Regular aerobic exercise during pregnancy appears to improve (or maintain) physical fitness. Although an upper level of safe exercise intensity has not been established, women who were regular exercisers before pregnancy and who have uncomplicated, healthy pregnancies should be able to engage in high-intensity exercise programs (e.g., jogging and aerobics) for less than 45 minutes with no adverse effects. They just need to be mindful of the possibility that they may need to increase their energy intake, and are careful to not become overheated.
In the absence of either medical or obstetric complications, doctors advise an accumulation of 30 minutes a day of exercise on most if not all days of the week. The Clinical Practice Obstetrics Committee of Canada recommends that "all women without contraindications should be encouraged to participate in aerobic and strength-conditioning exercises as part of a healthy lifestyle during their pregnancy."
In general, participation in a wide range of recreational activities appears to be safe. Pregnant women just need to avoid those with a high risk of falling such as horseback riding or skiing, or those that carry a risk of abdominal trauma, such as soccer or hockey.
Exercising while pregnant
A strong, healthy woman will generally have a good pregnancy outcome. Physicians recommend moderate exercise during pregnancy, including strength-training.
In the past, the main concerns of exercise in pregnancy were focused on the fetus and any potential maternal benefit was thought to be offset by potential risks to the fetus. However, more recent information suggests that in the uncomplicated pregnancy, fetal injuries are highly unlikely.
Contraindications for exercise include, vaginal bleeding, dyspnea before exertion, dizziness, headache, chest pain, muscle weakness, preterm labor, decreased fetal movement, amniotic fluid leakage, and calf pain or swelling (to rule out thrombophlebitis).