Can a trans-vaginal (internal) scan harm baby when listening to heartbeat?

[RainbowHope4]

I'm posting because I'm so worried. (Also posted in 'Pregnancy').

I'm pregnant for the 4th time (I've had 3 previous MC's).
I'm 7 weeks pregnant. We went for our first scan at our IVF clinic the other day.
I had an internal scan and she put the sound on and we heard the heartbeat.
She put it on for a long time (well about 30 seconds).
I panicked when she did this because I thought it was too dangerous to do this before 12 weeks due to there being too many sound waves being passed through to the baby which is too much for their little heart.
This is what I've read previously. And at our last clinic they told us they wouldn't let us listen to the babies heart because it was too dangerous at that stage, and it should only be done at 12 weeks onwards.
So now I'm panicking that harm could have been done.

I think you need to pose these questions to the clinic.

There are no risks associated with transvaginal ultrasounds. I'm not entirely sure how sound waves could be too much for a heart.

There's a debunked myth about a comparison to a subway train.

Hard to comment on what the last clinic told you.

As well as calling the clinic, my other recommendation would be to be careful with Google. Avoid over-googling and make sure you're reading reliable sources.

I was thinking of calling the clinic to ask them but I doubt they'd say they think it's dangerous if it's something they've done. I just remember my last clinic saying they'd never do it. Something about the soundwaves being too much, it generates heat or something and can be stressful to the baby's heart.