Dr. Ellie has driven home the point that women are not fragile. And this doesn’t change during pregnancy, despite many years of nonsense conventional wisdom that physical exertion can cause a miscarriage or preterm birth. While it is prudent to be cautious while pregnant, you are not suddenly a delicate flower. So, can you run while pregnant? Absolutely. 

 

While exercising during pregnancy is safe and recommended, you should immediately stop exercising and contact a medical professional if you have:

• • Shortness of breath before exercising, dizziness, or chest pain at any time
  • New calf pain or swelling
  • Uterine contractions, leakage of amniotic fluid, or vaginal bleeding]

 

The American College of Obstetrics and Gynecology’s current position statement on exercise during pregnancy highlights that being physically active while pregnant has been correlated with a higher incidence of vaginal delivery and lower incidences of gestational diabetes, high blood pressure, preterm birth, and low birth weight. It may also help prevent postpartum depression and increase memory and cognition in the child (1, 3). Therefore, they recommend that all pregnant folks exercise for at least 150 minutes per week (usually broken down into five 30-minute workouts) at a moderate intensity (breathing heavily, but can still carry on a conversation) (2).

 

Great, so we definitely want to exercise while we’re pregnant! And you’ve decided that you want to run. Here are some ways to do so as safely as possible: 

 

Running while pregnant

 

First, temperature regulation can be difficult while pregnant. Your metabolism is working very hard at making a fetus and heat is a natural byproduct of metabolism. Additionally, the total volume of blood in your system is increasing by 40–50% as early as your first trimester, and definitely by the second trimester. These factors can make it very hard to cool off. Therefore, make sure to stay well-hydrated, wear loose, breathable clothing, and avoid exercising in high heat, especially with excessive humidity. These precautions are especially important during the first trimester while the body is making these changes to the cardiovascular system to adjust to being pregnant, and while the neural tube is forming in the fetus (which is a very temperature-sensitive process) (1, 3). 

 

There is also less resistance in the blood vessels during pregnancy. This means that it is harder for the blood to return to the heart from systemic circulation (1,3). Therefore, it is beneficial to wear compression socks (during the day, but especially with exercise) (3). Look for athletic compression socks with a compression of 15–20mmHG for a (relatively) gentle compression that is great for exercise.

 

How much can you run while you are pregnant?

 

There is no hard and fast limit according to research, though the duration hasn’t been investigated as much. There is evidence that blood sugar usually gets low after 45 minutes of high-intensity exercise; in order to combat this you can make sure you eat before you run and potentially bring a small snack with you. If you are a new runner, make sure to gradually increase your mileage to allow your body to adjust—it is a great idea to work with a coach to plan your mileages.

 

What about the hormone relaxin?

 

Actually, research now shows that higher levels of progesterone and estrogen during pregnancy are correlated with flexible, achy joints, rather than relaxin which was previously blamed. Estrogen encourages production of type 3 collagen, which is more elastic than other types of collagen, and decreases production of the more rigid type 1 collagen (4). This means that the more estrogen there is, the more flexible your joints are (collagen is what makes up the ligaments that provide passive stability for your joints by connecting bone to bone). When not pregnant, there are higher estrogen levels immediately before you ovulate. 

 

More flexibility sounds nice, right? Well, it is certainly helpful when you need your pelvis to expand to let a head and shoulders through. However, it is also part of the reason that at least 60% of pregnant folks will experience low back pain (1) (I think this number is more like 98% realistically), many will experience pelvic pain, and/or other aches like ankle sprains and carpal tunnel syndrome. Another contributor to these symptoms is the natural change in center of gravity and posture as we gain weight in our abdomens. 

 

What are some good exercises for pregnant runners?

 

So what can we do about this? When our ligaments are not providing support, we can use our muscles to help out—the stronger they are, the more support our joints will have, and we’re likely to have less pain. Similarly, training balance can help the body accommodate changes in the center of gravity and decrease the likelihood of low back pain, pelvic pain, and other injuries like ankle sprains. 

My favorite exercises to accomplish these benefits in pregnant runners are squats or sit to stands, heel raises, and single leg deadlifts (unless you’re experiencing pelvic pain, in which case single-leg exercises can exacerbate symptoms). Using these as a warm up for running takes less than 5 minutes. A couple of precautions are a good idea for resistance training in pregnancy:

• Do not lay on your back for more than a couple of minutes after your first trimester
• Avoid isometric exercises (holding still in an exertional posture, such as plank or wall sit)
  • You can just make these dynamic by adding an arm or leg movement, this will help the body regulate blood pressure
• Do not perform a valsalva maneuver (exhaling against a closed glottis, often done during weightlifting) as it has been shown to avert blood flow from the fetus

 

There are some folks who say that you need to contract your pelvic floor (Kegel) while running. This is absolutely unnecessary and in fact can cause tension that will be obstructive if you are trying to deliver vaginally. If you are not having symptoms of leaking urine, your pelvic floor is already doing its job while you are running. If you are leaking urine or having pelvic pain while running, you should see a professional for a more personalized, realistic program to relieve your symptoms rather than making your run super stressful by gripping your vagina the whole time.

 

If you do find that you are experiencing lower back pain, pelvic pain, leaking of urine, or any other aches or discomforts with exercise, it is important to see a physical therapist who has experience with, and knowledge of, pregnancy and exercise. This is a subspecialty of physical therapy, and those of us who work in this area have done extensive continuing education.

 

Is running right for your pregnancy?

 

Lastly, it is important to give yourself grace during pregnancy, and do what feels right to you. We are naturally more tired while pregnant, primarily because we’re making a person, but also because our movements become less efficient as we accommodate our growing abdomens. Therefore, there’s a lot more stress on the cardiovascular system as it pumps more blood to supply the fetus with oxygen and nutrients, and in the later second and third trimesters our lungs have less space to expand to take in oxygen. I am a fitness professional, and I could barely make myself ride a stationary bike during my first trimester! (It got better during the second.)

 

So, YES, running is safe during pregnancy. You stand to gain so many benefits for yourself and your fetus by exercising, and you are most likely to continue exercising if you do something that you love. So keep (or start) running your heart out!

 

Yes, running is safe during pregnancy – Dr. Helene Darmanin, Physical Therapist, owner of Mama Bear PT

 

1. Birsner ML, Gyamfi-Bannerman C. Physical Activity and Exercise During Pregnancy and the Postpartum Period. ACOG. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2020/04/physical-activity-and-exercise-during-pregnancy-and-the-postpartum-period. Published March 4, 2020. Accessed March 10, 2021. 
2. U.S. Department of Health and Human Services. Physical activity guidelines for Americans . 2nd ed. Washington, DC: DHHS; 2018. Available at: https://health.gov/paguidelines/second-edition/. Retrieved October 18, 2019.
3. Harrast MA, Bowersock A, Lin CY. Caring for and Counseling the Peripartum Runner. In: Clinical Care of the Runner: Assessment, Biomechanical Principles, and Injury Management. Philadelphia, PA: Elsevier; 2020:259-269. 
4. Krapf J. Pregnancy, Hormones, and the Pelvic Floor. lecture presented at the: myPFM Webinar; January 2021.