Posted by: Ticktock | July 27, 2010

Autism and Ultrasound?

Dr. Manuel Casanova, a scientist from the University of Louisville, is concerned about a possible link between ultrasound and autism. He doesn’t have any evidence for this hypothesis, but he felt the need to communicate his fears to the press. Why?

The reason Dr. Casanova is concerned about autism stems from his own personal bias. He readily admits that his grandson has severe autism, but he gives no reason for suspecting ultrasounds as the cause other than seeing an ultrasound photo at the front of his grandson’s first photo album.


Dr. Casanova, who in all other respects seems to be a reputable neurologist,  has clearly never heard that there’s a difference between correlation and causation. It’s fine to have a hypothesis and to test it, but going straight to the public based on your biased hunch is irresponsible.  Ultrasounds are often medically necessary, coloring them in such a bad hypothetical light will make pregnant mothers unreasonably paranoid.

I’m more than willing to admit that I’m out of my leagues challenging Dr. Casanova, but my comments are based on what he presented to WHAS News in Louisville, Kentucky. I do plan on following up on this in the near future.



  1. There’s a lot of speculation going on because people are worried – and rightfully so – that they could have a child with spectrum disorder. I wish we would stop talking about speculation and start talking about science. One thing we do know is there is a connection issue between the two sides of the brain and now we know the brain CAN be changed. Here is an article that will explain the science!

  2. They aren’t talking about the science as there isn’t any.

    I looked fairly closely at the research on ultrasound safety a while back as here you can get DVDs made of your baby with very fancy ultrasound equipment privately.

    I looked at the safety research expecting to find some risks, and ultrasound is pretty much as safe as medical procedures get.

    I can’t say I’d leap at getting a fancy video of a baby in the womb, much as I enjoyed the quick peak the routine checks provided, but I can’t see any evidence it shouldn’t be done by those with the money and inclination.

    He can’t note rising rates of autism coinciding with increased ultrasound, if the studies on autism rates are unclear that it is increasing at all. i.e. You can’t correlate rise in A with rise in B, if B didn’t rise.

    Meanwhile back in the real world we can’t prove the safety of ultrasound. All you can do is look at the extensive research that has failed to find any(!) adverse effects from medical ultrasounds in humans and base any decisions on that.

    No doubt a retrospective study or two will help establish if this is worth researching further, but on current EVIDENCE don’t worry about medical ultrasounds.

    I’m not a doctor, wait for Steven Novella to comment for the skeptical neurologists view.

  3. Ultra sound is also used to force weight loss because it heats up flesh. Google it. I’m not saying that it can in fact cause Autism in children, but it is not 100% safe either.

    • Ultrasound devices used in weight loss are designed to cause cavitation lysis.

      Cavitation in diagnostic ultrasounds is a rare event, and a lot of engineering has gone into trying to prevent it happening.

      Start here

      There is no evidence of harm yet from diagnostic ultrasound. So whilst it is not possible to say it is 100% safe, it has never been shown to be harmful. [Note this is extremely unusual, most things used in medicine have some harm demonstrable under some conditions]

      Worrying about something that has never been shown to be harmful, and which has been extensively studied for safety, is irrational.

      Sure I’m happy for people to research it further, there is always scope for something to have been overlooked. But folks seem desperate to turn this into some sort of scare on the basis of zero evidence.

      We live in a world with a whole lot of environmental changes that have taken place in the last few decades. People have suggested most of them might be linked to autism at some point from aluminum to mobile phone transmissions.

      Given the difficulty demonstrating a genuine rise in autism rates has taken place, it is unlikely any of them are substantial contributors to autism risk.

  4. I believe ultra sound could be a cause of autism since there has been such an increase in the last 36 years and now almost all mothers have one or more ultrasounds. Ultrasounds send sound waves through the amniotic fluid and the baby hears these high pitched sound waves. They should do a study to see by not giving mothers ultrasounds, if they are not necessary it certainly is not worth the risk. Didn’t they do a study once on how sonar disturbs the sealife?

  5. Hi,

    Sorry if I am intruding. It may help the discussion if I clarified a couple of things. The controversial TV interview focused on transcranial magnetic stimulation. I only discussed ultrasound tangentially but the reporter chose to air the same despite my warning that the same would be rather premature. Still, the reporter did not dwell on any of my reasoning to invoke ultrasound as a risk factor for autism. This is based on neuropathological studies where I have noticed similarities between animal models receiving ultrasound and postmortem studies from our group in series of patients with autism. This is not a hunch and I have made more studies in this area than probably anybody else within the literature. I recently published an article (quoted in the interview) primarily as a way of elucidating putative mechanisms that are involved in both conditions. My major recommendation within the article was for ultrasound to be used according to existing safety standards. I do appreciate the concerns that the interview may have created. Viewing the TV segment alone I would have had the same concerns. If anybody is interested in pursuing this dialogue or require further information (e.g., pdf’s of relevant publications) please email me directly at

    Thank you.


  6. Read this and tell me there is no scientific evidence for the U of L doctor’s response.

    • I read it. The scientific evidence seems to be missing a few key parts. I’d like to see the numbers on how much heat increase a fetus experiences and for how long. I didn’t see that, perhaps I simply missed it. I’d also like to see a study that demonstrates that there is a lower incidence of birth defects or autism in a population with low rates of ultrasound usage. Right now, it looks like this is not a well-supported hypothesis. That could of course change with more research, but right now I’m not seeing much in the way of actual evidence.

  7. it may not be caused by the heat. Ultrasound moves the cells and molecules of a developing brain. In artificial neural networks this causes the network to “forget” what it has learned. “Jiggling” the neurons causes the temporarily stabilized configurations to return to essentially random configurations.

    My wife is currently pregnant and she has no science training, and is moreover quite sensitive and inclined to trust doctors. For example, if the doctor says that they would like to do ultrasound to rule out a heart problem, she is unable (or too worried) to realize that in her (extremely low) risk group the probability of any useful information from the ultrasound is about .01% (that’s 1 hundredth of 1 percent). When I try to talk about it she gets very upset and that’s not good either. The doctors have not really helped much at all with their nebulous speculation about “possible problems”.

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