Throughout each of my three pregnancies, as my body transformed in unfamiliar ways, I found solace in movement. Walking gave me a sense of stability. Pilates allowed me to connect with my evolving body. Weight training empowered me. However, the emotional support I gained far outweighed the physical aspects. With challenges like preeclampsia, a late-term loss, and placenta previa, my pregnancies felt like obstacles. Yet, concentrating on what I could control—such as taking a walk or lifting a dumbbell—helped me manage the anxiety.
Historically, I recognize that I am fortunate: Less than four decades ago, women were generally advised to rest as much as possible during pregnancy. It wasn’t until 1985 that the American College of Obstetricians and Gynecologists (ACOG) issued its first exercise guidelines for pregnant women. Now, the organization recommends that most low-risk pregnant individuals “participate in aerobic and strength-conditioning exercises before, during, and after pregnancy.”
Since then, studies have uncovered numerous advantages of exercising during pregnancy for both the expectant mothers and their babies. “We now possess significantly more knowledge regarding the safety and effectiveness of physical activity,” states Rachel Tinius, Ph.D., an assistant professor of exercise science at Western Kentucky University, who studies the impact of exercise during pregnancy and ran the Boston Marathon while 12 weeks pregnant with her fourth child. “Research consistently shows that active mothers experience better delivery outcomes, improved fetal development, enhanced postpartum recovery, better mental health, regulated blood pressure, and a reduced risk of gestational diabetes,” all of which also benefitting the developing fetus, she adds.
Nevertheless, outmoded anxieties surrounding exertion during pregnancy persist. This might help explain why some estimates reveal that only 40% of pregnant women engage in exercise while expecting. Women who do remain active still face unsolicited remarks from family and even strangers expressing concern over their safety and that of their unborn child. In a social media poll I conducted about experiences with exercise during pregnancy, numerous women recounted tales of being warned by fellow gym members that performing weighted squats could result in the baby “falling out” (not true), or that excessive cardio could lead to hyperactivity in their future child (definitely incorrect). Some powerlifters reported being advised by physicians to switch to light 10-pound weights.
Kyle Georgina Marsh, a Pilates instructor and strength coach based in New York City, was taken aback when her obstetrician suggested reducing her activity level merely due to her pregnancy. When Marsh challenged this notion, her doctor responded, “You can continue these activities, but if you get injured or jeopardize your pregnancy, don’t say I didn’t warn you.” (Marsh subsequently changed her doctor.
Although the past four decades have seen significant growth in research surrounding exercise during pregnancy, the scientific community is still catching up for the previously absent data. Besides addressing past gaps, researchers are also striving to replace outdated misconceptions and fears with evidence-based insights. For instance, when ACOG released its inaugural physical activity guidelines for pregnant women in 1985, they advised that pregnant individuals should keep their heart rate below 140 beats per minute. This information was widely accepted in medical practices for years, despite lacking a scientific foundation, according to multiple researchers.
With very few studies on exercise and pregnancy available, obstetricians often settled on an arbitrary figure that seemed prudent, Tinius explains. “It was based on a group of knowledgeable doctors who decided to prioritize patient safety,” she says.
Current evidence indicates that for many pregnant women, exercising at a moderate-to-high intensity can be safe and even advantageous, especially if they were active prior to becoming pregnant. Nevertheless, several women I spoke with reported being advised— in 2024— to maintain their heart rate below 140 for no valid reason. This applies to lifting heavier weights as well. “We have significantly more knowledge today,” remarks Tinius, yet “just 30 years ago, the recommendations were entirely different.”
The shift in accepted wisdom regarding exercise during pregnancy over a single generation means that much of the previous guidance is still in circulation, and many remain hesitant to challenge it. “[Pregnancy] often brings immense stress, anxiety, and concern,” Tinius notes, making it easy for emotional responses to trump logical reasoning. The real challenge lies in bridging scientific advancements with the practical encouragement to stay active without fear.
“We face a crisis in disseminating information,” asserts Gráinne Donnelly, a pelvic floor physical therapist and editor of the Journal of Pelvic Obstetric and Gynaecological Physiotherapy. Her research reveals that many women receive no guidance on physical activity during pregnancy and postpartum. “It’s crucial that education and public health messaging improve in this respect.”
