Pelvic ultrasound question

M

I am scheduled to have a pelvic ultrasound for infertility reasons the day that I am 13 dpo. I plan to do a frer that morning.

In the case that I am pregnant but the test doesn't pick it up that morning, is there any harm in having this ultrasound?

Sorry I don't know how it works or what all they would check as I've never had one. I just don't want to do anything that would cause any harm if I were the be pregnant.