Can You Run a Marathon While Pregnant?

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The answer is a resounding "yes." You can run a marathon while pregnant if you're an experienced marathoner who has received clearance from your doctor. Safety is paramount, and it's essential to keep your heart rate below 90% of your maximum during your runs.

In recent years, there have been significant advancements in our understanding of safe exercise for pregnant women. It wasn't too long ago when the prevailing belief was that running while pregnant could potentially harm the baby or even lead to a miscarriage. The notion of running a marathon during pregnancy was often met with skepticism.

Can you run a marathon pregnant?

It's important to dispel these myths and acknowledge the reality that running a marathon while pregnant is indeed possible. I have coached numerous pregnant marathoners and have had friends who completed marathons during pregnancy.

Despite the feasibility, many pregnant women still grapple with fears and reservations. The primary goal of this article is to address these concerns with evidence-based facts. Embarking on the journey of running a marathon while pregnant can deepen your appreciation for your body's capabilities and transform you into a more attuned runner.

Running a Marathon While Pregnant: What You Need to Know

The available evidence does not suggest that running long distances during pregnancy can jeopardize your baby's well-being or your own health, as long as you avoid sustaining an elevated heart rate for extended periods.

In fact, research indicates that exercise during pregnancy can offer numerous health benefits for both mothers and babies. A 2011 study, for instance, highlighted improvements in fetal development, including heightened attentiveness, increased lean muscle mass, enhanced discipline, and heightened neurodevelopment.

Guidelines for Running a Marathon While Pregnant

Who Can Run a Marathon While Pregnant?

Pregnant women can safely train for a marathon if they:

  • Have recently completed a marathon
  • Were accustomed to marathon training before becoming pregnant
  • Have received clearance from their OB/GYN
  • Do not have complications or a high-risk pregnancy
  • Run the marathon for enjoyment rather than a time goal
  • Maintain their heart rate below 90% of their maximum
  • Focus on pelvic floor, glute, hip, and core exercises
  • Listen to their bodies and are willing to adjust goals
  • Prioritize proper nutrition and hydration

Who Shouldn't Run a Marathon While Pregnant?

Pregnant women should refrain from training for a marathon if they:

  • Have not run a marathon previously or lack a solid training base
  • Lack medical clearance
  • Experience complications or have a high-risk pregnancy, including conditions like preeclampsia or placenta previa
  • Refuse to adapt their goals based on their body's needs
  • Ignore pain or restrict their food intake to avoid weight gain
  • Neglect physical therapy and pelvic floor exercises
  • Pursue a marathon personal record with rigidity

Signs to Stop Running While Pregnant

Pregnant women should cease running or reduce their activity levels if they experience symptoms such as vaginal bleeding, bladder leakage, dizziness, painful contractions, pressure or pelvic pain, difficulty recovering between runs, round ligament pain, or various types of pain and low energy.

Research Findings on Training for a Marathon While Pregnant

  • Running does not significantly affect the baby's heart rate if the mother's heart rate is maintained below 90% of her maximum.
  • Elite athletes have trained during pregnancy without adverse effects on their health or their baby's health.
  • The risk of overheating while running is highest in the first trimester but is low; it's advisable to avoid running in hot weather conditions.
  • Running long distances or at a higher intensity minimally affects the baby's blood supply via the umbilical cord, thanks to the body's natural protective mechanisms.
  • Pregnant women need increased water intake to support greater blood supply and amniotic fluid, so staying properly hydrated is crucial.
  • As pregnancy progresses, gait changes occur, including an anterior pelvic tilt, wider stance, and longer ground contact. These changes can be mitigated through core, hip, and glute strengthening exercises.

Myth versus reality: The most common myths about running while pregnant

Training Tips for Running a Marathon While Pregnant

  • Prioritize running by feel rather than specific time goals.
  • Emphasize building a strong training base with more easy miles.
  • Consider incorporating hill workouts for improved overall running economy.
  • Allow for increased recovery time between runs and workouts.
  • Modify intensity and volume to suit your body's needs.

