Exercise during pregnancy

Exercise is good for healthy pregnant women. The American College of Obstetricians and Gynecologists recommends 30 minutes or more of moderate exercise a day for most, if not all, days of the week for healthy pregnant women receiving prenatal care.¹

Exercise can improve your posture, relieve back pain and other discomforts related to pregnancy, and prepare you for the challenges of childbirth. Most women can begin or continue to exercise during pregnancy. Try exercise classes designed specifically for pregnant women or classes that offer safe variations for pregnant women. Many pregnant women find exercising in the water, such as swimming or water aerobics, most comfortable.

Maintain your prepregnancy level of fitness

In the early stages of pregnancy, some women can continue their prepregnancy exercise routines (including running, aerobics, biking, roller-skating, skiing, weight lifting, or other physically strenuous activities). Some women, however, find it necessary to take it easy during the first weeks of pregnancy but can return to their usual exercise after their morning sickness or extreme fatigue subsides.

While pregnant, listen to your body.

• When you're fatigued, take it easy, but don't become completely inactive. Mild to moderate aerobic exercise, such as walking, helps keep your energy up, as well as your mood.
• If you're inclined toward regular strenuous exercise, pay attention to your body's signals to gradually slow down or change your routine as your pregnancy advances.

Fuel your body

Eat a small snack or drink juice 15 to 30 minutes before you exercise. Do not exercise on an empty stomach. If you have not eaten, your body may run low on glucose, causing your liver to release substances known as ketones or ketoacids into your blood. Ketones are harmful to a fetus.

Continue to eat a balanced diet. Nonexercising pregnant women require an additional 150 to 300 calories a day. When you exercise during pregnancy, increase your caloric intake.

Stay hydrated and avoid overheating

Do not become overheated while exercising. A body temperature above 102.6F in the first trimester can harm a fetus.² Drink plenty of fluids before, during, and after exercise.² To avoid dehydration, drink up to 1cup of liquid before you exercise and drink a few ounces of liquid every 20 minutes during exercise. Continue drinking liquids during and after exercise even if you do not feel thirsty. This will help you stay hydrated.

Be careful

To prevent fetal injury, avoid sports that can involve potential contact, such as ice hockey, soccer, and basketball. Vigorous exercise above 6000ft and scuba diving can be dangerous for your fetus.¹

Unless you are a competitive athlete, avoid strenuous activity, and exercise only in moderation. You should be able to talk while you are working out. Do not exercise to the point that you feel tired.

Stop what you are doing and contact your health professional if you notice any of the following:²

• Excessive fatigue or shortness of breath
• Pain or cramping, especially in the back or pelvic area
• Vaginal bleeding or rupture of the membranes
• Dizziness
• Pounding heartbeat (palpitations) or unusual sensations in your chest
• Persistent contractions

After your fourth month of pregnancy, avoid any exercise that requires you to lie flat on your back on a hard surface, such as sit-ups and some yoga poses. The increasing size and weight of your uterus will press on the large blood vessel that returns blood from your lower body to your heart.

As your pregnancy advances (usually during the second trimester), unstable joints, an expanding abdomen, and an altered center of gravity can make you more unstable on your feet. Also, by then your uterus is mostly above the protective circle of your pelvic bones. Avoid exercises that might cause you to fall, such as skiing or roller-skating.

Swimming and brisk walking are safe exercises throughout pregnancy.

General guidelines

• Do not start a new or more strenuous exercise program without first checking with your health professional.
• Do not use exercise to lose weight.
• Avoid exercising during hot, humid weather or if you are not feeling well.
• Discontinue dangerous sports, such as horseback or motorcycle riding, water-skiing, diving, parachute jumping, or scuba diving.

There is no evidence that exercise causes miscarriage.³ However, if you have a history of repeated miscarriages, your health professional may advise you to avoid exercises that require your body to bear extra weight (such as running) during the first trimester.

Your baby will not be harmed if you can't exercise because of a complication of your pregnancy or an existing chronic illness or condition. You may be able to do simple exercises in bed, with your health professional's approval.

Citations

1. American College of Obstetricians and Gynecologists (2002). Exercise during pregnancy and the postpartum period. ACOG Committee Opinion No. 267. Obstetrics and Gynecology, 99(1): 171–173.

2. Artal R, Sherman C (1999). Exercise during pregnancy: Safe and beneficial for most. Physician and Sportsmedicine, 27(8): 51–60.

3. Katz VL (2003). Prenatal care. In JR Scott et al., eds., Danforth's Obstetrics and Gynecology, 9th ed., pp. 1–20. Philadelphia: Lippincott Williams and Wilkins.