The U. S. has updated its safety guidelines during pregnancy which includes various benefits of exercise and other physical activity during pregnancy. These guidelines were first established about 15 years ago by Centers for Disease Control and Prevention and American College of Sports Medicine and since 9 years, they have been adopted by the American College of Obstetricians and Gynecologists.

Experts say that these new guidelines have improved their understanding related to the amount and intensity of physical-activity required to improve health outcomes and quality of life.

These guidelines suggest that pregnant women between the age of 18 and 45 years can perform 8 to 10 muscular strength exercises, once or twice a week. On aerobic training session during the period of pregnancy could be replaced by a muscle strengthening session in the weight room or at home.

The guidelines recommend the use of lighter weights with more repetitions rather than heavy weights, as they can overload joints which are loosened by the increased levels of the hormone relaxin during pregnancy.

Gerald S. Zavorsky, PhD, Director of the Human Physiology Laboratory at Marywood University in Scranton, Pennsylvania, said that pregnancy is not the time to reduce weight but muscle strengthening exercises could help them in reducing weight and burning calories.