If you want to stir up some controversy, just make a statement about what a mom-to-be should (or should not) do in terms of exercise while she is pregnant. Arguments ranging from “Crossfit for every pregnant mama!” to “everyone knows pregnant women need to rest and relax” abound. In 2011, a recreational runner gave birth to a healthy baby just hours after finishing the Chicago marathon, and more recently, another woman made the news when she finished the Boston Marathon at 34 weeks pregnant. The media loves to talk about controversial accomplishments of moms-to-be, so it is important for pregnant women and those they rely on for support to know what is safe and what is not.
So, let’s sort out the myths from the truth. But first, let me offer this disclaimer. I have a PhD in Exercise Physiology and studied with one of the most well-known experts on exercise during pregnancy in the world. I did my dissertation research on the topic of exercise during pregnancy, and I continue to study and publish in this area as a faculty member at the university where I now work. However, I am not a medical doctor. Please always consult your healthcare provider on matters related to your health, which include exercise and being physically active during pregnancy.
Below are ten things you should know about exercise and physical activity during pregnancy. Please note that unless otherwise specified, the information cited below is from the American College of Obstetricians and Gynecologists (ACOG) 2015 Committee Opinion on Physical Activity and Exercise during Pregnancy and the Postpartum Period.
10 Things You Need to Know About Exercise During Pregnancy and Postpartum
Exercise during pregnancy is (generally) both safe and beneficial for the mother.
Women who are pregnant enjoy a number of benefits from regular physical activity or exercise during pregnancy. These include lowered risk of gestational diabetes (a type of diabetes than can develop during pregnancy), lower risk of requiring a Cesarean delivery, and decreased recovery time postpartum. Obviously, exercising regularly during pregnancy does not guarantee any particular outcome for the mother or her baby, but risk of unfavorable outcomes is indeed lower.
Exercise during pregnancy is (generally) both safe and beneficial for the baby.
It’s not just the mamas who reap the benefits of exercising during pregnancy — babies seem to gain an advantage too. Babies born to mothers who were active tend to be slightly smaller (in a good way) and leaner than babies born to women who did not exercise (citation here), and some studies indicate a small but reduced risk of pre-term birth in offspring born to active mothers (citations here and here).
Moderate-intensity activity is recommended for (almost) everyone.
The physical activity recommendations for pregnant women are actually the same as they are for the general population — which is a surprise to a lot of people. Whether you’re pregnant or not, you should accumulate 150 minutes per week of moderate-intensity activity. A good way to determine whether an activity is “moderate” is to use what we call the Talk Test. If your heart rate is elevated and you are breathing more heavily than usual, but can talk through the activity, it’s probably moderate in intensity. If you are unable to talk normally because you are out of breath, the activity is probably vigorous, the next category of physical activity intensity.
Importantly, there are a few rare circumstances in which no activity is safe. Any healthcare provider should make it abundantly clear that physical activity is a no-no if you have one of these conditions (i.e. bed rest would be prescribed, most likely): severe hypertension (high blood pressure), ruptured membranes, and premature labor. Typically it’s pretty obvious to avoid exercise, but for those interested, you can find a full list here.
Walking is great exercise for pregnant women.
Walking is the most commonly utilized exercise among pregnant women. In fact, it’s the most commonly utilized exercise among all people. If you’re unsure what is safe during pregnancy, you are feeling very sick and/or tired, or you’ve never been a regular exerciser, walking is a great way to stay healthy. A brisk walk can reduce fatigue and is quite safe for the vast majority of pregnant women. A 30-minute walk is ideal because it will help you to meet the physical activity guidelines mentioned above, but any activity is better than none.
Vigorous (high) intensity exercise should be reserved for the mama who was already highly active before she became pregnant.
Research suggests that high-intensity activity is safe provided that the woman was engaging in those types of activities before she became pregnant, and that she does not have any health conditions that would warrant avoiding activity (see the list linked above for a comprehensive listing of these conditions). So while a woman who has never been an exerciser should not start marathon training when she becomes pregnant, a woman who has run many marathons can continue to run, even long distances, provided that she is healthy and is not having pregnancy complications. Again, see your healthcare provider if you have questions or concerns.
Avoid crunches or exercises that require lying on your back after the first trimester.
There aren’t too many activities that pregnant women should avoid, but there are a few. The first is to stay away from exercises that involve lying on your back after the first trimester. This is for the same reason that it is recommended to avoid sleeping on your back later in pregnancy — blood flow is reduced to the placenta in this position. You can still do abdominal exercises like crunches, but you should do a modified version lying on your side.
Pregnant women should do no scuba diving or contact sports.
Sorry, no scuba diving during pregnancy. The drastic pressure changes are dangerous for the developing fetus and should be avoided. Further, pregnant women should avoid contact sports (such as basketball or soccer) and activities where the risk of falling is great (like ice skating, snow skiing, and water skiing).
Resistance exercise seems to be safe during pregnancy.
We know far less about resistance exercise (such as lifting weights or using resistance bands) during pregnancy, but the limited research evidence suggested that it is safe. One study (see here) found that engaging in resistance training during pregnancy did not result in any adverse birth outcomes such as preterm birth or need for Cesarean delivery. Similarly, other studies have found that second trimester resistance training does not impact birth outcomes (see here) and other data suggests that light resistance training in the second and third trimester does not affect birth size or mode of delivery.
Postpartum return to exercise depends upon mode of delivery and presence of complications.
There isn’t much information available about exactly when a woman may return to exercising after giving birth. The ACOG Committee Opinion states that some women can return to their activities “within days of delivery” but that return to activity also depends on how the woman delivered (vaginally versus Cesarean) and whether there were any complications. Don’t be afraid to call your healthcare provider and ask, especially if you desire to start being active earlier than your six- or eight-week postpartum check-up.
Exercise is safe for breastfeeding women and does not affect milk supply.
Research suggests that women who are breastfeeding can engage in their regular exercise or physical activity without concern for milk supply. Be sure to stay hydrated by consuming plenty of water, however.
Overall, exercise and physical activity is both safe and beneficial during pregnancy, but there are some important changes to be aware of when you become pregnant. When in doubt, check with your healthcare provider about your questions or concerns, and have a happy, healthy pregnancy!