Exercise in Pregnancy
Now, more than ever, women are reaping the benefits of regular exercise. For many women, physical fitness and active recreation has become a way of life, but what happens when a woman becomes pregnant and wants to continue her routine of daily exercise?
- Should she discontinue exercise?
- What are the risks of exercise in pregnancy? What are the benefits?
- What types of exercise are allowed?
- What complications of pregnancy exclude exercise of any kind?
- Can a Pregnant Woman Continue to Exercise?
- How Do You Determine What is a Safe And Healthy Level of Exercise for the Pregnant Woman?
- What Precautions Should the Pregnant Woman Take When Exercising?
- How Should A Pregnant Woman Start An Exercise Program?
- What Are The Effects On The Fetus?
- What Are the Benefits of Exercise in Pregnancy?
Can a Pregnant Woman Continue to Exercise?
- The majority of women who desire to continue their exercise routine during pregnancy are motivated by the desire to achieve the health benefits of it and maintain muscular and cardiovascular fitness.
- A smaller segment of these women train intensively, seeking to improve performance. For most healthy women with an uncomplicated pregnancy who engage in a moderate level of physical activity, fitness can be maintained throughout pregnancy and in the postpartum period.
- Women who have achieved cardiovascular fitness prior to pregnancy should be able to safely maintain that level during pregnancy.
- The goal of exercise should be to maintain a sense of wellbeing and fitness, NOT to curb weight gain or competitively train. Those women who are interested in maintaining performance need closer follow-up with their healthcare providers.
How Do You Determine What is a Safe And Healthy Level of Exercise for the Pregnant Woman?
- The physiologic and mechanical changes of pregnancy will decrease the subjective workload (how hard you can work out) and maximum exercise performance (and your maximum effort).
- A woman shouldn't seek to increase her level of fitness or start a new, rigorous exercise program when pregnant.
- Women can continue in most programs that were started before pregnancy.
As when not pregnant, listen to your body. It will tell you when enough is enough. "No pain, no gain" is not the motto for exercise in pregnancy. There is no reason to limit the duration of exercise or target heart rate in pregnancy, but be aware that one's level of energy and reserves will slowly decline as pregnancy progresses, and there may be a need to alter training accordingly.
- A woman can continue in either weight bearing (running, dance or step aerobics) or non-weight-bearing (cycling or swimming) aerobics.
- Non-weight-bearing exercises will minimize the risk of injury and may assure the continuation of exercise during pregnancy. Studies have shown that women who participate in non-weight-bearing exercise were more likely to continue with the same level of satisfaction throughout their pregnancy as compared to weight-bearing exercisers.
What Precautions Should the Pregnant Woman Take When Exercising?
There are some complications of pregnancy that benefit from a sedentary (inactive) lifestyle, and a woman should consult her doctor to make sure exercise is safe for her. Some of those complications are:
- Ruptured membranes -- "Water breaking"
- Premature labor -- Going into labor earlier than anticipated.
- Incompetent cervix -- The cervix begins to dilate very early in pregnancy without any contractions.
- Unexplained bleeding -- See your doctor for any unexplained bleeding.
- Placenta previa -- The placenta is attached low on the uterine wall near the internal os (the opening to the cervix). The placenta can begin to pull away from the wall of the uterus and cause unexplained and painless, bleeding-usually in the third trimester.
- Multiple pregnancy -- Expecting twins or more.
Most of the same practices that apply when not pregnant are appropriate for the expectant mother. Because of the increased needs of the developing baby, she should be particularly careful to maintain an adequate diet.
- In addition to the increased caloric needs of the specific exercise regime, an additional 300 calories per day are required the meet the metabolic needs of pregnancy.
- Lower fasting blood glucose levels are the rule in pregnancy, so guarding against hypoglycemia (low blood sugar) with adequate carbohydrate intake is essential.
- The risk of dehydration (not having enough fluids, especially water) is increased during exercise in the pregnant women. Drink plenty of water-at least eight glasses a day and more when it's hot. Drinks with caffeine or alcohol dehydrate, or remove, water from your body.
