Does Prenatal Ultrasound Cause Autism?

Caroline Rodgers, a science writer, has noticed some very interesting correlations:

The new autism figures published in the CDC’s 12-18-09 Morbidity and Mortality Weekly Report (MMWR) reveal an apparent anomaly: While there was an overall average autism increase of 57 percent in children born between 2002 and 2006, Hispanics in Alabama showed a 67 percent decrease in autism.

The mothers of the first batch of children who were eight years old in 2002 would have been pregnant in 1993. Therefore, I looked at what changes might have occurred in Alabama’s public health policy in 1993 that would explain a 67 percent drop in the autism rate of Hispanic children born between 2002 and 2006.

According to the 2002 PRAMS Surveillance Report: Multistate Exhibits Medicaid Coverage for Prenatal Care .

During 1993-2002, the prevalence of Medicaid coverage for prenatal care . . . decreased in 3 states (Alabama, Florida and West Virginia).

This particular correlation is in addition to a broad correlation between wealth and autism (more wealth, more autism):

Also significant in last week’s MMWR report were the ethnic differences in autism prevalence found among non-Hispanic whites, blacks and Hispanics. The autism rate in the monitored areas throughout the United States of children of non-Hispanic white women was 102 per 10,000; among black children, 76 per 10,000; and among Hispanic children, 61 per 10,000 – roughly half of the non-Hispanic white rate. These results seem counter-intuitive, since the non-Hispanic white population could be expected to have more access to prenatal care than the black or Hispanic populations. Yet if autism risk is increased by exposure to prenatal ultrasound, these figures make perfect sense.

This isn’t cherry-picking. Rodgers believed that we should take seriously the idea of a prenatal-ultrasound/autism link based on entirely different data.

14 Replies to “Does Prenatal Ultrasound Cause Autism?”

  1. > While there was an overall average autism increase of 57 percent in children born between 2002 and 2006

    i have trouble believing that ultrasound was used much more in 2006 compared to 2001. it’s not a new technology.

  2. It’s not about having trouble believing something. That’s the type of cynicism that’s blunted almost all intelligent discussion regarding autism, particularly its increased diagnosis, likely relating to its increased incidence.

  3. Ultrasound use has changed rapidly in every possible respect over the last 20-plus years, whether in terms of scans per pregnancy, the gestational window of exposure or the type of scan.
    A study from Canada showed a 55 percent increase in scans per pregnancy for the 10-year period ending in 2006, with the highest percentage of increase among low-risk pregnancies, which the study authors pointed out were not medically indicated.
    A fairly new type of scan that should be of particular concern is the nuchal translucency scan, which must be performed between gestational weeks 10 and 14. The test measures the amount of nuchal fluid at the base of the neck.
    According to an expert on fetal ultrasound safety, this test has been standard in Europe for the last three or four years and has been recommended for all pregnancies since early 2009. At an ultrasound convention last year, I was told that this test was popular among U.S. doctors because it had a high reimbursement rate from the insurance companies.
    Every ultrasound scan has many variables, such as the amount of acoustic output, the dwell-time, type of equipment, etc. When the FDA approved an eightfold increase in power in the early 1990s, it required that thermal indicators be on every machine.
    Unfortunately, surveys within the industry reveal that most operators cannot even find the thermal indicators on their own machines; among those who can, very few know how to read them.
    Doctors and ultrasound technicians told me they were not concerned about the thermal indicators, pointing out that the machines and settings are both FDA approved for obstetrical use; unfortunately, these specs and settings are not based on safety — a fact that was confirmed for me by an FDA network leader.

  4. Like all medical interventions, the possible benefits must be weighed against the possible risks. There appear to be many benefits from ultrasound, as I experienced when my terrible abdominal pains were diagnosed as gallstones.

    Her information is intriguing and certainly deserves more research.

  5. The Brain that Changes Itself (a very interesting book about neuroplasticity) suggests that autism might be caused in vulnerable babies/toddlers by too much exposure to white noise. The idea is that developing the ability to perceive information is a crucial part of early development, and the brain is disrupted if there’s too much input that doesn’t have information.

    I don’t know if ultrasound is white noise (probably not), but the connection to sound is interesting.

