Does it get stretched out, and does it leave scares?
Thats what my friends told me, but I want to get mine pierced.
Not if you take care of it. Daily lotion will prevent scars but you have to be careful not to let your body push it out. Since your stomach swells up and your belly button pushes out when your pregnant, the ring might naturally push through it's hole. You can't feel it but it is really weird! If you take out the ring once you start getting big (I.e. 6/7 months along) you can always put it back in without having to repierce. It'll just fill up with scar tissue which breaks apart fairly easily. Or take it out when you get big but poke through the hole every day or 2 and it won't close or fill up with tissue AND it won't stretch or get pushed out!
I don't think it's recommended... I would just wait until either before or after you are pregnant.
Your belly button inverts when you are pregnant so you have to take it out. I have seen pregnancy navel rings which are really long and plastic but they won't accomodate full pregnancy size. It leaves a scar. My sister in law had this experience.