- Those who were previously sedentary (inactive) may safely engage in exercise programs modified to be low risk for injuries. There are many aerobic programs geared towards pregnant women and led by instructors who have been specifically trained in the special needs of the pregnant athlete.
- The expectant mother should be careful during activities where a loss of balance could harm her or the baby because her center of gravity will continually shift as pregnancy progresses. Keeping her balance becomes harder over time.
- This change also puts more strain on the lower back, often resulting in greater hip and sciatic pain (the nerve that runs from your back down the back of your legs)
- Biomechanical changes of pregnancy result in connective tissue laxity (or looseness), making your joints more unstable and prone to injury.
It is normal for energy levels to decrease as pregnancy advances and therefore tolerance for exercise is lowered. Women should be encouraged to alter their routine based on how they feel. Naps are a good thing! This is not the time to push exercise to exhaustion.
To provide adequate blood flow to both baby and mother, avoid activities that require lying flat on your back. There is a large vein (the vena cava) that brings blood back to the heart that can be compressed by the enlarging uterus. This position (lying flat on your back) can:
- Reduce your blood pressure
- Decrease the blood flow to the baby
How Should A Pregnant Woman Start An Exercise Program?
As mentioned, women who are currently exercising and are without pregnancy complications can continue their routine program following the points listed above. Pregnancy is not a time to begin an intense exercise program.
- For women who have not regularly engaged in aerobic exercise, activities such as swimming, walking or cycling done at a mild to moderate pace are acceptable.
- Progress should be made gradually under the guidance of your healthcare provider. A discussion of your exercise routine with your healthcare provider is always a good idea.
What Are The Effects On The Fetus?
Exercise has the potential to cause uterine contractions or precipitate (hasten) preterm labor in women at risk for this complication.
Most studies show that in the majority of healthy pregnant women without additional risk factors for preterm labor, exercise does not increase either baseline uterine contractions or the incidence of preterm labor or delivery.
During exercise there is a decrease in the blood flow to the uterus and placenta. The result of this decrease is lessened by the physiologic changes in pregnancy:
- Increased blood volume
- Increased cardiac output
- Decreased resistance to blood flow
- Increased oxygen extraction by the placenta
This highlights the importance of maintaining adequate hydration to preserve the increased blood volume in pregnancy. A decrease in birth weight has been demonstrated in some studies of women who exercise at high intensities during pregnancy.
For the recreational athlete, this is not a concern. There were no short- or long-term deleterious (harmful) effects in those infants who had a reduction in birth weight (10-12 ounces).
What Are the Benefits of Exercise in Pregnancy?
Studies have suggested that women who exercise during pregnancy may have:
- Shorter labor
- Fewer Cesarean deliveries
- Less fetal distress
- The most important benefit is an overall feeling of well being
Women who exercised reported feeling an enhanced self-image, a reduction in minor discomforts of pregnancy, and fulfillment of their need for exercise.
Exercise in an uncomplicated pregnancy is safe and holds many benefits for the expectant mother without any known risks. Spontaneous miscarriage occurs in about 15-25% of known pregnancies and is rarely, if ever, due to the maternal stress of exercise. Every woman, with the counsel of her obstetrician/gynecologist, can maintain fitness during pregnancy.
- Follow a mild to a moderate exercise routine.
- Avoid exercise that calls for lying flat on your back.
- Modify the intensity according to your level of fatigue and avoid exhaustion
- Non-weight-bearing exercise will reduce the chance of injury and has the greatest chance of continuance during pregnancy.
- Avoid activities that require excellent balance as the pregnancy progresses.
- Maintain hydration (that is, drink plenty of water. Drinks with caffeine or alcohol dehydrate, or remove water from, your body.)
- Eat a diet that meets the needs of you and your growing fetus and takes into account the exercise you are doing.
- Most of the changes of pregnancy last for 4-6 weeks after delivery.
- Consult your obstetrician/gynecologist early in your pregnancy regarding continuing or initiating an exercise program.
For more information:
Go to the Pregnancy
health topic, where you can:
- Read articles on this topic
- Browse the previously asked questions
Last Reviewed: Apr 23, 2002
Thomas A deHoop, MD
Formerly Associate Professor of Clinical Obstetrics and Gynecology
Director, Medical Student Education
No longer associated