Groundbreaking New Study on Pregnancy and Athletic Performance

On the morning of August 27, Allison Baca was greeted by a foreboding gloom at the trailhead beneath 13,229-foot Mount Audubon, in Colorado. She decided to give her objective a shot anyway, planning to turn around if the weather went from gloom to doom. 

With her partner Tony, she had blocked off this date on the calendar weeks in advance as her chance to spend all morning in the mountains, chasing history on the iconic Pawnee-Buchanan Loop above Boulder. Those free mornings were extra special. Free time has been much harder to find on the calendar since she became a mom last year.

On March 26, 2021, she gave birth to her first child, Mateo. The 17 months since then have been a journey, full of ups and downs that only a parent can truly understand (as a soon-to-be first-time dad, I have watched enough preparing-for-baby videos to understand that I won’t understand the chaos until I live it). 

Something about that journey made Allison even more unstoppable on the trails. So she went into the mountains with confidence . . . and also some time constraints. 

Pawnee-Buchanan is a 27-mile route with 7,000 feet of climbing over technical mountain terrain. Ever since Anton Krupicka first reset what was possible in 2010 by running 4:50, Boulder trail runners have taken their cracks at the route, with plenty of cracked ankles and broken spirits to show for it. The women’s record stood at 5:34, set by stellar athlete Emily Caldwell. Challenging that time would require speed and technical proficiency. But most of all, it would require strength. Luckily, over the previous 17 months, Allison had honed a new skill that she’d be taking with her: Mom Strength.

Over the 27 miles, she fought through vicious wind gusts in remote wilderness, with enough ups and downs to ruin any quad muscle. Her final time? An astounding 5 hours and 5 minutes. Allison beat her goals and made history. “It was exciting to finish the loop and realize that I was able to run faster than I had ever imagined starting the day!” she said.

RELATED: How Pregnancy Affects Your Marathon Time

When asked about how pregnancy and motherhood changed her as an athlete leading up to the performance, she paused. In that pause, I sensed a weight that someone can only feel when they have lived through the shit, for better and for worse, and are trying to summarize something messy into something neat.

“Motherhood has given me more of an identity outside of running,” Allison said. “Sports used to be my identity, and they still are a part of my identity, but they are not everything. If a run doesn’t go well, I used to dwell on it. Now there isn’t time to dwell–I need to bring my best mom-self through the front door after good or bad runs. My life feels more well-rounded, and it can be exhausting. But I think it helps my running.”

The journey was full of that uncertain chaos, and very few parenting journeys are as tidy as they can seem from the outside. For Allison, it all led to a mind-blowing FKT performance, and I think there’s a strong argument that it’s one of the best “FKTs of the Year” in the whole world. We can’t be sure what propelled her to such a historic performance–it’s some combination of talent, toughness, training, and intangibles. 

But based on a study that was just released, I think we can draw one certain conclusion about at least one of those intangibles. For some athletes, Mom Strength can be a superpower… even when it comes with some mom exhaustion. 

Study Overview: The Impact of Pregnancy in Elite Runners

The study was published online ahead of print in August 2022 in the Medicine & Science in Sports & Exercise Journal, reviewing training and performance trajectories of 42 elite runners during and after pregnancy. The author list was a who’s who of top researchers: Francine Darroch, Amy Schneeberg, Ryan Brodie, Zachary Ferraro, Dylan Wykes, Sarita Hira, Audrey Giles, Kristi Adamo, and Trent Stellingwerff. The superstar team tackled a big, thorny topic that is usually full of whispers and innuendo, rather than data. 

Leaving the world of anecdotes and wishful thinking behind, what does pregnancy actually do to athletes?

Let’s get straight to the fascinating finding: athletes “who intended to return to high-level competition did so at a statistically similar level of performance in the 1 to 3-year period post-pregnancy.” But there’s something even more exciting. A whopping 46% of these elite athletes improved performances post-pregnancy. 

A baby does not mean an athlete has to press stop and rewind. Those little poop machines sometimes just require a brief slow-down, followed by fast-forwarding to the best part of the show. It’s complicated, though, and everyone is different. 

In interpreting the study, I’ll try to highlight just how different it shows that every journey can be, even if those complications might not make the headlines.

Study Context

The study was such a massive leap into the unknown because it was the first of its kind. As the authors said, “we are unaware of any previous study with significant participant numbers that has systematically and statistically investigated directly published quantitative performance outcomes before and after pregnancy.” 

A 2019 study in BMJ Open Sport and Exercise Medicine had completed a pregnancy questionnaire and interview with 34 elite athletes and compared that to a control group, finding no differences in pregnancy outcomes or returns to full activity. That study didn’t look at long-term training or performance levels, so the 2022 study is really talking about venturing into a new research frontier.

To explore that frontier, the research team set some constraints. They would be gathering data on an athlete’s first pregnancy only. In addition, the participants would be elite athletes, with times equivalent to a 2:46 marathon or faster in events 1,500 meters and up. The participants received a 139-question survey on training during and after pregnancy, completed with data from their training logs. 35 of the 42 athletes had performance times from the 1 to 3 years before birth on the World Athletics website, and those times were compared with postpartum results.

What a cool study design! By focusing on elite athletes, the researchers set up a tough hurdle to jump. Participants had already been striving to optimize their performances, so how does pregnancy affect optimization? It seems suboptimal to have a body’s processes taken over by an ever-growing parasite for 10 months, right? Wrong, of course. The study results demonstrated the complexities of long-term performance, since many of the athletes actually got faster than before.

Study Findings

First, 57% of athletes reported conceiving during a period of decreased training load, with 24% intentionally decreasing training around conception. That may show that some athletes think that elite training is less conducive to conception, or that athletes focus on family planning during a break from competition.

Second, during pregnancy, athletes decreased training load from pre-pregnancy levels. They ran significantly fewer sessions, dropping from 9 per week to 5 per week, and the proportion of intensity decreased. Running volume decreased to 64-73% of pre-pregnancy in the first trimester, 49-54% in the second trimester, and 29-36% in third trimester, with more cross training toward the end of pregnancy than the beginning. Running paces slowed significantly, up to 23% in the third trimester. But athletes still averaged significantly more training than recommended by international exercise guidelines for pregnant people.

Third, after pregnancy, participants averaged 6 weeks off running and 3 weeks off cross training. They returned to 80% of pre-pregnancy loads at 14 weeks postpartum. The error bars on those numbers were large, showing substantial inter-individual variability. 

After pregnancy, athletes raced less, dropping from 7.2 races per year to 2.8 races per year in the year after pregnancy, increasing to 4.4 races per year in the 3 to 5 years postpartum. But what’s so exciting is what they did with those races.

Performance Findings

60% of the participants planned to return to pre-pregnancy levels or greater. This cohort saw no change in performance levels. Most exciting of all, “Nearly half of the athletes (46%) had better IAAF performance scores in the 1- to-2 years post-pregnancy than during the two years before birth.” 

While those numbers are exciting and hopeful, they are a bit more complex than they might seem at first glance. What about the 54% of athletes who didn’t improve in the 2 years after pregnancy, despite intending to? What about the stories that aren’t leading off running articles like this one? That’s where the discussion gets a bit more complicated.

Pregnancy and Performance

In the discussions around pregnancy and training, I think we often seek simple narratives. I’m looking squarely in the mirror when I say that. 

To start this article, I framed pregnancy as a potential superpower, which it clearly is not for everyone. While there are examples of athletes coming back stronger than ever, like Allison, there are many stories of athletes that really struggle to train during and after pregnancy. Some of those athletes never reach the same levels again, and those stories need to be told too.

As the authors say, “the limited data do not appear to support pregnancy as ergogenic for any physiological variables.” Thus, the process of pregnancy alone is unlikely to be a performance enhancer. But as the study found, it can coincide with improvements in performance in many athletes, even elite athletes that were already pushing their training limits. 

Headline: WOW, that is so exciting and hopeful!

Subheading: HOWEVER, it’s often so scary and uncertain.

The hopeful data need to be understood in conjunction with the negative outcomes, too. I have been fortunate to coach many athletes through and beyond pregnancy, including Allison. I was excited to tell Allison’s story because she is, well, a badass, and it can be motivating to have these uplifting models of Mom Strength. This study showed that intention to return at higher levels than before pregnancy was a key element in actually returning and exceeding to those levels, so I want to support a system of all-caps BELIEF that lets an athlete know it’s possible.

But it won’t happen for everyone. If 46% of athletes had better performance scores in the 2 years post-pregnancy than 2 years pre-birth, that means 54% did not. Those 54% may go much faster at Year-3 or Year-5 or Year-10, and I imagine each of those data points on both sides of the improvement curve involve stories of joy and sadness that are rarely told publicly. 

This study showed that intention to return at higher levels than before pregnancy was a key element in actually returning and exceeding to those levels, so I want to support a system of all-caps BELIEF that lets an athlete know it’s possible.

The authors highlight the complexity and those stories. “Our results may reflect a shift in the broader athletics culture and wider acceptance that individuals continue to compete at an elite level, and some possibly at a higher level than they did pre-pregnancy.” 

RELATED: The Truth About Pregnancy’s Effects on Running and Body Image

“Taken together, these findings indicate that childbirth can be a positive part of an elite athlete’s career; the forced break may have both mental and physical benefits. Additionally, our own previous research has shown that a focus on motherhood and shifting priorities may alleviate some of the stress placed on performance outcomes particularly when athletes have strong social support and childcare.”

Included in those few sentences are likely thousands of stories that the researchers know about, but aren’t fit to print in an academic journal. Allison’s journey has been scary and non-linear at times, and her specific stories are not mine to tell. The same goes for most journeys during and beyond pregnancy.

Some athletes get faster. Some get slower. Some love the evolving process of balancing motherhood and athletics. Some cry themselves to sleep from the weight of it all. Some bodies and brains thrive, others live through tough times that only a few loved ones might ever know about. Most mix all of those feelings and fears together at one time or another.

The Uncertainty of Pregnancy, Running, and Comebacks

All of those stories are equally valid. I wrote this article now because my wife/co-coach Megan is 30 weeks pregnant with our first child. She’s one of the best athletes in the world, with 5 national championships and dozens of course records that boggle the mind. But a couple months before conception, she felt chest pain that turned out to be a heart condition. She has barely exercised during pregnancy, her 20-mile runs replaced by daily trips to the creek where we read books and nature bathe. It has been a simultaneously beautiful and scary process so far, and I imagine that’s not going to stop anytime soon.

An athlete like Megan doesn’t neatly fit into this study. Yes, she’s elite. But she hasn’t been able to train through pregnancy. Yes, she hasn’t gotten injured. But it’s tough to get injured when reading at the creek, outside of papercuts. And yes, she intends to come back stronger and faster than ever. But it’s not a choice.

If anyone can do it, though, it’s Megan. This study adds a few cups to the hope bucket, for her and other athletes going through the pregnancy process. That is so exciting! And it still doesn’t change the fact that many of the stories around pregnancy won’t be as neat and simple as the caption of this article implies.

I know one thing for sure: Megan is the strongest person I have ever met. Whether she runs faster in the future or not, well, that’s out of her control, though I think she and other athletes can be full of realistic, pragmatic hope. 

Either way, I am popping some popcorn for the show ahead. Megan is so damn strong. Now just imagine what she can accomplish in life with Mom Strength.

David Roche partners with runners of all abilities through his coaching service, Some Work, All Play. With Megan Roche, M.D., he hosts the Some Work, All Play podcast on running (and other things), and they answer training questions in a bonus podcast and newsletter on their Patreon page starting at $5 a month.