Exercising during Pregnancy: anything goes?

Laurén A. Doamekpor

January, 2014

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In September, 2013, Lea-Ann Ellison, (pictured) a 35-year-old mother of two from California, gained widespread media attention for pictures posted on Facebook of her lifting weights two weeks before her due date. Ms. Ellison was doing a crossfit workout, a popular strength training and intensity fitness program that she had started almost two years prior to becoming pregnant. Her pictures, which included her doing an overhead squat holding a weighted barbell, pull-ups and kettlebell swings, provoked a storm of comments. Some admired her dedication to fitness and others were critical of her, wondering if she was endangering her baby. Although Ms. Ellison gave birth to a healthy baby boy, her fitness regimen brings up important questions about how much and what kinds of exercise are safe to do while pregnant.

In general, staying physically active during pregnancy is good for you: it lowers your risk of heart disease, helps keep you from gaining too much weight, and it makes you feel good!1 Gaining too much weight during pregnancy can increase the chances of gestational diabetes (diabetes that is first diagnosed in a pregnant woman who did not have diabetes before becoming pregnant) and of having a cesarean or preterm delivery.2 Pregnant women, like all women, should get at least two and a half hours of moderate-intensity activity such as fast walking every week, or an hour and 15 minutes of vigorous-intensity aerobic activity such as running.3

But for pregnant women, how much exercise is too much? And what kinds of exercises should you avoid if you are pregnant?

The U.S. government has a set of physical activity guidelines for pregnant women, and the American Congress of Obstetricians and Gynecologists (ACOG), which is the medical society for OB/GYNs, also provides advice. Unfortunately, most of the research available on the risks of exercising during pregnancy is based on studies with very small numbers of women, with each study defining and measuring exercise in different ways. A 2005 review of studies on exercise during pregnancy stated that overall, moderate exercise during a pregnancy that is not considered “high-risk,” did not harm mothers or infants and improved mothers’ overall fitness and health. In those pregnancies, physical activity does not increase the chance of early delivery, low-birth weight, or early pregnancy loss.4

What do we know about exercising during pregnancy?

  • It’s good for you and your baby:
    • Unless your doctor has told you not to exercise, exercising during pregnancy can: decrease your chances of developing pregnancy-related high blood pressure or gestational diabetes 5, help control the amount of weight you gain during your pregnancy, help you sleep well, and boost your energy.6
    • It will also reduce the chance that your baby will be born larger than normal. Women with gestational diabetes or who gain more weight have larger than normal babies.6
  • It’s important to get the green-light from your doctor:
    • If you have certain health issues such as vaginal bleeding, certain forms of heart or lung disease, or have high blood pressure, diabetes, or other conditions that put your pregnancy at risk, your doctor may advise you not to exercise.6
  • The guidelines you need to follow during pregnancy depend on whether you are a beginner or someone who has been exercising for a long time:
    • Healthy non-exercisers: Begin a moderate-intensity aerobic workout such as brisk walking for up to 150 minutes per week. Do not begin a vigorous exercise routine such as running.7
    • Women who regularly exercised and did vigorous, high-intensity workouts or strength training before becoming pregnant: As long as you are healthy and feeling up to it, continue your workout routine.7
    • Whether you are a beginner or not, staying hydrated and making sure that your body temperature does not rise too high during your workout is important. Higher than normal body temperatures during pregnancy have been linked to birth defects.8 Although a fetal medicine physician at New York University Medical School featured in a New York Times article in 2014 recommends that pregnant women avoid raising their body temperatures above 100 degrees Fahrenheit,9 this recommendation was removed from the ACOG guidelines 20 years earlier because of lack of evidence.
  • There are some exercises you should avoid no matter how fit you were before you got pregnant:
    • After the first trimester, avoid doing exercises that involve lying on your back, because this position may lower your heart rate and reduce the amount of oxygen in the blood that goes to your baby. Also avoid exercises that may increase your chances of falling or injuring your belly, such as horseback riding, soccer, and basketball.7
    • ACOG  states that exercise at altitudes of  6000 feet and lower appears to be safe, but exercise at higher altitudes may result in lower oxygen consumption, which may harm the baby.10 11
  • There are symptoms that warn a pregnant woman to  stop exercising.
    • ACOG recommends that pregnant women should stop exercising if they experience one or more of the following10:
      • Headache
      • Dizziness
      • Muscle weakness
      • Vaginal Bleeding
      • Racing heart beat or chest pain

Bottom Line

If you have a healthy pregnancy, exercising is recommended and staying active will help you feel good. If you were fit and had an exercise routine before getting pregnant, chances are you can maintain that routine if your pregnancy is routine Remember to get advice from your doctor before you start any exercise routine, and keep track of how you feel or any symptoms you experience as you work out.

  1. Centers for Disease Control and Prevention. Physical Activity and Health. Available at: http://www.cdc.gov/physicalactivity/everyone/health/. Accessed December 2, 2013.  
  2. Centers for Disease Control and Prevention. Reproductive Health. Available at: http://www.cdc.gov/reproductivehealth/maternalinfanthealth/pregcomplications.htm. Accessed January 14, 2013.  
  3. U.S. Department of Health and Human Services. Physical Activity Guidelines for Americans. Available at: http://www.health.gov/paguidelines/guidelines/summary.aspx. Accessed on December 4, 2013  
  4. Morris SN, Johnson NR. Exercise During Pregnancy. J. Reprod. Med. 2005;50: 181-188.  
  5. Dempsey JC, Sorensen TK, Williams MA, et al. Prospective study of gestational diabetes mellitus risk in relation to maternal recreational physical activity before and during pregnancy. Am J Epidemiol. 2004;159:663–70.  
  6. Mayo Clinic. Available at: http://www.mayoclinic.com/health/pregnancy-and-exercise/PR00096. Accessed on December 10, 2013  
  7. Physical Activity Guidelines Advisory Committee. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services; 2008.  
  8. Artal R, M. O’Toole. Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period. British Journal of sports medicine. 2003; 37(1): 6-12.  
  9. O’Connor A. The New York Times. Pregnant Weight Lifter Stirs Debate. http://well.blogs.nytimes.com/2013/09/24/pregnant-weight-lifter-stirs-debate/?_php=true&_type=blogs&_r=0.  
  10. Exercise during pregnancy and the postpartum period. ACOG Committee Opinion No. 267. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2002;99:171–17  
  11. Artal R, Fortunato V, Welton A, Constantino N, Khodiguian N, Villalobos L, Wiswell R. A comparison of cardiopulmonary adaptations to exercise in pregnancy at sea level and altitude. American Journal of Obstetrics and Gynecology. 1995;172(4):1170-1180.