until about 14 weeks it is perfectly safe to do any of your normal activities, it's even safe to ski (if that is one of your regular activities). Do whatever you like, just stay away from strenuous abdominal activities.
Try and find a waterfitness class (at the Y), it works wonders, and you CAN NOT do anything in the water (exercise wise) that is going to in any way, shape, or form harm the baby. You also build really lean sleek muscles from water exercise, not bunchy stock muscle mass like you do on land.
Walk, walk, walk. It is recommended that you walk between 2-3 MILES at least 3 days a week, and take at the very minimum a 30-45 minute walk daily. And get your heart rate up, break a sweat.
Also try pilates (several good classes for pregnant women)... any HYDRATE with h2o, no tea, juice, pop, "calorie free drinks", or flavored waters.
at 11:52 AM on Feb. 21, 2010