I have been a powerlifter for fifteen years, and I trained throughout my own pregnancy, including heavy compound lifts, right up until an emergency caesarean section. I am also a Consultant Obstetrician and Gynaecologist, and I spend my working life looking after women through every stage of their athletic lives: menstrual health, RED-S, fertility, pregnancy, and the return to sport afterwards.
That combination is unusual, and it is the reason I feel so strongly about this subject. When I was pregnant, I had fifteen years of training knowledge and a gynaecologist's understanding of exactly what was happening inside my own body. Most women have one of those things, or neither, and that gap is where the confusion lives.
The advice pregnant women are given about exercise still tends to sit at one of two unhelpful extremes: do nothing, or carry on exactly as before. Neither is right, and neither reflects what the evidence actually shows. Pregnancy does not make you fragile. The research is now very clear that for most women, regular activity in pregnancy is not only safe but actively protective, lowering the risk of gestational diabetes, pre-eclampsia, excessive weight gain and antenatal depression, with no increase in miscarriage or early pregnancy loss. Current guidance recommends at least 150 minutes of moderate-intensity activity a week, right through pregnancy. But pregnancy is not business as usual either. Load management matters, recovery matters, and knowing which movements to adapt, and when, is a clinical judgement, not a blanket rule.
Here are the five myths I hear most often in clinic, and what I actually tell my patients.
5 Pregnancy Exercise MythsMyth One
You shouldn't let your heart rate get too high
The idea that pregnant women must keep their heart rate below a fixed ceiling, usually quoted as 140 beats per minute, is one of the most persistent myths I hear, and it was never a good rule. It was dropped from formal guidance years ago, because a single number cannot possibly apply both to a lifelong runner and to someone who has never trained before. Modern guidance individualises intensity to the woman. The simplest tool is the talk test: if you can still hold a conversation while you move, you are working at a sensible intensity; if you cannot, ease off. If you prefer numbers, the 2019 Canadian guideline does give moderate-intensity heart-rate ranges — roughly 125 to 146 beats per minute for women under 30, and 121 to 141 for women aged 30 and over — but these are a guide, not a cage. Across the trimesters this looks different. In the first trimester, nausea and fatigue often bring your intensity down on their own, and that is fine. The second is usually when women feel strongest. By the third, heat, breathlessness and sheer load mean most women naturally dial things back, and that instinct is worth listening to. The watch is a tool, not the referee.
5 Pregnancy Exercise MythsMyth Two
You should stop lifting weights once you're pregnant
Well-managed strength training can continue for most women throughout pregnancy, and stopping abruptly is not automatically the safer option. For many women, lifting is a source of physical and mental stability at exactly the point they need it most, and the evidence supports resistance training as both safe and beneficial in pregnancy. What changes is how you lift, not whether you lift. Early on, if you feel well, you can often largely continue as you were. As the pregnancy progresses, I guide most women to move away from maximal, breath-holding efforts (heavy straining), to keep a couple of repetitions in reserve rather than training to failure, and to adjust their set-up as the bump changes their mechanics. By the third trimester, lighter loads with more control usually make sense. The principle is to manage the pressure through your abdomen and respect the changing body, not to down tools entirely. I say this as someone who kept lifting heavy throughout her own pregnancy. It can be done well. It should be done thoughtfully.
5 Pregnancy Exercise MythsMyth Three
If you were fit before, you can just carry on exactly as you were
This is the opposite myth, and it is just as unhelpful. Being fit beforehand does not exempt you from the fact that pregnancy changes what your body can absorb. Hormones such as relaxin increase the laxity of your ligaments, your blood volume and resting heart rate rise, your centre of gravity shifts forward as the bump grows, and you regulate heat differently. Practically, that means adapting continuously. In the second trimester, your changing centre of gravity affects balance and makes some single-leg and high-impact work harder; many women also develop pelvic girdle pain, which responds far better to modification and targeted strength work than to stopping altogether. From around the middle of pregnancy, if lying flat on your back makes you feel dizzy or unwell, modify those positions. I trained through my entire pregnancy and I still had to adjust constantly. Fitness is a brilliant starting point. It is not a free pass.
