Current controversies: exercising during pregnancy.

The current emphasis on physical fitness has motivated many women to participate in a variety of exercise programs. Increased participation by pregnant women is also occurring in the form of self-directed activities and/or as recommended by physicians in an effort to shorten labor and improve pregnancy outcome. Whether exercise improves or presents a potential hazard to the mother and fetus is a concern. The implications for the "trained" woman as well as the "untrained" exerciser are unclear and need definitive study.