My doc told me that if u have a normal pregnancy u can continue ur normal exercise routine
all the way through as long as ur tolerating it well. She had me eliminate fall risk at 12 weeks... for me this was snowboarding. But other than that I am 34 weeks and still exercising 5 days/week. I still run, do yoga, do insanity videos with some modifications, T 25 videos, elliptical, and hike on weekends (6-7 hilly miles at elevation), etc. I modify things on a daily basis.