Its best to keep ur regular routine if you haven't had any complications you can double check with ur dr but snookie was doing it her whole pregnancy so I don't see why you wouldn't as long as ur having a normal pregnancy
I'm 35 weeks and I use the stationary cycles at the gym. I also walk, do light arm, chest and back workouts with weights (no more than 25 pounds), and though I haven't done it I've heard swimming is great. You'll know if you're over doing it.
I've been very active all pregnancy I still jog with my husky and I am 36 weeks, swimming is the best exercise and walking is also very good