Can you run an ultra-trail race with a baby bump?

On Saturday, Camille Bruyas proved that it is possible. Pregnant for over four months, the athlete finished in 8th place in the 56km Madeira Island Ultra-Trail (MIUT) before pausing her career for the rest of her pregnancy, as reported by L’Equipe. While her performance is impressive, it has sparked a debate: how far can one push sports efforts without danger, whether for the mother or the unborn baby?

“In the first trimester, there are no particular concerns,” reassures Dr. Olivier Morel, a gynecologist-obstetrician in Nancy. The only notable exception is scuba diving “with the risks associated with oxygenation, even if they are rare.” In other words, as long as the belly has not yet protruded – or barely – almost anything is allowed.

The real danger: sedentary lifestyle

Starting from the end of the first trimester, practicing sports requires more caution. The specialist highlights the “risk of falls, impacts, especially in activities like horseback riding or ultra-trail, but also risks of metabolic imbalance or poor oxygenation.” In ultra-trail, for example, poor glycemic regulation can pose a problem. However, there is no universal rule on stopping sports during pregnancy. “It depends on each woman’s training state and the course of her pregnancy,” he explains.

The main message from the doctor? Encouraging physical activity for all pregnant women, not just elite athletes. “For all pregnant women, it is recommended to have regular physical activity. In most sports practices, there are few reasons to limit them,” he says. In his view, the real danger is sedentary lifestyle. “If you’re pregnant, rest” is advice to avoid. “You absolutely must not do that,” he insists.

The benefits of sports during pregnancy are well-documented. Physical activity helps regulate sugar levels better and reduces the risk of gestational diabetes, affecting 10 to 15% of pregnant women. It also reduces other complications such as premature birth or preeclampsia, according to the obstetrician. Pregnancy already requires extra effort from the heart: “up to 20% of additional cardiac output is directed towards the placenta towards the end of pregnancy.” A well-trained woman will feel this less than a sedentary woman who may quickly feel breathless.

“The baby will not be particularly affected”

For intense sports, Dr. Morel remains cautious but realistic. Even outside of pregnancy, an untrained person tackling 56 km would end up in the emergency room. For an experienced ultra-trail runner, it’s different- “Determining when pregnancy will limit her adaptation capabilities is extremely complicated,” says the practitioner.

The main danger of impact sports like running or horseback riding remains the risk of placental detachment and especially falls. For cycling, for example, there is no absolute contraindication, but it’s better to switch to a stationary bike from the 4th-5th month to avoid falling. For the baby, impacts are cushioned by the amniotic fluid and do not affect fetal development. “Apart from extremely violent direct impacts on the uterus, the baby being touched is exceptional,” the doctor emphasizes.

In general, the doctor recommends to less experienced athletes like Camille Bruyas “anything that involves walking, light jogging, swimming”. He also mentions activities like floor gymnastics, squats- Basically, “anything that allows for good physical activity without causing significant impacts.”