Physical activity is a great way to stay healthy throughout pregnancy, to reduce stress, and to prepare yourself for childbirth. The most important message that I always tell women is to listen to your body.
So for example, if you like to go running, most women will either start to slow down the pace of their running – sometimes they'll shorten their mileage – or they'll do a combination of walking and running. I do tell women that it's fine to continue a regimen that they're already comfortable with, but talk to your doctor before you start a new regimen. Great exercises during pregnancy that you can do throughout the whole time include yoga, walking, and swimming. And make sure that you drink lots of water.
There are certain activities that we recommend that you absolutely avoid during pregnancy. These include contact sports and other sports that have a high risk of falling, which include skiing, horseback riding, and biking. And scuba diving we don't have very much information about, so we do not recommend scuba diving in pregnancy. Also, throughout your pregnancy, your center of balance starts to change, so please be cautious with that. And avoid lying flat on your back from about the midpoint of your pregnancy on.