Letters to the Editor  |   July 2009
Does Prenatal Ultrasound Increase Risk of Autism?
Author Affiliations
  • Jed G. Magen, DO
    Department of Psychiatry, College of Human Medicine, Michigan State University College of Osteopathic Med icine, East Lansing
    Associate Professor and Chair
Article Information
Imaging / Obstetrics and Gynecology / Pediatrics / Psychiatry
Letters to the Editor   |   July 2009
Does Prenatal Ultrasound Increase Risk of Autism?
The Journal of the American Osteopathic Association, July 2009, Vol. 109, 383-384. doi:
The Journal of the American Osteopathic Association, July 2009, Vol. 109, 383-384. doi:
To the Editor:  
In his February letter to the editor, Christopher D. Olson, DO,1 suggests that ultrasonographic examinations during pregnancy may be etiologically related to the development of autism. He cites a report by the Centers for Disease Control and Prevention (CDC)2 that seems to suggest a recent, large increase in the prevalence of autism spectrum disorders (ASD). If this large increase were true, Dr Olson's suggestion might make sense. However, despite the commonly held belief that many more children are currently being diagnosed with ASD than in the past, there is good evidence that the true incidence and prevalence of ASD may not have increased.3,4 
Clarifying this matter goes beyond splitting the proverbial hair. Understanding the true incidence and prevalence of any disorder is important because it helps healthcare providers determine those resources needed to devote to treatment. In addition, medical and public health professionals must educate the public about this matter so that parents have a realistic understanding of the health problems that can potentially affect their children. Poor or misleading information can be worse than no information at all. 
Dr Olson1 quite appropriately cites the controversy regarding autism and childhood vaccinations as an example of poor information leading to inappropriate withholding of vaccines. 
Similarly, the idea of an increase in ASD may well be another result of selective reading of the literature—which actually offers much less definitive conclusions than proponents of an increase generally acknowledge. 
Barbaresi et al3 examined diagnoses of ASD that were made in Olmsted County, Minn, from 1976 to 1997. They concluded that an observed increase in incidence and prevalence of clinically diagnosed ASD during this period may have been related to various confounding factors rather than a true increase. These factors included “diagnostic shifting” (ie, changes in the diagnostic criteria used in analyses), as well as increased availability of educational services to the public, resulting in increased public awareness of autism.3 
Furthermore, the same CDC report2 cited by Dr Olson1 notes that, of the six sites for which prevalence data were available in 2000 and 2002, autism rates were stable in four of the sites. Although rates in the other two sites increased between these 2 years, the increase was described as statistically significant at only one of these sites.2 
Latif and Williams4 found that, during a 16-year period (1988-2004), prevalence rates of ASD in several districts of South Wales, United Kingdom, rose based only on “increased referral rates and improved diagnosis of childhood autism at an earlier age.” 
Of course, proponents of an increase in the incidence of ASD can cite equally compelling data to support their contention. The main point to remember in this debate is that published literature on the epidemiologic factors of autism and related disorders is not definitive—for either an increased or unchanged incidence. 
Despite our preference for definitive answers to questions, readers of JAOA—The Journal of the American Osteopathic Association may want to refrain from jumping to premature conclusions regarding the epidemiologic factors—including a possible relation to ultrasonography—of autism and related disorders. 
Olson CD. Does prenatal ultrasound increase risk of autism [letter]? J Am Osteopath Assoc. 2009;109:71-72. Available at: Accessed July 6, 2009.
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: Accessed May 4, 2009.
Barbaresi WJ, Colligan RC, Weaver AL, Katusic SK. The incidence of clinically diagnosed versus research-identified autism in Olmsted County, Minnesota, 1976-1997: results from a retrospective, population-based study [published online ahead of print September 13, 2008]. J Autism Dev Disord. 2009;39:464-470.
Latif AH, Williams WR. Diagnostic trends in autistic spectrum disorders in the South Wales valleys. Autism. 2007;11:479-487. Available at: Accessed May 4, 2009.