Running: we recommend only running until you are 25 weeks
Rock climbing (not bouldering): you must wear a pregnancy specific harness called the Mountain Mama see link for ordering: http://www.mountain-mama.com/products/the-mountain-mama-by-mad-rock#.Vh2CvstX5_w
Swimming: this is a good option during your entire pregnancy. Even if you just float or do water walking, it will help with swelling.
Yoga: select a prenatal yoga class if you are less experienced, but more experienced yogi’s can stay in regular classes since they are aware of body position practices.
Spin class: only if you have been biking prior to pregnancy . For some women who have anterior pelvic pain, this is not a good choice for them.
Pilates: Try the Reformer Classes instead of the mat or floor classes
Hiking: Set your own pace and make sure your breathing rhythm is even and not breathless (remember you are breathing for you and baby).
Body Sculpting classes: these classes prepare your body for labor and all the endurance of that event and pushing, but it may not be advised to start too late in pregnancy as you may have to much relaxation in your body.
With Zara, I ran 5 miles till I was 25 weeks along, then swiftly walked and also did yoga and power sculpting. With my current baby, I am running 2-3 miles, 3 times a week and I do rock climbing and at home squats, step-ups and calf raises and lunges.