If you are an athlete or have an active lifestyle, you may have wondered: ‘Should my exercise routine change during pregnancy and breastfeeding?’ As a former division 1 athlete, I sure have. You may have seen the news about athletes who compete at the highest level during or shortly after pregnancy. Serena Williams won the Australian Open while 8 weeks pregnant. Alysia Montano ran the 800-meter race at a national meet in her third trimester. Allyson Felix won a gold medal at the World Championship in track only 10 months after delivering her baby. At the same time, you may hear concerns about intense physical activity during pregnancy. So, what is the recommendation for pregnant women who have an active lifestyle?

Benefits of Exercise

Most healthcare providers recommend exercise during pregnancy as part of a healthy lifestyle. Women who are active before pregnancy can usually continue these activities during and after pregnancy. Since everyone is different with different medical histories, ALWAYS have a discussion with your healthcare providers about what exercise is best for you.

In general, exercising during pregnancy might lower the chances of preterm delivery (birth before week 37) and low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). It might also help to lower the chance of diabetes and high blood pressure.

In addition, physical activity might help with the muscle aches of pregnancy as well as postpartum depression. Exercising in general has not been known to increase the chances of miscarriage, birth defects, or other pregnancy-related problems.

Studies looking at exercise during pregnancy have not looked at intense exercise specifically.

Level of Activity

Some changes to your routine may be needed because of normal changes in your body during pregnancy. Talk with your healthcare provider about your exercise routine. This is even more important for women who have pre-existing health conditions.

It is important to listen to your body during pregnancy. Every woman and every pregnancy is different. Your body goes through many changes during pregnancy:

• Blood volume increases
• Heart pumps harder
• Heart rate increases
• Fitness level decreases

Many women experience nausea and fatigue throughout their pregnancy making exercise more difficult and harder to maintain proper nutrition and hydration. Listen to your body, do not push it past its limits.

It is difficult to compare vigorous exercise between people. Jogging 10 miles may seem like a piece of cake for a marathon runner while it can be difficult for an Olympic lifter. For this reason, vigorous activity is most frequently defined as up to 85% of capacity. While maximum effort is difficult to measure, capacity is often described in terms of heart rate.

Another way to check your intensity level is the “talk test.” If you are breathing hard but can still have a conversation easily—but you cannot sing, that is moderate intensity. An activity would be considered vigorous if you can only say a few words before pausing for a breath.

If you were in the habit of doing vigorous exercise before your pregnancy, it can be continued for most healthy women during pregnancy according to experts. However, there is limited information on individuals who exceed the accepted 85% capacity. An upper level of ‘safe’ exercise intensity has not been established.

 In general, ACOG recommends aiming for at least 150 minutes (2 hours and 30 minutes) of moderate intensity aerobic activity spread out over a week. For most people, keeping your heart rate at or below 140 beats per minute is considered moderate intensity.

What to Consider When Exercising

Below is some general information to consider and discuss with your healthcare provider. Remember, everybody is different. Always discuss your specific exercise program with your healthcare providers, who know your specific medical history and how your pregnancy is progressing.

• Stick with what your body is used to. If you are used to long-distance running, pregnancy is not the time to turn into a power lifter.
• Stay hydrated. Drink plenty of fluids before, during and after exercising.
• Avoid overheating. Even if you are used to exercising in 90-degree heat, you may have to look for an alternative method such as air-conditioned gyms. Do not use steam rooms, hot tubs, or saunas.
• Avoid exercises lying flat on your back in the second and third trimester of pregnancy. This allows less blood flow to your womb.
• Do not engage in sports where you can fall, get injured, or get hit in the abdomen.
• Reduce weight load. Holding your breath during heavy lifts can result in baby’s heart rate slowing down. Because of this, you may have to reduce the weight.
• Allow enough time for your body to recover after each training session.
• Make sure you get enough calories. If you regularly participate in intense exercise, you might have to adjust your nutrition.
• Continue to fuel your body. Long, intense exercise can result in low blood sugar. Make sure you continue to fuel your body if you plan on exercising for over 45 minutes.
• Check with your healthcare provider before continuing or starting any supplements.
• Stop exercising if you:

  • Feel dizzy
  • Have a headache
  • Develop chest pain or swelling
  • Have muscle cramps
  • Experience vaginal bleeding
  • Have leakage of fluid
  • Feel contractions
  • Have shortness of breath before exertion.

• Call your healthcare provider with any concerns.

Postpartum and Breastfeeding

Make sure you talk with your healthcare provider about when to start exercising after birth. Exercise can be resumed slowly after delivery as soon as it is medically safe. When exercise can be resumed varies among women, with some being able to start exercising within days after delivery. This may depend on if delivery was a c-section vs. vaginal birth and any additional health problems or complications.

