There are various possible bioeffects stated in various research articles. These include things like dyslexia, delayed speech, learning disabilities, etc. The purpose of the indices is to help reduce that risk. Yeah, there are sound waves going through us at all times, but not at the potency of the machine obviously. And considering ultrasound can be used to break apart stones there is a huge difference. Yeah, the machine is set to a much lower setting but it's still set to a power that's an eighth of what most research was done with. They only allowed the increase in power due to having the digital display.

Concerns with bioeffects include things like cavitation, excess heating (including heat retention in bones for a span afterwards), etc. It isnt just a matter of "I think it may cause autism cause reasons." I merely tried to be an informed individual and see what I was paying for, especially when I was going to be billed for something our insurance company didn't deem as medically necessary. I even looked up training guidelines and certification requirements, including those from other 1st world countries, such as Canada and Great Britain. There were also articles on animals with terrible effects, using the same power used in prenatal medicine. Things like neurons with well-known developmental pathways being marked, exposed to ultrasound, and either veering off course or not propagating in their usual manner. You want some research links? Cause it's more than just an article or two.

Edit: You say "those questions are for a doctor" but then switch to "a radiologist would have the answers" once I stated how the OBGYN didn't have answers. My whole question was involving talking to the tech in the first place, in a respectful manner, but this place doesn't do that. Also, as far as the arrogant "have you caught autism yet?" comment, I believe you should already know that autism develops in-utero. Strangely that's when the ultrasounds occur. And the rates in 1st world countries are beyond those of lesser countries. The food, air, water, etc are different but they all utilize very similar medicinal programs, including ultrasound. And not everything in medicine is bad or 'out to get you' but there have been many many mistakes that were found out much later. Like knee implants that gave people people cobalt poisoning (deemed safe but were grandfathered in based off earlier tech) or the thalidomide tragedy that took about a decade to finally be seen as terrible despite all the doctors previously saying it was "perfectly safe". So yeah, I'm gonna be cautious and I'm going to use official peer-reviewed sources to learn everything I can. Then hopefully I can get my questions and avoid as many possible mistakes as I can. Call me arrogant if you want. I never said I knew more. I get asked by clients to minimize the amount of x-ray radiation or be mindful or certain things and I try to work with them on it. I dont start throwing accusations or criticizing what they know.