Pretty sure as soon as you’ve got a surgery date you’ll lose out on at least some money, either your deposit or a fee to change the date. They’re quite strict with pregnancy and my PC kept mentioning it in my consultations..
If you’re planning/trying, why don’t you call your PC and see if you can cancel your surgery date and wait to have them done? I’ve been warned my boobs will change when I have kids but that’s a few years off for me so I didn’t want to wait until after I’ve had my family.
Good luck whatever you decide x