Everyone should exercise … including women who are pregnant and expecting. It’s good for you. It’s good for the developing baby. It promotes overall good health and a better quality of life. Exercise and physical activity have few risks and multiple rewards when it comes to (an uncomplicated) pregnancy. But one should keep in mind that pregnancy is not the time to improve your physical fitness. The goal of a physical fitness and exercise program during pregnancy should be to ensure a good quality of health of the mother and the proper growth and development of the baby.
The American College of Sports Medicine (ACSM) recommends the following to promote good health in all adults:
Cardiorespiratory Exercise: Adults should get at least 150 minutes of moderate-intensity exercise per week.
Resistance Exercise: Adults should train each major muscle group two or three days each week using a variety of exercises and equipment.
Flexibility Exercise: Adults should do flexibility exercises at least two or three days each week to improve range of motion.
Neuromotor Exercise (a.k.a. “functional fitness training”): Adults should do neuromotor exercise two or three days per week.
Although there are few risks associated with exercise in pregnancy it is important to know the risks and modify the activities as needed. According to the American College of Obstetricians and Gynecologists (ACOG), there are several considerations for expecting mothers and as it relates to their participation in physical exercise:
- Weight gain
- Low back pain
- Laxity of joints
- Increase in body temperature
- Energy balance
- Decreased blood flow in supine positions
As a woman’s body weight increases during pregnancy, more stress is put on the joints (especially the hips and knees). During an activity like running, the hips and knees can experience upwards of a 100% increase in joint stress. Such large forces can cause joint discomfort and/or pain and increase damage to arthritic or unstable joints. Alternative choices for cardiovascular exercise would include lower impact exercise (elliptical trainer, recumbent bike) or water-based activities (water aerobics, water jogging).
Low Back Pain
Because of the anatomical changes that occur during pregnancy, upwards of 50% of pregnant women experience low back pain as a result of lumbar lordosis. Avoid exercises that compromise the lower back and include exercises that strengthen the core stabilizing muscles (rectus abdominis, internal and external obliques, transversus abdominis, pelvic floor muscles and erector spinae).
Laxity of Joints
Two hormones (estrogen and relaxin) are released at higher levels to promote the relaxation of ligaments in the pelvis. This occurs to prepare the body for the birth of the baby. They are released in higher amounts during the first 14 weeks of the first trimester and also at delivery. Avoid prolonged exercise that stretches or puts pressure and force on the joints (running, tennis, over stretching).
Increase in Body Temperature
During pregnancy a woman burns more calories and generates more heat than those who are not pregnant. Because it only takes a few degrees to overheat (which can be dangerous for both mother and baby) it is important to monitor the duration and intensity of exercise and stick to climate-controlled (air conditioned) environments. Recommendations for cardiovascular exercise include sessions that don’t exceed 45 minutes. Sessions of 15 to 20 minutes (adding up to 45 minutes) are recommended for women who are new to exercise during their pregnancy.
During pregnancy a woman will increase her energy requirements by 3,000 calories per day (or more) in the second and third trimesters. If they are physically active they will need to further increase the amount of food they eat to make up the difference. This will ensure the baby gets enough nourishment for healthy growth.
Decreased Blood Flow in Supine Positions
After the first trimester, lying down flat on your back (supine position) results in an obstruction in the blood returning to your heart. This position should be avoided as much as possible at rest and during physical activity. Examples of supine exercises include bench press, mat pilates (without modifications) and standard sit ups.
Final Thoughts – Exercise and Pregnancy
Pregnancy shouldn’t be viewed as a state of confinement. Pregnant women with uncomplicated pregnancies should be encouraged to continue and engage in physical activities. Regardless, pregnant women should seek the advice of their obstetrician or gynecologist before starting any exercise program. All active pregnant women should be examined periodically to assess the effects of their exercise programs on the developing fetus, so that adjustments can be made if necessary.
For more information on the American College of Obstetricians and Gynecologists’ recommendations, click here. For more information on the American College of Sports Medicine’s current comments on exercise during pregnancy, click here.