The following is a summary of the American College of Obstetricians and Gynecologists' guidelines for exercising while pregnant (from Obstetrics & Gynecology 2002; 99: 171-173).
1. In the absence of contraindications, pregnant women are encouraged to engage in 30 minutes or more of moderate exercise on most, if not all, days of the week. As always, check with your doctor before beginning any exercise program.
2. During the second and third trimesters, pregnant women should avoid standing motionless for too long and exercising while lying on their backs.
3. Participation in a wide range of recreational activities appears to be safe. However, activities with a high risk of falling or abdominal trauma should be avoided; these include basketball, soccer, in-line skating, downhill skiing, horseback riding, ice hockey, gymnastics and vigorous racquet sports.
4. Scuba diving is not safe at any time during pregnancy.
5. Exertion at altitudes of up to 6,000 feet appears to be safe. However, engaging in physical activities at higher altitudes carries various risks and should be avoided.
Diastasis, a condition that sometimes occurs during pregnancy, is a separation of the rectus abdominis muscle. You can check for it before or after you give birth by lying on your back with your legs bent, feet flat on the floor. Place your fingers horizontally 1 to 2 inches above or below your bellybutton. Lift just your head off the floor and feel for a separation the width of three fingers or more. If you have a diastasis, don't be alarmed, but do avoid pressing your belly outward or rotating your torso when doing abdominal exercises--you'll exacerbate the separation.