A review of literature dealing with exercise during pregnancy was recently published in Clinics in Sports Medicine . The author examined various types of exercise, levels of intensity, and health benefits to the mother and the child. Anecdotal evidence suggests that even weight training or scuba diving to less than 30 ft. may be safe during pregnancy, but controlled studies have not been done. Exercise at high altitudes should be done with caution since information is limited as to the safety. However, there have been no reports of injury, pregnancy complications, or losses associated with low-intensity exercise such as skiing, running, hiking, or mountain biking at moderate altitude.
Less information is available about the safety of exercise around the time of conception.
Exercise at various levels of intensity help to improve the mother's feeling of well being and level of fitness. Exercise also improves cardiovascular function as seen in increased cardiac output that continues into the postpartum period. Exercise also affects maternal weight gain and postpartum weight loss. Those who exercise during pregnancy and continue afterwards are more successful at returning to their pre-pregnancy weight and fitness level. There also seems to be a relationship between exercise and easier, less complicated labor.