I took mine out with DD1 and got it pierced again but with DD2/3/4 i took it out and just thread it through every few weeks so the hole was still there. You can get flexible plastic bars for pregnancy too so call around at some piercing shops just get the piercer to help you do it up as i know a few people that had problems getting them done up.

I have mine out and it looks strange!!!! but my belly is too yuck to show off anyway.