5 Pregnancy Exercise MythsMyth Four
Core exercises are off-limits entirely
Removing all core work is an overcorrection, and it is usually handed out as a blanket instruction rather than an individual assessment. A strong, well-coordinated deep core and pelvic floor are exactly what support your back and pelvis through pregnancy, and what help you recover afterwards. Some separation of the abdominal muscles, diastasis recti, is a normal, expected adaptation that occurs in the majority of women by the third trimester, not an injury to be feared. What matters is how you train. I steer women away from movements that cause visible doming or coning of the bump, and away from heavy crunch-type flexion and high intra-abdominal-pressure work as pregnancy advances, while actively keeping up breathing-led deep core and pelvic floor training. The goal is a core that functions well under load, not one that has been switched off for nine months.
5 Pregnancy Exercise MythsMyth Five
This kind of guidance is only relevant for elite athletes
This is the myth I find most damaging, because it is simply not true, and the people it leaves behind are the ones who need the information most. It is the woman who goes to the gym three times a week and has been told three different things by three different people. It is the runner told to stop entirely at twelve weeks with no clinical reason given. If anything, recreational exercisers have less access to specialist guidance than elite athletes do, not more. The guidelines are written for all active women, not a select few. You do not have to call yourself an athlete to deserve accurate, individualised advice about your own body.
5 Pregnancy Exercise MythsThe rule
The one rule that does matter
None of this means every symptom should be pushed through. Knowing the difference between discomfort that is normal and a signal worth listening to is exactly the clinical piece missing from most of the advice out there. Vaginal bleeding, leaking fluid, regular painful contractions, chest pain, calf pain or swelling, severe breathlessness, dizziness or headache are all reasons to stop and be assessed, not to carry on. If something does not feel right, that always warrants a proper assessment, not a generic rule. My job, really, is to close that gap: to give women the individualised, evidence-based guidance that lets them keep moving through pregnancy with confidence, whether they are lifting a barbell or simply trying to keep up their usual walk.
This piece offers general, evidence-based guidance, not personal medical advice. Every pregnancy is different, so please check with your own midwife, GP or obstetrician before making changes to how you exercise, and seek medical attention if any of the warning signs above appear.
References
- ACOG. Committee Opinion No. 804: Physical Activity and Exercise During Pregnancy and the Postpartum Period. Obstet Gynecol. 2020;135(4):e178-e188. https://pubmed.ncbi.nlm.nih.gov/32217980/
- Mottola MF, Davenport MH, Ruchat S-M, et al. 2019 Canadian Guideline for Physical Activity throughout Pregnancy. Br J Sports Med. 2018;52(21):1339-1346. https://www.apta.org/patient-care/evidence-based-practice-resources/cpgs/canadian-guideline-for-physical-activity-throughout-pregnancy
- Bø K, Artal R, Barakat R, et al. Exercise and pregnancy in recreational and elite athletes: 2016 IOC expert group evidence summary, Lausanne. Part 1. Br J Sports Med. 2016;50(10):571-589. https://research.bond.edu.au/en/publications/exercise-and-pregnancy-in-recreational-and-elite-athletes-2016-ev-2/
- Davenport MH, Kathol AJ, Mottola MF, et al. Impact of prenatal exercise on maternal harms, labour and delivery outcomes: a systematic review and meta-analysis. Br J Sports Med. 2019;53(2):99-107. https://pubmed.ncbi.nlm.nih.gov/30337349/
- WHO. Guidelines on Physical Activity and Sedentary Behaviour (2020): pregnant and postpartum women. https://www.ncbi.nlm.nih.gov/books/NBK566041/
- Benefits of Resistance Training During Pregnancy for Maternal and Fetal Health. Int J Womens Health.