Additionally, outdated guidance has hindered researchers aiming to investigate exercise during pregnancy. “I believe the most significant hurdle [to further research] is the previously imposed limitations,” such as keeping pregnant women’s heart rates below 140 beats per minute, states Margie Davenport, Ph.D., a kinesiology professor at the University of Alberta, who leads a lab focused on research related to physical activity during and post-pregnancy. “Once societal norms impose these limitations, it becomes exceedingly difficult to propose studies, secure funding, and receive ethical approval.
“Many regard them as highly risky,” she remarks. “Yet, I believe the greater risk lies in neglecting the research.”
So, what insights do we have? To begin with, ACOG advises that expectant mothers engage in at least 150 minutes of moderate-intensity aerobic activity weekly, mirroring the recommendations for those who are not pregnant. Although the latest guidelines do not specify a precise amount of weekly strength training, ACOG asserts that strength conditioning is generally advantageous.
Researchers concur that for most women with low-risk pregnancies, maintaining active lifestyles can be an “exceptionally powerful” method to enhance health and well-being, according to Davenport. Staying physically active can alleviate back pain and constipation, bolster cardiovascular health, and lower the likelihood of gestational diabetes, preeclampsia, preterm labor, and cesarean sections. Some women even find that exercise mitigates nausea. Furthermore, engaging in physical activity during pregnancy can facilitate a quicker recovery afterward.
Importantly, for many women—especially those who exercised consistently before pregnancy—remaining active can enhance mental well-being, as noted by Davenport. In a 2021 study, her research team examined population studies regarding exercise’s effects on anxiety and depression during pregnancy and discovered that women who maintained high activity levels reduced their risks of both conditions by approximately 32% compared to control groups. “We’re just beginning to explore” the potential of exercise for mental health throughout pregnancy, she explains, largely because the scientific community has only recently focused on this aspect.
Physical activity during pregnancy also offers advantages for the fetus, emphasizes Dr. Cynthia Gyamfi-Bannerman, M.D., a maternal-fetal medicine professor at the University of California-San Diego, who co-authored ACOG’s latest exercise guidelines. This mutually beneficial dynamic is particularly evident regarding preterm births. “Stress is a significant contributor to preterm labor,” she notes, explaining that “exercise itself releases endorphins that help alleviate stress.”
Even if exercise doesn’t ward off complications or undesirable outcomes, it can still provide benefits by helping pregnant individuals feel better, calmer, and stronger. This was true in my experience. Despite remaining active throughout my pregnancies, I encountered several complications—yet I firmly believe that my routine helped me manage these challenges far more effectively than I would have if I had been inactive.
The knowledge gaps scientists are striving to address are notably pronounced at both ends of the exercise continuum, says Davenport. This includes expectant individuals with medical issues for which doctors advise against exercise, and elite athletes aiming to maintain high training levels throughout pregnancy. “For those with exercise contraindications, our knowledge is quite limited,” Davenport remarks. “Many contraindications are theoretical rather than evidence-based. However, that research is certainly progressing.”
Interestingly, more than two dozen athletes have succeeded in competing in the Olympics while pregnant, with several winning medals.
Conversely, the other end of the spectrum involves athletes who frequently surpass existing recommendations with prolonged, high-intensity training. Davenport points out that this area is still largely uncharted. This lack of information can pose challenges for elite athletes who wish to continue training or competing during pregnancy. “It induces significant anxiety and often distress because we don’t have definitive evidence regarding safe limits,” she explains.
Dr. Megan Roche, M.D., Ph.D., an Olympic trail runner who researches and coaches pregnant athletes, concurs. “That question still looms large for me,” she states. “If an athlete goes for an all-out 5K, we lack sufficient evidence to determine how this impacts a developing fetus.”
While research is catching up, many pregnant athletes proceed with competitions, relying on their instincts. Serena Williams notably triumphed at the 2017 Australian Open while pregnant, and elite runners continue to win races during their pregnancies. Over two dozen athletes have participated in the Olympics while pregnant, with several earning medals.
Both Davenport and Roche emphasize the necessity for more high-quality studies, which can be difficult to execute since they may require pregnant women to exceed currently sanctioned medical guidelines.
