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How does pregnancy affect your marathon time?

What the experience of pro runners before and after pregnancy can tell us about its effects on performance

steph bruce marathon project Photo by: Chris Lotsbom

For years, becoming pregnant was a career killer for a professional female athlete. Things have begun to improve since runners like Allyson Felix, Alysia Montaño and Kara Goucher (along with many high-profile athletes in other sports) have spoken out, and many marathoners, including Americans Gwen Jorgensen and Steph Bruce and Canadians Hilary Stellingwerff and Malindi Elmore have experienced great success in running both before and after having children, how does pregnancy actually affect post-partum performance? A recent study published in the European Journal of Sport Science says giving birth has little to no impact on a woman’s athletic capabilities.

The study

This, of course, will likely not be a surprise to many women. Aside from examples like Paula Radcliffe, who won the New York Marathon less than a year after the birth of her daughter, or Allyson Felix, who has continued to win Olympic medals even after having a child in 2018, thousands of recreational female runners have continued to clock personal bests after pregnancy.

allyson felix
Allyson Felix with her daughter at the USA Olympic Track and Field Team Trials in 2021. Photo: Kevin Morris

So while the results of this study aren’t earth-shattering, the researchers have provided some data to back up what most women (and many men) already know. They analyzed the careers of 150 of the fastest female marathoners of all time, based on historical records maintained by World Athletics. Of these women, they found 37 who gave birth during their careers (23 had one child, 14 had two). 

The results

Their data showed that 26 of the 37 women ran their personal best time in the marathon (2:21 on average) after the birth of their first child. To break it down further, of the 23 women who had one child during their career, 15 ran their best time after giving birth. In the two-child group, five ran their best time between kids and six ran their best time after their second child was born.

2023 Ottawa Marathon Malindi Elmore
Malindi Elmore, mom to two young boys, set the Canadian marathon record in Houston in 2020. Photo: Victah Sailer

From these stats, you might start to think that pregnancy has a generally positive impact on performance, but there are other factors here to consider, the main one being the age of the athlete. According to the research, the amount of time off ranged widely between runners. Some took as little as nine months away from competitive sport, others 94 months (nearly eight years). The average time away was about 23 months, which, depending on how old the athlete was when she became pregnant, could have an effect on performance. 

Stephanie Bruce on running while pregnant: “It doesn’t have to make sense to everyone”

The researchers thought of this too. They compared the career trajectory of the women with their age and found that most peaked at around 31 or 32 (31.7, to be exact). Women who gave birth and returned to competition before hitting this age tended to run faster after pregnancy, and those who did so after tended to slow down. In other words, it wasn’t the pregnancy that affected their performance, it was their age (note: there are still many women who continue to get faster after 32; this was just the general trend in the data).

What does this mean for recreational runners?

This proves that female runners everywhere, including those who aren’t elite, can still have successful, fulfilling running careers after having children. The important thing to remember here is that returning to running successfully after pregnancy hinges on patience and careful planning. 

paula radcliffe
Former marathon world record holder Paula Radcliffe. Photo: Sport Evolution

We don’t need to tell you that pregnancy and childbirth are very stressful for the body, and it’s important to take time to rest and recover–possibly more time than you expect. While pregnancy and childbirth are not injuries, when you’re ready to return to running, it makes sense to build up your mileage slowly and carefully.

By being thoughtful and patient about how to safely return to running, women everywhere can continue to participate in their favourite sport for years after having children (and inspire their little ones in the process).

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