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

Do you enjoy protein shakes, adding protein powder to your smoothies, or using pre-workout mixes with protein? My friend, Emily, is currently in her first trimester and loves getting extra protein. Before she got pregnant, she started power lifting, which also came with extra protein supplementation. Once she got pregnant, Emily asked me, like so many others in her position, if she could continue her protein supplementation during pregnancy and when breastfeeding.

With any pregnancy, there is a 3% chance of developing a birth defect.  So I looked into protein supplementation to see if it changes the risk for birth defects, side effects during breastfeeding, or any other issues. That way, Emily could make a well-informed decision for her health and the health of her family.

Many of these protein products contain types of protein that are also found in everyday foods and even in breast milk. Everyone needs a certain amount of protein every day as a part of a balanced diet. However, there are certain reasons why someone might have a specific daily protein intake goal. Like Emily, many people are interested in having more protein to build muscle. There are other health conditions, like phenylketonuria (PKU), that affect how much protein you should get in your diet. Ultimately, it is very important for you to review your personal daily protein intake goals with your healthcare team to make sure your health is supported.

Not every protein supplement has been well studied, so information on using them during pregnancy or breastfeeding is limited. In addition, many protein powders and drinks also include other ingredients, such as added vitamins or herbal products. For more information on herbal products, check out our fact sheet on here:  https://mothertobaby.org/fact-sheets/herbal-products-pregnancy/.

Supplements are regulated differently than prescription drugs. Even though the United States Food and Drug Administration (FDA) regulates supplements, the FDA doesn’t check every product for safety or effectiveness before it goes on the shelf. This means some protein powders might contain some unknown or unlisted ingredients.

So before adding that extra scoop of protein powder, take some time to figure out if protein supplementation is right for you.

How Much Protein Do You Need?

How much protein you need depends on different factors, such as age, activity level, and health. Some proteins have a daily recommended dietary allowance (RDA). The RDA depends on a person’s weight. You, most likely, get some amount of protein from your diet naturally. It’s important to take your diet into consideration when trying to figure out how much protein you should be having. Because there are so many things to consider, it’s recommended to talk with your healthcare team to make sure you are meeting your nutritional needs. Getting the right amount of protein for you is not expected to increase the risk for issues during pregnancy or side effects during breastfeeding.

What are the typical amino acids in protein supplements?

Most protein powders contain many amino acids. Amino acids are the building blocks of protein. The list below may not include everything that might be found in your protein powder. Since not every amino acid has an RDA, here is a list of the known amino acids with an RDA. It’s always a good idea to double check with your healthcare team on what your specific protein intake goals are.

• Cysteine & Methionine*
  • RDA during pregnancy: 25 mg/kg

  • RDA during breastfeeding: 26 mg/kg

• Isoleucine
  • RDA during pregnancy: 25 mg/kg

  • RDA during breastfeeding: 30 mg/kg

• Leucine
  • RDA during pregnancy: 56 mg/kg

  • RDA during breastfeeding: 62 mg/kg

• Lysine

  • RDA for adults: 12 mg/kg

• Threonine
  • RDA during pregnancy: 26 mg/kg

  • RDA during breastfeeding: 30 mg/kg

• Tryptophan

  • RDA for adults: 3.5 mg/kg

• Valine
  • RDA for pregnancy: 31 mg/kg

  • RDA for breastfeeding: 35 mg/kg

*Note: The RDA for methionine and cysteine is combined.

What About Other Ingredients?

Often, protein powders can have other ingredients in addition to the protein. Again, check the label on your specific products, as they can vary.

• Caffeine: For more information on caffeine, check out our fact sheet: https://mothertobaby.org/fact-sheets/caffeine-pregnancy/
• Collagen: There aren’t any studies that look at the use of collagen as a supplement during human pregnancy or breastfeeding.
• Creatine: Creatine is naturally found in the body and in breastmilk. There aren’t any studies that look at the use of creatine as a supplement during human pregnancy or breastfeeding.

So What Now?

Emily realized that since there is not a lot of information on protein supplementation during pregnancy and breastfeeding. The best next step for her was to chat with her healthcare team about what would best support her health and pregnancy. Some providers on her healthcare team include her primary care provider, her nurse-midwife, her nutritionist, and her endocrine specialist. Emily decided that she’s even going to talk to a lactation consultant now so she can have time to prepare for breastfeeding. She knew how to measure how much protein she was getting in her protein powder, but she needed help estimating how much protein she naturally gets in her diet as well.

Have more questions about supplements or other exposures during pregnancy or breastfeeding? Talk to a teratogen-information specialist at MotherToBaby.org.

References

Elango R. & O Ball, R. 2016. Protein and amino acid requirements during pregnancy. Advances in Nutrition, 7(4): 839-844. https://doi.org/10.3945/an.115.011817.

Food and Nutrition Board. 2005. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. Washington, DC: The National Academies Press.

National Research Council. 1989. Recommended dietary allowances: 10th Edition. Washington, DC: The National Academies Press. https://doi.org/10.17226/1349.

U.S. Food & Drug Administration. 2025. Infant formula. https://www.fda.gov/food/resources-you-food/infant-formula