Haha thanks everyone!!! I didn't mean to hijack this thread!!
Regarding maternity suits, I think (but don't know for sure!) that they are just way more stretchy or have more material so you can fill them out as you get bigger. They pretty much just come in S,M,L,XL or whatever like regular clothes! I haven't ventured into maternity wear yet but you are supposed to just buy your regular non-pregnant size, and they are supposed to fit you as you keep growing. Oh and I've only seen the bathing suits that are tankinis that make it look like a one-piece because the top comes down over the bottoms.