Running While Pregnant: What the Science Says

It's a question I've seen pop up dozens of times in running groups: can you keep running while pregnant? For a long time, medical advice was extremely cautious, recommending a drastic slowdown. Today, recommendations have evolved—and that's pretty reassuring. But, of course, every pregnancy is unique.

⚕️ Important Disclaimer: I am not a medical doctor. What I'm sharing here comes from my research and official recommendations. Please consult your doctor or midwife before making any decisions.

What Official Medical Guidelines Say

Based on my research, the American College of Obstetricians and Gynecologists (ACOG, 2020) and France's Haute Autorité de Santé (HAS) agree: for an uncomplicated pregnancy, moderate physical activity is not only permitted but recommended. ACOG advises at least 150 minutes of moderate-intensity aerobic activity per week.

Running isn't contraindicated if you were already a runner beforehand. The key principle is continuity: continuing an activity you already practiced is different from starting a new one during pregnancy.

However, certain situations are absolute contraindications: placenta previa after 26 weeks, preeclampsia, premature rupture of membranes, etc. This highlights the importance of medical supervision.

Documented Benefits According to Studies

Reduced Risk of Gestational Diabetes

Several meta-analyses (including Davenport et al., 2018, involving over 7,000 women) show a 25 to 40% reduction in the risk of gestational diabetes among active women. This is one of the most well-documented benefits.

Mental Well-being Matters

Exercise during pregnancy is associated with a reduction in depressive and anxious symptoms. For many female runners, maintaining their practice—even if reduced—helps provide a stable anchor during a period of significant change.

Other Mentioned Benefits

• Better weight management (without aiming to restrict gain)
• Reduced risk of preeclampsia
• Improved sleep
• Potentially easier postpartum recovery

One caveat, though: women who exercise during pregnancy often have an overall healthier lifestyle, which can somewhat bias the results of observational studies.

Precautions by Trimester

First Trimester (Weeks 1 to 12)

Fatigue and nausea can naturally diminish the desire to run—and that's perfectly normal. Medically, there's no reason to stop if everything is going well. You can maintain an intensity close to your usual, by listening to your body.

The simplest guide: the talk test. If you can speak in complete sentences during your run, you're likely at a good intensity. Monitoring by heart rate is less reliable because blood volume and resting heart rate increase starting in the first few weeks.

Second Trimester (Weeks 13 to 27)

Often the most comfortable trimester. Energy returns, and nausea subsides. However, biomechanical changes begin:

• Your center of gravity shifts forward
• Relaxin hormone loosens ligaments (leading to more joint instability)
• Blood volume increases by 40 to 50%

Many runners naturally reduce their pace and distance. This is the time to listen to your body rather than sticking to a training plan.

Third Trimester (Weeks 28 to 40)

This is where it gets more challenging for many. The extra weight, compressed diaphragm, pelvic discomfort... Some switch to brisk walking or swimming, while others continue running until the final weeks. There's no universal rule.

If pelvic pain, urinary leakage, or a feeling of heaviness appear, consult a physical therapist specializing in pelvic floor health.

Warning Signs: When to Stop Immediately

ACOG lists warning signs that require immediate cessation of activity and medical consultation:

• Vaginal bleeding
• Regular and painful contractions
• Leakage of amniotic fluid
• Disproportionate shortness of breath (even before exertion)
• Dizziness or faintness
• Chest pain
• Severe headaches
• Calf pain or swelling (risk of thrombosis)

There's no debate about these signs—stop, and consult your doctor.

Postpartum: Patience is Key

Returning to running after childbirth is a topic in itself. According to current recommendations (Goom et al., 2019), it's advisable to wait at least 12 weeks before resuming high-impact exercises, allowing time for the pelvic floor and abdominal tissues to recover—even longer after a C-section.

The return should be gradual and ideally guided by a pelvic floor assessment. Social pressure to "get your body back" quickly pushes some women to resume too soon, carrying a risk of prolapse or long-term urinary incontinence.

Every runner's journey is different. Some regain their pre-pregnancy fitness level in a few months, others need a year or more—and both scenarios are perfectly normal.

The Key Message: Every Pregnancy is Different

A woman who ran until 38 weeks in her first pregnancy might need to stop at 20 weeks during her second. Testimonials from elite athletes who run until delivery are not representative—and should not serve as a benchmark.

Running while pregnant is neither a heroic act nor recklessness. It's a personal, case-by-case decision made in consultation with your healthcare provider.