Healthcare providers will tell you it is important to remain hydrated while breastfeeding, especially when exercising. The amount of nutrition you need may also change depending on the level of your activity during breastfeeding.

At the end of the day, all athletes have different needs during pregnancy and after the baby is born. There is no ‘one-size-fits-all’ for exercising during pregnancy. The best thing you can do is talk with your healthcare provider and listen to your body. For more information, see our MotherToBaby fact sheet on exercising here. You can also find more information on exercise during pregnancy here.

Originally written 8/18/20, Updated 9/24/26

“I just found out I’m pregnant. Can I keep drinking my energy shake in the mornings?”
“My doctor gave me the go-ahead to work out. Okay to have a protein shake after the gym?”
“My immunity-boosting drink is a life-saver. Can I keep using it while I’m pregnant?”

These are common questions during pregnancy, and ones that we hear a lot at MotherToBaby. Perhaps you’ve wondered the same thing yourself. As teratogen information specialists, we provide facts about how a woman’s exposure in pregnancy might affect her developing baby. So, when we get questions about shakes, powders and other nutritional supplements in pregnancy, we look to the research. And that research, or lack of it, leads us to caution women against drinking that favorite nutritional shake while they’re pregnant. Here’s why:

Lack of FDA approval
Nutritional shakes and powders fall under the category of “supplements.” Supplements aren’t approved by the U.S. Food and Drug Administration (FDA) in the way that food and medicines are. The FDA does set out safety requirements for supplements, but the manufacturers are responsible for ensuring that their own products meet those requirements (kind of like a home builder inspecting their own house.) This means that shake makers and other manufacturers can put their products on the market without proving their safety, or even showing that the products actually do what they claim they will. Once a supplement is on the market, the FDA relies mostly on consumers’ reports to alert them of side effects or other problems that could lead to warnings or recalls.

This is not to say that all supplement makers are unscrupulous or careless. Many manufacturers go above and beyond the FDA requirements for safety, and stand behind the purity and efficacy of their products. But the lack of oversight has allowed supplements to wind up on shelves despite being contaminated with bacteria, pesticides or heavy metals (such as lead), or having mislabeled ingredients or amounts of those ingredients. These inconsistencies can be dangerous, especially for people who take medications that might interact with unknown ingredients, or for pregnant women who need to avoid potentially harmful additives that can affect the baby.

Lack of studies in pregnancy
Nutritional shakes often contain vitamins, herbs, plant derivatives and other goodies intended to boost energy, strengthen immunity or have other positive health effects. But these additives are often listed on the label as “herbal blends” or “proprietary blends,” meaning that the individual ingredients are not revealed. And even if they are listed individually, some of those ingredients may have been studied in pregnancy, while others have not. The lack of studies means we don’t know if they might have harmful effects on a developing baby or otherwise increase risks in pregnancy.

For example, some ingredients may be “generally recognized as safe (GRAS)” when eaten in the amounts usually found in food, but they could increase the risk of miscarriage when used at high concentrations in pregnancy. The concentration of a plant-derived ingredient can vary from batch to batch, depending on the growing and harvesting conditions of the plant. So in the end, you can’t be sure what you and your developing baby are getting with that shake.

Nutritional needs in pregnancy
A varied, healthy diet along with a daily prenatal vitamin recommended by your healthcare provider should give you all the vitamins, minerals and other nutrients that you and your growing baby need during pregnancy. Adding the extra vitamins found in that shake to your diet might result in exceeding the daily recommended amounts for pregnancy. On the flip side, if you are using a nutritional shake as a meal substitute, you might be missing essential nutrients that you and your baby should be getting from food. Always talk to your healthcare provider about the best way to meet your specific nutritional needs during pregnancy.

So, what to do about that container of protein powder sitting in your pantry or those bottles of energy shake taking up space in the fridge? Our advice? Find a new home for them until after you’ve delivered and are no longer breastfeeding. After all, you want to give your pregnancy a “fair shake,” right?

References:
• Natural Products Database, adapted from The Review of Natural Products. Facts & Comparisons (database online]. St. Louis, MO: Wolters Kluwer Health Inc.; 2012.
• U.S. Food and Drug Administration. FDA 101: Dietary Supplements. https://www.fda.gov/Food/DietarySupplements/UsingDietarySupplements
• U.S. Food and Administration. Daily Values for Infants, Children Less Than 4 Years of Age, and Pregnant and Lactating Women. https://www.fda.gov/food/dietary-supplements-guidance-documents-regulatory-information/dietary-supplement-labeling-guide-appendix-c-daily-values-infants-children-less-4-years-age-and