Tips for Safe Marathon Training During Pregnancy

  1. Monitor Heart Rate: Running doesn't adversely affect your baby's heart rate as long as your own heart rate remains below 90% of your maximum.
  2. Elite Athlete Inspiration: Elite athletes have successfully trained and had healthy pregnancies, demonstrating that it's possible to maintain an active lifestyle.
  3. Avoid Overheating: Be cautious about overheating, especially during the first trimester. Steer clear of running in hot weather conditions.
  4. Umbilical Cord and Fetal Protection: Running long distances or at higher intensities minimally affects the baby's blood supply through the umbilical cord. Your body naturally safeguards the fetus.
  5. Stay Hydrated: Pregnancy increases your need for water to support greater blood supply and amniotic fluid. Ensure you stay hydrated and avoid feeling thirsty.
  6. Gait Changes: Expect changes in your gait as your pregnancy progresses, including an anterior pelvic tilt, wider stance, and longer ground contact. Strengthen your core, hips, and glutes to counteract these changes. Consider using a program like ReCORE for prenatal runners.
  7. No Evidence of Harm: There is no evidence to suggest that training for a marathon during pregnancy leads to preterm labor, miscarriage, or low birth weight.
  8. Pelvic Floor Strengthening: Running while pregnant can potentially weaken your pelvic floor. However, this can be mitigated by incorporating strength exercises and using a maternity support belt.
  9. Training by RPE: When training for a marathon during pregnancy, focus on Rate of Perceived Exertion (RPE). Pay attention to how your body feels rather than specific pace or time goals.
  10. Adjusting Training Phases: Recognize that training for a marathon while pregnant will differ from non-pregnant training, particularly if you're an experienced runner. Follow these guidelines for safer training:
    • Listen to your body; if you feel exhausted during a run, don't push too hard.
    • Embrace a base phase with a focus on endurance over speed.
    • Consider incorporating hill workouts for an improved running economy.
    • Allow for increased recovery time between long runs and workouts.
    • Adjust intensity and volume to match your body's needs.
  11. Scale Effort and Volume: Modify the intensity and volume of your workouts to align with your body's capabilities. For example, conduct tempo runs at marathon effort rather than threshold effort. Ensure longer recovery intervals between sessions.
  12. Weather Considerations: Avoid running in extreme weather conditions, especially when it's too hot or slippery. Be a fair-weather runner or opt for indoor treadmill workouts when necessary.
  13. Heart Rate Monitoring: Keep your heart rate below 90% of your maximum heart rate. You can train based on the Rate of Perceived Exertion (RPE) or heart rate rather than a specific pace. RPE considers factors like heart rate, breath, sweat rate, fatigue, and overall feel.
  14. Nutrition and Hydration: As your pregnancy progresses, you'll need additional calories and hydration with electrolytes. Aim for approximately 300 extra calories in the second trimester and 450 to 500 in the third. Ensure your urine remains pale in color to indicate proper hydration.
  15. Maternity Support Belt: As your belly grows, your pelvic area, bladder, and back will require more support. Consider using a maternity support belt, such as ReCore’s FITSplint. If your feet have grown (a common occurrence during pregnancy), get fitted for new running shoes.
  16. Consult a Pelvic Floor Physical Therapist: Seek the guidance of a Pelvic Floor Physical Therapist (PFPT) early in your pregnancy to strengthen your pelvic floor and core. Consistently perform the exercises they recommend, which will help with your postpartum running journey.

Running a Marathon in Each Trimester

  • First Trimester: Running a marathon is possible, especially if you don't experience morning sickness or low energy. Avoid pushing for personal best times and stay clear of high-heat conditions.
  • Second Trimester: You can still run a marathon in your second trimester. However, be mindful not to exceed your upper limits of effort or heart rate. Consider using an exercise belly band for added support.
  • Third Trimester: Running a marathon during the third trimester is feasible. Expect your pace to be slower than your non-pregnant performance. Focus on completing the distance and feeling good rather than achieving specific time goals. Continue with core and pelvic floor exercises to stay strong.
Why you can trust Sabrina Wieser
Runningbrina is committed to bringing you unbiased ratings and information. Her editorial content is not influenced by advertisers. Sabrina uses data-driven methodologies to evaluate all products, so all brands are measured equally.
  • Most featured running blog, past 6 years
  • USATF certified running coach
  • Experienced endurance athlete
  • 7 marathons

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