i used to jog 3-4 times per week before being preg, and still do - but slower and more like 2-3 times per week...am also doing some swims and bike rides and i expect that as i get bigger i will mostly be swimming...last time i swam 1-2 km a couple of times a week throughout (was swimming two days before birth - and then had water birth!)..i really felt the exercise helped a lot with preg and labour and want to continue it this time as much as i can. besides i have to as i eat like a pig and need to work it off!