I had the pleasure to exchange discussion with Dr. Toms recently. To business, I do find his webpage self evident. Have a look yourself.
In his website he gives a thorough and well rounded description of ultrasound, but also discusses shortcomings in the research. He does not believe that ultrasound is very harmful, but earnestly raises concern that safety is not science fact.
I personally believe that ultrasound is a very promising tool that has great potential for good. Conservative use of it is the safest way to handle it until at least epidemiology can be performed. Until then, it is really a coin flip as to how ultrasound affects human development.
There are plenty of studies that suggest ultrasound of levels well below the intensity allowed in fetal scanning have potentially harmful bioeffects. Especially those that have been seen to directly alter the development of plants and bacteria …
True, it might not be autism or other mental illnesses known right now. Maybe ultrasound makes people smarter. I don’t know.
But it does something, and it’s definitely worth investigating further. Cures for diseases could be found, new applications, …ultrasound will harken a new era of medicine, I believe. I’ve read plenty of good things about ultrasound, too.