Exercise During Pregnancy

Guidelines Revised

Many mothers-to-be are concerned with the physiological toll that their body will go through during pregnancy. They may wish to initiate an exercise program to prepare their body for the pregnancy. Other mothers-to-be, who already participate in regular physical activity, may wish to continue their healthy active lifestyle during pregnancy. For these reasons the American College of Obstetrics & Gynecology (ACOG) developed guidelines in 1984 for exercising during pregnancy. These guidelines have just recently been revised. The original ACOG guidelines limited the mother’s heart rate to 140 beats per minute and the duration of steady state exercise was not to exceed 15 minutes. These guidelines were established in order to prevent the mother’s core temperature from exceeding 100°F and to insure that blood flow would not be shunted away from the fetus.

The new ACOG guidelines are less clearly defined in terms of heart rate and duration. However, the ACOG now recognizes the differences between women who regularly exercise and become pregnant and women who start exercising during pregnancy. Now, if a woman has exercised consistently before pregnancy, she is advised that she can continue her training during pregnancy. On the other hand, if a woman has not exercised before pregnancy, a significant exercise program is not recommended. Those who do begin exercising after becoming pregnant are advised to receive physician authorization and exercise at low-intensity and engage in low or non-impact activities (e.g. walking and swimming).

The remainder of the new guidelines include some of the old guidelines.
Briefly, the remainder of the new guidelines:

1. High-impact, physical contact, or ballistic movements should be avoided.
2. Prolonged aerobic exercise should be avoided (e.g. marathons and triathlons).
3. Exercise to the point of fatigue or exhaustion should be avoided.
4. Exercise in the supine position should be avoided after the fourth month.
5. Activity in which balance is a significant component should be avoided after the sixth month.
6. The activity should include an adequate warm-up and cool-down period.
7. Adequate dietary intake should be consumed in order to compensate for both the extra calories required during exercise and the extra 300 calories per day required during pregnancy.
8. Exercise should take place in a cool place and less humid environment (e.g. 68°-72° F, Humidity<60%, cool loose-fitting clothing, and drink adequate fluids).

In any situation the physician should be made well aware that the mother-to-be is considering to either continue or to start exercising during her pregnancy. This is important because the individual mother-to-be may have medical or obstetric complications which may put an otherwise healthy pregnancy at risk. Additionally, the physical changes caused by pregnancy last four to six weeks postpartum.

References:

• American College of Obstetricians and Gynecologists. Exercise during pregnancy and the postpartum period. ACOG (Technical Bulletin #189). Washington, DC: ACOG, 1994.
• American College of Sports Medicine. Guidelines for exercise testing and prescription. (5th edition) Baltimore, MD: Williams and Wilkins, 1995.

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