The facts about exercise and pregnancy

Moderate-intensity exercise during pregnancy is not only safe when cleared by a medical provider, it’s strongly recommended. Like other healthy adults, pregnant women should get 150 minutes of aerobic physical activity each week. Regular exercise can help relieve back pain and promote healthy weight gain. It might even reduce your risk of developing gestational diabetes and preeclampsia (high blood pressure and protein in your urine). Still, if you exercised regularly before you were pregnant, you might need to make some changes to make sure your workouts are safe.

How much to exercise while pregnant

Healthy pregnant women should get about 30 minutes of exercise each day, totaling at least 105 minutes a week of moderate-intensity aerobic exercise (brisk walking, light jogging, swimming). Exercising when you’re pregnant helps reduce your risk for excessive weight gain (more than 35 lbs. for women with a BMI of 18.5–24.9), gestational diabetes, and postpartum depression. If you already do vigorous-intensity exercise (running or jogging, swimming laps, fast biking), you can continue at that level as long as you stay healthy and check with your healthcare provider about when to adjust your activity level.

Remember, your body changes with pregnancy, so you may need to work harder to do the same exercises pregnant you did before you were pregnant. Try not to get frustrated, and don’t overdo it. While you’re pregnant, avoid exercises that increase the risk of falling or require stomach-down positions, with the exception of swimming. You should also avoid being on your back for extended periods of time. For example, sit-ups or supine bench presses should be limited because of the risk of cutting off blood flow to the fetus.


The most important thing is to listen to your body, don’t ignore pain or fatigue, and talk to your healthcare provider if you have any concerns.


Lifting weights during pregnancy

The safety of resistance training—lifting weights to improve muscular strength or endurance—during pregnancy is a little less clear than for aerobic training. In occupational settings, where women are lifting moderately heavy loads consistently through pregnancy, women have an increased risk of preterm labor, or going into labor earlier than 37 weeks. Light- to moderate-intensity resistance training 2–3 times a week doesn’t seem to carry the same risk as occupational lifting, however. It has been shown to help manage back pain and fatigue, and increase energy, especially when combined with aerobic training. The bottom line for resistance training during pregnancy is that you should get cleared by your medical provider before starting a new routine. If possible, consult a strength and conditioning professional to help plan your training.

Postpartum exercise—exercising after your baby’s birth

Daily exercise in the postpartum period (6–8 weeks after delivery) has many benefits, including less fatigue, and increased fitness and motivation. It might even reduce the onset of depression (as long as the exercise relieves your stress rather than causes it).

Some women are concerned exercise could decrease their milk supply. But women who work out regularly, stay hydrated, and eat enough to meet their calorie needs continue to produce enough breast milk. The composition of breast milk stays the same with moderate-exercise intensity (about 50–70% of your maximum heart rate), but vigorous exercise (roughly 70–85% of your maximum heart rate) can cause lactic acid to appear in milk, which could affect how well your baby accepts your milk. So consider nursing your baby before you do any intense workouts, or wait for a few hours after an intense workout before you nurse again to allow your body to clear the lactic acid.

Since everyone recovers differently, returning to physical activity after giving birth depends on the person. Be sure to discuss your exercise habits and plans with your doctor before going back to your pre-pregnancy workout routine.

In the meantime, visit the American College of Obstetricians and Gynecologists website to learn more about exercise during pregnancy and in the postpartum period. Chapter 6 of the 2018 Physical Activity Guidelines for Americans also provides good information about the benefits of exercise during and after pregnancy. Stay healthy for you and your baby!


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References

Cai, C., Vandermeer, B., Khurana, R., Nerenberg, K., Featherstone, R., Sebastianski, M., & Davenport, M. (2020). The impact of occupational activities during pregnancy on pregnancy outcomes: A systematic review and metaanalysis. American Journal of Obstetrics and Gynecology, 222(3), 224–238. doi:10.1016/j.ajog.2019.08.059<

Committee on Obstetric Practice. (2019). Committee opinion: Physical activity and exercise during pregnancy and the postpartum period. Retrieved 9 March 2020 from https://www.acog.org/-/media/Committee-Opinions/Committee-on-Obstetric-Practice/co650.pdf?dmc=1&ts=20200309T1437183780

Perales, M., Santos-Lozano, A., Ruiz, J. R., Lucia, A., & Barakat, R. (2016). Benefits of aerobic or resistance training during pregnancy on maternal health and perinatal outcomes: A systematic review. Early Human Development, 94, 43–48. doi:10.1016/j.earlhumdev.2016.01.004

van Beukering, M. D. M., van Melick, M. J. G. J., Mol, B. W., Frings-Dresen, M. H. W., & Hulshof, C. T. J. (2014). Physically demanding work and preterm delivery: A systematic review and meta-analysis. International Archives of Occupational and Environmental Health, 87(8), 809–834. doi:10.1007/s00420-013-0924-3

Ward-Ritacco, C., Poudevigne, M. S., & O’Connor, P. J. (2016). Muscle strengthening exercises during pregnancy are associated with increased energy and reduced fatigue. Journal of Psychosomatic Obstetrics & Gynecology, 37(2), 68–72. doi:10.3109/0167482x.2016.1155552