For many longer surgeries, once you are sleeping your legs will be spread and they will insert a catheter. They will find out about your period then. For shorter surgeries that don’t need it inserted, they often ask.
You sure can – lots of women do. Often surgery is booked so far in advance its hard to know if you will be having your period. If its gynecological surgery – ask your doctor ahead if it’s a problem if you start your period. If it is, they will let you know where to call the day before.
Most surgery isn’t bothered at all by being on your period. And, if you’ve had surgery before you know the nurse tends to ask as they prep you if you are on your period.
If you are, they will make sure to deal with your pad and get you into a fresh one before you wakeup.
You generally aren’t allowed to wear a tampon during surgery. Switch to a pad before they take you in. If you do forget your tampon, it isn’t a big deal. They will check you once they know you are on your period. If they find a tampon, they will remove it and you’ll wakeup in a pad.
Does it feel weird to know they changed your pad or tampon while you slept? It sure does – but its just a normal part of being a girl and having surgery. Its only weird for you – not them.