Nevertheless, not every pregnant individual should push their physical limits. Following the release of Jane Fonda’s pioneering pregnancy workout in the 1980s, fitness culture has since embraced exercise during pregnancy. To be pregnant in 2024 means encountering a plethora of images and videos featuring women working out up until their due dates, often showcasing visible abs over their baby bumps. As pregnant athletes become increasingly visible—crossing marathon finish lines, engaging in CrossFit, and leading fitness classes—some women may feel pressured to maintain intense workout routines as if they weren’t pregnant. Exercise can transform into yet another task on an exhaustive list of pregnancy wellness priorities. Women who genuinely need to limit their activity for health reasons may become anxious about the consequences of reduced movement.
In the vibrant encouragement for pregnant women to engage in exercise, the subtleties of the actual experience during pregnancy are often overlooked. The truth is that as pregnancy progresses, women’s bodies undergo significant visible and hidden changes that can dramatically influence their exercise routine and movement. Experts emphasize that recognizing these changes can alleviate anxiety about working out and help in setting realistic fitness goals. A key aspect affected is the cardiovascular system; during pregnancy, resting heart rates increase, and even light activities—like walking uphill—can result in significant heart rate spikes. This shift is partly due to a near doubling of blood volume, requiring the heart to pump harder to supply both the body and the developing fetus. “Pregnancy is like a stress test,” states Gyamfi-Bannerman. “Essentially, it’s akin to being subjected to a stress test for nine months.” It’s demanding.
Additionally, fatigue and nausea present challenges even for the most determined fitness enthusiasts. “The first trimester can be particularly tough,” remarks Roche. “I’ve observed athletes having difficulty maintaining their routine post-first trimester, despite feeling better in the second. Sometimes, resuming exercise can be quite challenging.”
Hormonal shifts, notably the increase in relaxin, also contribute to changes as this hormone causes joints and ligaments to become more elastic and unstable, especially during the third trimester. While this is beneficial for uterine expansion and childbirth, it can complicate certain workouts. “With athletes I’ve assisted, I’ve noticed a number of rolled or sprained ankles because of ligament instability,” Roche points out. Moreover, issues like pelvic and hip pain, as well as back pain, are common.
As pregnancy advances, lying flat on the back may induce breathlessness due to the growing uterus putting pressure on a major artery that supplies oxygen to the brain. It is advisable to avoid this position for extended periods. Additionally, as the uterus expands, you might experience shifts in your center of gravity.
“Maintaining your balance will feel different than it did pre-pregnancy,” Gyamfi-Bannerman notes. “Acknowledging this and adjusting your activities accordingly is essential.” Many pregnant women find additional support through belly bands or compression garments, such as supportive leggings or bike shorts, during physical activities.
Ultimately, Roche advises listening to your body while pregnant and asking yourself: How does this feel? Does it seem sensible? “It can be anxiety-inducing to see heart rate data on a run. Constantly monitoring that can be overwhelming. It raises questions about your heart’s performance,” she explains. The guidance surrounding exercise during pregnancy has become “more intuitive towards the body’s needs.”
If you were very active prior to pregnancy and can sustain your workout without adverse effects, continuing your current routine may be appropriate. However, for those new to exercise, “it’s essential to ease into it and gradually build up,” she suggests.
The experts I consulted reinforced that an exercise regimen during pregnancy need not resemble an intense gym workout. Activities like walking, practicing yoga, and even completing errands can be incredibly beneficial. “While there’s frequent mention of achieving 150 minutes of moderate-intensity activity,” Davenport explains, “it’s often overlooked that significant benefits can arise from engaging in much less activity.” Any movement is superior to inactivity.
They also stressed that each individual body, and each pregnancy, is unique. “You truly cannot measure yourself against others, because their experiences and bodies differ remarkably from yours,” Tinius asserts. “Being mindful of your body’s journey and allowing yourself grace throughout the process” can assist in directing your focus on what suits you best, Roche adds. “It won’t be the same for everyone.”
Danielle Friedman is an award-winning journalist specializing in health, sexuality, and culture. She is the author of Let’s Get Physical: How Women Discovered Exercise and Reshaped the World. Her work has appeared in various reputable outlets including The New York Times, The Cut, Vogue, Glamour, Harper’s Bazaar, the Washington Post, NBC News, InStyle, and Health. Previously, she has also contributed to Romper, discussing topics like how to revamp one’s relationship with exercise and the implications of teens using Ozempic for weight management.
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