Myths and Facts: Exercising While Pregnant

Busting the myths about exercising while pregnant

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I'm eight months pregnant with my first baby. I can't believe that my life is about to change forever. Overall, I'm excited about the transition to parenthood, and I'm ready to deal with the good, the bad, and the ugly. While I've received some fabulous advice from moms, I've also received some warnings that soon I will start putting myself last.

Rebecca Scritchfield
Rebecca Scritchfield
That news has been a tough pill to swallow because self-care is a major part of my identity. This includes making "me time" for eating well, exercising, and managing stress. I'm mentally committed to preserving that identity while I make room for baby. Throughout my pregnancy, I've followed this guiding principle: "Everything you do for you, you do for the baby inside you." This line of thinking has increased my motivation for self-care, not decreased it.

Since getting pregnant, I've logged an estimated 800 miles in running (that's the distance of over 30 marathons) and participated in four races—one half marathon, a 5K mud run, and two 5-mile trail races. Add in my swimming, strength training, and yoga, and I'm pretty confident I've maintained my vigorously active lifestyle during my pregnancy.

However, I have found that most of the pregnancy books out there seem to emphasize the "negatives" you may experience in pregnancy. They advise minimal exercise and feature line drawings of pregnant women who, in my opinion, look absolutely miserable. Meanwhile, I have met many physically active women who say that pregnancy has caused them to decrease their exercise regimen or stop altogether. They may explain the decision by citing their own concern or those of their partners and relatives or lack of encouragement from a doctor.

This news is very discouraging to me, because I have found that remaining active during pregnancy brings many benefits to both mom and baby. There is misinformation out there that needs to be addressed, and that is exactly what I hope to do in this post.

Please share this post with everyone you know who is pregnant or thinking about becoming pregnant.

Myth or Fact: Women should not try any new exercise regimen once pregnant.

MYTH. Although obstetricians typically recommend that pregnant women don't add new exercises to their regimen, there isn't any evidence to show such advice is warranted. The key to any good exercise program is a variety of activities, with cardiovascular endurance, strength, and flexibility components. Keep doing what you love (running in my case), but try to introduce one additional component—like using the elliptical machine or swimming—in case you need another option later on in pregnancy. There really isn't a need to abruptly increase your amount of activity once pregnant. You can start a strength training program focused on developing your upper body and modify it as your pregnancy advances. If you don't have any experience with strength training, start out with light weights and seek a trainer who specializes in prenatal exercise.

Without question, flexibility should be part of everyone's training program, yet it's rarely included. Now is the time. For your flexibility training, do yoga, especially prenatal yoga. You don't have to have any experience with yoga before pregnancy to start. Find a prenatal class, or look for yoga classes that are recommended for pregnant women. An introductory yoga class taught by an instructor certified in prenatal yoga would likely be just fine when prenatal classes aren't available. Be sure to tell the instructor you are pregnant, even if it seems obvious. Soon enough, you will learn the modifications, and you'll know what feels good and doesn't on your growing belly. As the pregnancy progresses, the prenatal classes become even more beneficial as you practice breathing, vocal toning, and squats—lots of squats.

Myth or Fact: The shortness of breath women experience during pregnancy is a sign that they shouldn't exercise.

MYTH. The shortness of breath that women experience in pregnancy is actually due to elevated levels of the hormone progesterone, which stimulates breathing and improves the transfer of gasses between mom and baby. Women "feel" short of breath, but their lung capacity remains normal. In fact, exercise helps to build a larger and more vascularized placenta (the fetal "lung"), which helps protect the baby from oxygen deprivation and allows more nutrients to get to the baby.

Myth or Fact: Women should exercise right up until labor.

FACT. Some of the best outcomes associated with exercise during pregnancy occur when activity continues as late into the pregnancy as possible. Documented benefits include: reduced risk of premature labor and very small birth weights; substantially decreased need for operative intervention and pain management during labor; shorter labor, and less weight gain during pregnancy. Of course, any medical restriction of exercise takes priority. However, if you aren't restricted, there is no reason to cut back. You may need to adjust the intensity or duration or take a rest day if you are really not feeling it. But don't quit.

Myth or Fact: Women should not do vigorous exercise, because the risk of overheating puts the baby at risk.

MYTH: Pregnancy actually reduces the risk of the mother's body temperature getting high enough to bother the baby, because she has an increased ability to get rid of excess heat (through increased blood volume and sweating at lower temperatures) or store it (as mom gains weight, the tissue needs to be kept warm). These combined forces allow pregnant women who are physically active to better manage heat stress than non-exercisers. Of course, don't run outside at the hottest, most humid time of day. The key is to ensure adequate air flow and ambient temperature. If exercising indoors, make sure there is good ventilation with air conditioning, fans, or open windows that allow for cooler temperatures and circulation. Don't forget to hydrate every few minutes during all exercise.

Myth or Fact: Women who exercise throughout pregnancy may improve the short- and long-term health of their baby.

FACT: In the short term, studies show the babies of exercising moms tolerate the stresses of labor and delivery better than babies of non-exercising women. One-year-old children of exercising moms were shown to perform significantly better on the standardized Bayley Scales of Infant Development when compared to non-exercising moms, according to James Clapp and Catherine Cramm in their book, Exercising Through Your Pregnancy. At five years of age, there was no evidence that vigorous exercise throughout pregnancy caused any harm in the baby's physical or mental development. Plus, the 5-year-old children of exercising moms tended to weigh less than the children of women who did not exercise during pregnancy.

What Now? No matter where you are in your pregnancy, it's a good time to check in with yourself to make sure you are at least moderately active—around 30 minutes three times a week. If you are catching flak from anyone but your prenatal care provider, make sure they understand the myths and facts on the subject and trust yourself. Seek the assistance from qualified experts in prenatal care, such as your doctor, midwife, doula, trainer, yoga teacher, and sports coach. Have fun, and remember: Everything you do for you, you're doing for baby, too.

Hungry for more? Write to with your questions, concerns, and feedback.

Rebecca Scritchfield, MA, RD, ACSM Health Fitness Specialist, helps empower people to build healthy lifestyles. A graduate of the Johns Hopkins University, Scritchfield is a Washington, D.C.-based registered dietitian and fitness expert who encourages clients to find exercise that feels great, learn to manage stress, and establish lifelong eating skills that balance individual nutrition needs with hunger and pleasure. Visit her blog at: