A Conversation with Dr. Margie Davenport About How New Research is Challenging Old Beliefs
It’s big news and great news for the growing group of women who recognize the health benefits of lifting heavier and have made it part of their exercise regimes. And, it’s only the beginning, confirms the senior author of the study, Margie Davenport, and director of the Program for Pregnancy and Postpartum Health at the University of Alberta.
Tasked with developing Canada’s 2019 guideline of physical activity during pregnancy, Davenport found compelling evidence that physical activity in pregnancy was not only safe but beneficial for the mother and baby. However, when it came to weight-lifting, Davenport noticed that there were only expert opinions, no high-quality studies. 
Davenport and her team at the University of Alberta studied 20 women, 10 who were pregnant and 10 who weren’t. All 20 performed three exercises – a barbell back squat, bench press and deadlift – at increasing intensities up to 70-75% of their max effort. The study concluded that high-intensity resistance exercises were well tolerated by the mother and fetus.
To learn more about the study and its impact, we spoke with Dr. Margie Davenport about what drove the research, what it means now, and what comes next.
Margie Davenport is director of the Program for Pregnancy and Postpartum Health at the University of Alberta and very recent recipient of the prestigious Drinkwater Leadership Award in Women’s Health, Sport & Physical Activity award for her work in the field, and senior author of a study that confirms safety of high-intensity resistance training during pregnancy.
WHCC: What inspired the study to start with?
Margie Davenport: I led the development of the 2019 Canadian guidelines on physical activities throughout pregnancy, and as part of that guidance, we actually synthesized all available literature, which was then distilled into 12 systematic reviews and meta-analyses. Based on that work, we found very compelling and extensive evidence demonstrating that being physically active during pregnancy is not only safe, but it’s actually quite beneficial as well for the health of both the mother and the baby. We saw that there was about a 40% reduction in the odds of developing pregnancy complications, including gestational diabetes, pre-eclampsia, and gestational hypertension. We also, importantly, found that it was not associated with an increased risk of having a miscarriage, having an early baby, or a small baby. These were really important questions that needed to be answered to alleviate key concerns that women have about exercise and pregnancy. Now, when we did the systematic reviews, we were, maybe not that surprised, but certainly disappointed that we weren’t able to talk a lot about the more intense or vigorous intensity activity.
Historically, what happens when we talk about weight lifting and pregnancy most people are told to do moderate intensity, but we know that there’s a subset of the population, especially a growing population of women who are lifting heavy, they’re doing cross-fit or powerlifting before they were pregnant, and then they want to start a family, they become pregnant, and they just don’t know what to do. So, about two years after the guideline came out, we did an online survey where we recruited participants who were lifting greater than 80% of their 1RM (repetitions max). When we synthesized that information, what we actually found was that there was a 51% reduction in the odds of developing adverse pregnancy outcomes if they continued to lift heavy throughout their pregnancy, compared to what most guidelines will say, which is to reduce activity level or lifting levels to a more moderate range.
Based on those extensive health benefits, the obvious next question is, (a survey gives you a certain amount of information) but is it actually safe to be lifting these heavy weights while you’re pregnant? That’s what inspired the study we’re talking about today, where we recruited pregnant women who had been lifting before and during their pregnancy, and we looked at the fetal responses to that activity.
WHCC: So getting to this study was quite a long journey?
MD: Absolutely. We’re in 2025. We wrapped up the systematic reviews in 2018. We’re talking about a six to seven-year process to be able to get to the point where we’re doing these higher-level studies. And we still have a long way to go, to truly understand the impact of heavy lifting during pregnancy. But it’s a really really important question. I’m an older mom myself. I was in my mid-to-late 30s when I became pregnant. I’m certainly concerned about my overall bone health as we get older. Our bone mineral density is going to drop. Our muscle mass is also going to drop. And one of the essential ways that we can support our overall muscle and bone health is to lift heavy weights as we get older. So if we’re telling women to stop lifting during pregnancy, or at least reduce the intensity of the lifting that they were doing, we need to have strong information to support that. But, we didn’t.
WHCC: How have the reactions been to the study?
MD: I would say excitement because for people who already are lifting heavy before they were pregnant, and have seen the benefits – the stress relief, the maintenance of muscle mass, bone health overall – they want to continue while they’re pregnant. And there’s a lot of stigma, a lot of concern about the safety and potential benefits or harms of lifting heavy during pregnancy. So I think in some ways, the greatest response is a bit of relief that this is something that can be continued at least within the scope of the current study. But I think there’s also a desire now to have a lot more information to better understand if there are limits in terms of how heavy the can be lifting, if there are certain types of activities we should be doing in terms of different types of lifts, whether it’s Olympic lifts, or just more traditional bicep curls. So I think the appetite for more information has certainly grown.
WHCC: There’s a real rise in women lifting weights, isn’t there?
MD: Absolutely, I think it’s a really important, great change that’s happening because of all the extensive health benefits. For the general population, but certainly in pregnancy as well, we are underestimating the power of lifting weights during pregnancy. We’re just barely scratching the surface. So it’s an exciting time for the field for sure.
WHCC: Can you share what comes next?
MD: The next step is that we need to do heavier lifting. In this particular study, the maximal weight lift that we had was 90% of their 10RM (repetitions max). That’s about equivalent to maybe 70 to 75% of maximal effort, much heavier than we have ever seen in the literature. But we still do need to do heavier lifts for those people who are used to lifting quite heavy, our athletic populations. We’re seeing this incredible rise in female athletes who are starting families mid-career, and we do want to support them because they do want to continue to lift heavy while they’re pregnant. So certainly having heavier weight lifted in future studies, but also doing more longitudinal studies, which means that instead of having women come in for one single session, follow them during their pregnancy to see if continued engagement in resistance training during pregnancy, if you start before pregnancy, you continue to the first and second trimester, is there a point where you should consider stopping? Or is it actually just fine to lift until the day that you deliver?
WHCC: What do the findings mean for athletes and for the average woman who’s already working out?
MD: When we talk about the general population, whether they’re less active individuals or they’re recreational athletes, this provides a bit of reassurance and security. Most people are not pushing the limits of what they can lift during pregnancy, but we’re not restricted to this idea that you can only lift a moderate intensity of weight while you’re pregnant. So if you go above it or you desire to go above it, that seems to be okay up until this particular threshold. For our elite athletes, who want to lift quite heavy, unfortunately, the traditional sort of recommendation is that as pregnancy progresses, everybody should reduce their activity levels. However, that’s not based on anything except just sort of general recommendations, and that’s okay if you choose to reduce your activity levels or you’re not feeling well enough to continue activity during pregnancy. However, there are a number of women who feel great while they’re pregnant, and they do want to continue to train. This data is designed to help support them. We have a long way to go to really answer those particular questions, but it’s an important first step for those individuals who do wish to continue to lift heavier weights while they’re pregnant.
WHCC: How do cardio and HIIT come into the findings?
MD: HIIT. We looked at that first. Before we ever did the heavy lifting question, the first thing we tried to tackle was this idea of HIIT training. Similarly, we’ve been seeing this increased interest in doing HIIT training before pregnancy. If you like to have nice short sessions where you can push yourself pretty hard before you’re pregnant, many women want to do it during pregnancy. We did this study right in the middle of COVID, and it was probably the easiest study to ever recruit for. Everybody wanted to come in because they were doing it already, and they wanted to know the answers. They wanted to know if the HIIT study or the HIIT exercise was okay for them to do. They were going to do it anyway, so we were just monitoring them as they were doing it.
That particular study was looking at 10 bouts of one-minute of very high intensity activity, which is 90% of maximal effort, followed by one minute of sort of active recovery at a lower intensity. And what we found is that it was extremely well tolerated by both the mother and the fetus, and that there were no adverse effects, no slowing of fetal heart rate. But also healthy birth outcomes afterwards as well. There’s a lot to do in that particular area. There are studies happening internationally now as a result of that work where they’re looking at training studies of high-intensity interval training during pregnancy to see if it’s a way to maintain fitness to improve pregnancy outcomes overall.
WHCC: Is it okay to start HIIT or lifting during pregnancy?
MD: I get that question all the time, and the very easy answer is we don’t know yet. In both of those studies, the women were previously engaging in HIIT before pregnancy, but also during their pregnancy. What we don’t have information about yet is what happens if you decide that you want to lift heavier weights during pregnancy, or you want to do higher intensity activity. Those studies have not been done yet. It’s certainly a question that we do need to answer to better support women who are pregnant.
WHCC: What does this study mean for professional sports and elite athletes moving forward?
MD: This is really important information for our professional and elite athletes. We’re seeing a number of athletes becoming pregnant mid-career and then wanting to return afterwards. And so one of the important things is that, similar to our general population, where we typically will see a reduction in physical activity levels as pregnancy progresses, again, totally fine if that’s what you’re choosing to do or if you start to experience any complications that would require it. But for our elite athletes, especially in our pro athletes, this is their job. That is an essential part of their work. So for many of them, being told to reduce their activity levels or to modify away from our high-intensity or heavy weight-lifting is really stressful.
We have done a number of interviews with elite athletes from around the world and they tell us that they want this information, they want this research because they’re often doing it, but the anxiety that comes with it is almost as harmful because they don’t know if what they’re doing is safer or not. So it starts to provide options and some additional guidance in terms of the types of training that they would normally do in their everyday lives to help support a maintenance of fitness, sports-specific skills as well to be able to continue to train during pregnancy, but also to support their return to sport in the post-prone period if that’s what they desire.
WHCC: Is it correct to assume that the longer you stay working out during pregnancy, the quicker you’re back to sport?
MD: We’re just starting to understand that particular aspect. So we have an upcoming study that’s just been accepted, and should be available online in the coming weeks, where what we did is look at what we call trajectory, physical activity across their pregnancies. Were they people who had this natural, slow decrease in their physical activity levels? Did they maintain their physical activity levels throughout their pregnancy? Or did they increase their training overall? What we found is that those individuals who had at least a 50% reduction in overall training volume, had twice the risk of having injury in the postpartum period. From a sports science perspective, when we think about people who are out of competition, for six to nine to 12 months or longer of time, you start to lose fitness, you start to lose sports-specific skills.
The neurocognitive way that your brain is functioning when you’re returning to your sport, is going to slow down and not function optimally when you do return. If there are ways that we can help support athletes to continue to train during their pregnancy, certainly they’re going to be modifications that are needed, and we’re still understanding that particular aspect, we do anticipate that that will help to support a better, less injured return to sport in the postpartum period.
WHCC: Can you elaborate on the cognitive benefits of remaining in the sport while pregnant?
MD: If you think about being on a soccer field and having a ball flying at you if you’re goalie – if you’re taken out of that situation for six to 12 months, or longer, you’re going to lose your reflexes, and your speed to be able to stop the ball. Same thing with most other sports. That reaction time will start to go away if you’re not training it. A lot of the work that I’m doing with some of the professional sports right now is finding ways that we can essentially help players to stay in-play, safely and evidence-based. Also recognizing that not only do we have to support the overall physical health of the athlete and the fetus, but we also have to support the mental health of the athlete as well.
If we’re asking all athletes to stop or reduce all sorts of training during their pregnancy, these are athletes whose part of their identity is to do their sport, and that can cause other downstream issues that we really haven’t reflected on enough as a research field or as a society. This does support their mental health for many athletes, to be able to continue some form of training. We just have to figure out what kind of training is safe and beneficial. Can we integrate some soccer-specific skills while they’re pregnant without increasing the risk of tripping, falling, or being hit by either their teammates or by a ball? We have a lot of work to do to support those particular athletes. We’re taking a much more holistic approach than really just focusing on one aspect of a person.
WHCC: What does this mean for elite athletes who are so in tune with their bodies?
MD: When we talk to our elite athletes, they’re often told when they’re pregnant to “do what your body tells you and listen to your body.” But you take them out of their sport and they’re pregnant for the first time, and they’re like, “I don’t know my body anymore.” So if there’s a way that we can help support that connection between the brain and their body while they’re pregnant, and maintain some sort of connection to their sport, it can be beneficial overall. We just have to do the research to be able to figure out how to best support these athletes.
WHCC: What was studied previously on pregnancy and sport?
MD: Shockingly little. Even today, the vast majority of the research that’s done on exercise during pregnancy and certainly exercise in the postpartum period is really focused on the general population. We typically will speak to one of the potential benefits of walking. When we talk about sport, it’s really only these trailblazing mothers that are becoming more and more visible. We know that there have been mothers in the Olympics since the very first Olympics in the early 1900s. We’re starting to see this increased visibility of women who are visibly pregnant during their sport, returning afterwards, bringing their babies, toddlers and older kids onto the pitch, by the pool, etc. That is really changing the conversation, and when we start to see it more in society, it does really stimulate a lot more research.
Even today, we have way too little information. And it comes directly from the athletes. They want this information. They need this research to be able to support them because they don’t necessarily believe our traditional ideas that you should take it back quite a lot while you’re pregnant. Answering those questions for them, whether we’re showing that it’s beneficial, whether we show that it’s maybe not so beneficial, and modifications need to be made, we do need to provide that evidence-based guidance to support these athletes while they’re pregnant and returning postpartum.
WHCC: Can you speak more about how elite athletes are involved?
MD: We’ve been extremely fortunate. I have athletes who contact me directly, who are excited to share their data. For example, we had an ultramarathoner. She is a very well-trained ultramarathoner. She has five kids and so she had Garmin data that she had collected over a twin pregnancy and a single pregnancy just a couple of years later.
She contacted me and said, “I have this information, I know you need this information, what can we do with it?” And so we worked with her, and we published a case study on this particular individual. She ran more than 13,000 kilometres over the course of her second (the single pregnancy) and a little bit less in her twin pregnancy, as you can imagine. But these are numbers that (I think I looked at it about five times just to be sure that the data was real) we don’t see. She got a lot of negative feedback about doing this during her pregnancy, even though for her, to support both her physical and mental health, and reduce her stress, this was the best thing for her. And her health outcomes were quite great.
WHCC: Do you get a lot of resistance?
MD: We get resistance from all sorts of directions. I couldn’t possibly pinpoint it to one specific group. We certainly get a lot of celebration and excitement from all areas, recognizing that our understanding of what can or should be done during pregnancy is going to change as the evidence comes out. Evidence is always really slow, and it’s certainly going to change as the years go by. I’ve been working in this field for 20, almost 25 years now, and it’s completely different recommendations and information from what we had 20 years ago. I can’t pinpoint exactly where the pushback is, but I think with education and a growing amount of research that we start to alleviate some of those key concerns. We just need to do more work, better work.
WHCC: You recently won the Drinkwater Leadership Award in Women’s Health, Sport & Physical Activity award. What does this win mean to you?
MD: It’s one of those things where I’ve spent my career, and when I was in grad school, I was often asked: “Why would you do exercise on postpartum women? We already know that exercise is beneficial, like this is not new.” But at the time, there was essentially no available information specific to the postpartum period. Our guidance was basically to get cleared at six weeks postpartum and then just go back to it – and we know that’s some of the most harmful messaging that we can have in the postpartum period.
Some people are not ready to go back in six weeks, and other people are ready to go back much sooner than six weeks postpartum. We’ve done a lot of work with my team over the last number of years, and with colleagues around the world, to try and answer questions. But you often feel like it’s just going into the void. Hopefully some people read this work, and hopefully some of our knowledge translation actually works. Barbara Drinkwater was the original leader supporting and pushing women’s health in sport and physical activity. Just being even associated with her name is a little bit shocking, and it just still doesn’t seem real. But it’s very meaningful.
WHCC: What would your wish be for women’s health? For women’s health research?
MD: I wish for investment into the research. It’s an incredibly difficult uphill battle. Most of us do a lot of this work on a shoestring budget. We do it as a passion. Our trainees are lucky enough to get scholarships, or they volunteer their time to be involved as undergrads.
If we had true, strong investment into women’s health research, it would make all the difference in the world. We wouldn’t just be slowly scratching the surface. We could actually answer the really hard questions. When we talk about my particular area, a lot of the work that we do – assessing the upper ends of what can or should be done for exercise during pregnancy – that’s completely unfunded. We don’t have the support to do that type of work. But when it gets out there, it starts to answer really important questions, and we see that there’s such a need and such a desire. We cannot do the research to the level that we want to if we don’t have the investment in women’s health research.
In Canada, to be able to get $50,000 a year to do this kind of work, you work for years to be able to do that. Most of my work is on a yearly basis. And a lot of it is working with students, who are lucky enough to get scholarships because they are so brilliant, to be able to support that work.
WHCC: Sounds like a lot of the time is spent finding funding.
MD: I would say, half my time is spent writing grants. We’re an exceptionally productive lab. Imagine if I got half of my time back, if I didn’t have to worry about how I can support my trainee in the second year of her project. We’re doing studies looking at postpartum exercise and bone health – really important questions that have never been looked at before – but to do it properly, the assessments are really expensive. So, I just say “okay, we’re gonna do it” and we’ll figure out how to pay for it later. It’s worked out okay so far, but you either answer the questions or you don’t, and you just have to get creative to find the ways. But if I had more time, my gosh!
