belly button piercing !

Hey everyone! So I'm 19wks & 5 days! Woo almost half way! & I have my belly button pierced I still have a normal metal stud in, but I got some plastic ones for pregnancy I was wondering when I should switch them? Is sooner better then later? I just don't want to cause problems with it so get nervous with changing it my bump is barely there so I'm scared I'll get it caught on things?