  6. I’ve seen this hypothesis before, and I’m not sure what to make of it. Plausible, but unproven? The main thing I took away from reading this and other articles on the subject is that statistically, there’s no improvement in pregnancy outcomes when ultrasound is used. So it’s an unnecessary procedure, where you’re spending money for no real benefit (and, possibly, harmful). That’s all I need to know about it. I can wait till my babies are born to see what they look like.

  7. It does not seem like it would be difficult to do a survey of parents of five year old children, looking for a correlation of autism related symptoms to recollections of ultrasounds. It wouldn’t be the last word, but it would be something a statistics class could do as a class project.

    It would be cool if someone put together a web site of useful studies suitable for class projects.

  8. I had many ultrasounds (I lose count) because I was expecting twins and had gestational diabetes.

    I wonder if the increase in ultrasounds correlates with increased multiple pregnancies (which receive more ultrasounds) due to increased use of fertility drugs and reproductive technologies (IVF), as well as more pregnancies in older women, which also have a higher rate of twins.

    During my pregnancy, I read about the risk of autism from ultraounds, and it sounds very plausible. I couldn’t do much about it, though – in my case the benefits of regular screenings seemed to outweigh the risks of the ultrasounds. I was concerned, though, when the technicians would try to “give me a picture” by holding the wand over the fetus extra long – it was hard to say no because they seemed to perceive no risk in using more ultrasound than was necessary. One gave me a 3-D image without asking me, which pissed me off. (Is 3-D ultrasound good for anything but an early “baby picture”? Why does it exist?)

    Fortunately, my daughters, now age 2, seem far from autistic. I was glad I was carrying girls (lower risk of autism in general), considering all the ultrasounds they got. One does seem to be left-handed, which isn’t in itself worrisome, but I wonder if it could have been caused by the ultrasound. I remember reading one study that, while finding no increase in autism in children who’d had multiple ultrasounds, found a higher rate of left-handedness among male children, indicating that the ultrasound did *something* to the brain.

  9. BTW, @ Caroline Rogers – We had the nuchal fold ultrasound test at 11 weeks because it was safer than amniocentesis or chorionic villus sampling and was available earlier in pregnancy. Although we would have continued the pregnancy whatever the finding, the results gave us peace of mind and we felt no need for further tests. I didn’t know at the time that there were particular concerns with this type of ultrasound, but I probably would have done it anyway.

  10. You would not believe how long ive been searching for something like this. Scrolled through 7 pages of Google results without finding anything. One search on Bing. There was this… Gotta start using this more often

  11. I have an ASD diagnosed seven year old daughter. I have been wondering since her regression at fifteen months and diagnosis shortly there after, if there was a link to her diagnosis and the many ultrasounds I had. I don’t understand why this possible link has not been researched more. I had a high risk pregnancy and got an ultrasound everytime I walked through the door, whether I liked it or not. I also had a chorionic villus sampling done at eleven weeks where the Doctor just seemed to rest the ultra sound device on my belly as my husband asked questions for the next thirty minutes, after the test. I hope that someone will finally run the numbers…so often ultrasounds are unnecessary. Wouldn’t it be tragic, if such a simple unnecessary procedure, ends up being a major contributing factor? Isn’t about time that someone reserched this seriously?

  12. I have been looking into this for a number of years. I contacted several Medical research groups & none were interested in looking into this. I also Contacted Dr. Woo, “the athority” on prenatel ultrasound. He has yet to respond.
    Autism is increasing in the more affulent areas where prenatal ultrasound are more likly to be used .
    As we know ultresound is microwaves, as in ovens. Microwaves were expermented with to put out forest fires, which they did very well but also cooked anything alive in the area.
    I think there is a diffenite connection between Autism & Ultrasound.

  13. A few years ago I saw a brief item in a medical newsletter about a study done with pregnant rats. Offspring of rats who had ultrasound showed alteration in development of the brain. I wish I could cite the reference, but it could have been “Mood, Mind and Memory” or something like that, or one of the newsletters from a medical school, or even a pathology newsletter. I know it was since 2005. I thought of autism at the time and hoped someone in an appropriate field would follow up on it.

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