Any mom's who swim?

I recently started swimming to get back in shape a bit before baby comes (I'm just about to hit the third tri), and I think I might want to have swimming become my main source of exercise.

Any mom's who swim? Does it get harder after baby comes? How much can I do without harming my unborn child? My doctors office isn't open until tomorrow and my curiosity and excitement is killing me.

I just want to feel better and more confident and have a good time, any input would help!