gynecology / Pediatrics / Psychiatry
Letters to the Editor   |   February 2009
Does Prenatal Ultrasound Increase Risk of Autism?
The Journal of the American Osteopathic Association, February 2009, Vol. 109, 71-72. doi:10.7556/jaoa.2009.109.2.71
The Journal of the American Osteopathic Association, February 2009, Vol. 109, 71-72. doi:10.7556/jaoa.2009.109.2.71
To the Editor:  
Autism spectrum disorders have become more common every year for the past several decades.1,2 The Autism Society of America2 states the following: 

In February 2007, the Centers for Disease Control and Prevention issued their ADDM [Autism and Developmental Disabilities Monitoring] autism prevalence report. The report, which looked at a sample of 8 year olds in 2000 and 2002, concluded that the prevalence of autism had risen to 1 in every 150 American children, and almost 1 in 94 boys.

 
Many lay people still believe that vaccines—especially the measles, mumps, and rubella vaccine and vaccines with mercury-containing preservatives—have contributed to the increased rate of autism, despite the lack of scientific evidence to support such a notion. 
We owe it to our patients to show them that medical research is actively searching for factors that may truly be contributing to the increased rate of this devastating disease. 
As the National Institute of Neurological Disorders and Stroke3 reports: 

Scientists aren't certain what causes autism, but it's likely that both genetics and environment play a role.... Studies of people with autism have found irregularities in several regions of the brain.... These abnormalities suggest that autism could result from the disruption of normal brain development early in fetal development caused by defects in genes that control brain growth and that regulate how neurons communicate with each other.

 
It occurred to me—as an osteopathic family physician who practiced obstetrics for many years—that during my more than 30-year career, the use of prenatal ultrasonography has also ballooned. 
When I was an intern, ultrasonography was being promoted to evaluate fetal maturity when mothers had unclear delivery dates. Ultrasonography was also used to assess unexpected fundal height growth, possibility of multiple births, and high-risk pregnancies. Today, it is typical for women with normal pregnancies to have multiple ultrasonographic examinations. 
Early in my career, osteopathic physicians were warned of the potential health risk of the heat generated by ultrasonography. In fact, today, ultrasound is used as a treatment modality in physical therapy, delivering deep heat to muscles and other solid tissue. 
Perhaps we have not considered fully the fact that liquid—such as amniotic fluid—absorbs more heat energy than does solid tissue. 
The developing fetal brain is known to be sensitive to a number of “environmental stressors,” including alcohol and various drugs. Is it possible that the amount of heat generated by multiple ultrasonographic examinations somehow lowers the threshold in fetuses that are at increased genetic risk of autism and related neurologic disease? 
I am not in a position to conduct research into such a possible connection, and I am also well aware of potential roadblocks to conducting such research—not the least of which is a fear-based reluctance among clinicians in a litigious society to give up the “safety” of the current standard of care. 
Nevertheless, in light of the huge social and financial impact that autism has on individuals, families, and communities, a research project investigating this possible correlation has the potential to be a hugely valuable endeavor. 
I envision the following kinds of studies: 
  • a retrospective study investigating the incidence of autism versus the use of ultrasound examinations in pregnancies
  • a study comparing the incidence of autism in populations that use little technology (eg, at-home births, people in underdeveloped countries) versus a university patient population that uses ultrasound examinations at the standard (ie, typically high) rate
  • a prospective multiyear study evaluating two patient populations, one with unlimited use of ultrasound examination and the other with this technology limited to high-risk pregnancies
I would like to challenge the osteopathic medical research community—particularly DOs in obstetrics—to take on this research project for the benefit of our patients. 
This pursuit has numerous potential clinical implications for the osteopathic medical profession's public health efforts. 
If any readers see the value in this course of action, I invite you to contact me. I would like to be involved in the project in any way that I can. 
Autism and Developmental Disabilities Monitoring Network Surveillance Year 2002 Principal Investigators; Centers for Disease Control and Prevention. Prevalence of autism spectrum disorders—autism and developmental disabilities monitoring network, 14 sites, United States, 2002. MMWR Surveill Summ. 2007;56:12-28. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5601a2.htm. Accessed January 29, 2009.
About autism page. Autism Society of America Web site. Available at: http://www.autism-society.org/site/PageServer?pagename=about_home. Accessed January 29, 2009.
National Institute of Neurological Disorders and Stroke. Autism Fact Sheet. Bethesda, Md: National Institutes of Health; April 2006. NIH publication 06-1877. Available at: http://www.ninds.nih.gov/disorders/autism/detail_autism.htm. Accessed January 13, 2009.♦