Exercise in pregnancy is safe for most women, and most don’t get enough

Key takeaways

• In the trials behind Canada’s 2019 pregnancy guideline, regular exercise lowered the odds of gestational diabetes by 38%, or about 39 fewer cases for every 1,000 women, without raising the odds of miscarriage or preterm birth¹.
• U.S. guidelines call for at least 150 minutes a week of moderate activity in pregnancy and the year after birth, and women who already ran or did other vigorous exercise can usually continue³.
• Stop and call your clinician for vaginal bleeding, fluid leaking, chest pain, dizziness, headache, calf pain or swelling, contractions or less movement from the baby⁴.
• Pelvic floor exercises started in pregnancy, before any leaking, probably cut the risk of bladder leaks late in pregnancy by more than half, a 2020 Cochrane review found⁸.
• After birth, English hospital physiotherapists suggest building up in stages and waiting at least 12 weeks before running or other impact sports¹⁰.

In a University of Alberta lab, 10 pregnant women did barbell squats, bench presses and deadlifts as the weight rose set by set. On the last round, they held their breath to brace⁵⁶. All the while, an ultrasound tracked each baby’s heart rate and the blood flow in the umbilical cord⁵.

The babies’ heart rates didn’t slow down or speed up. Cord blood flow stayed normal, even during bench presses done lying on the back⁶. The study had clear limits: one session, 10 pregnant women, and only women with at least two years of lifting experience⁶.

Heavy lifting is a narrow question. The bigger one is whether pregnant women move enough. The authors of Canada’s 2019 pregnancy activity guideline wrote that fewer than 15% of women reach the minimum of 150 minutes a week¹. The risks of inactivity, they argued, had not been stressed enough¹.

U.S. numbers are only a little kinder. In national surveys from 2007 to 2014, about 13% to 45% of pregnant women reported enough activity to meet ACOG’s advice, depending on how strictly it was counted¹⁵. Self-reports also tend to run high¹⁵.

That matters if you value prevention without pills. Below, we cover how much to do, what to skip, the signs to stop and how to come back after birth.

U.S. and Canadian guidelines set the same weekly target

Three major sources agree on the basics for women without complications.

• ACOG, 2020. The American College of Obstetricians and Gynecologists (ACOG) updated its advice in Committee Opinion 804, published in April 2020. It added guidance for athletes, and its lead author said the evidence supports encouraging both aerobic and strength exercise².
• U.S. federal guidelines, 2018. The Physical Activity Guidelines for Americans call for at least 150 minutes a week of moderate activity in pregnancy and the first year after birth, such as 30 minutes on 5 days³. Women who already ran or did other vigorous exercise can keep going³.
• Canada, 2019. A joint guideline from the Society of Obstetricians and Gynaecologists of Canada and the Canadian Society for Exercise Physiology asks for at least 150 minutes spread over at least 3 days¹. It recommends mixing aerobic and strength exercise, and it includes women who were inactive before pregnancy¹.

Moderate means you breathe harder but can still hold a conversation. The Canadian guideline calls this the talk test¹. You don’t need long sessions: short chunks count, and some activity beats none, the Centers for Disease Control and Prevention (CDC) says³.

What 104 trials found: fewer complications and no added harm

The Canadian team screened 27,624 titles and based its advice mainly on 104 randomized controlled trials, in which women are assigned by chance to exercise or usual care¹. Here is what regular prenatal exercise did, shown both ways¹:

Outcome	Change in odds	Per 1,000 women
Gestational diabetes	38% lower	39 fewer cases
Preeclampsia, a dangerous blood pressure disorder	41% lower	12 fewer cases
New high blood pressure in pregnancy	39% lower	15 fewer cases
Depression during pregnancy	67% lower	134 fewer cases
A newborn much larger than average	39% lower	30 fewer cases

Watch the last column. A 41% drop in preeclampsia odds sounds enormous, but it means about 12 fewer cases per 1,000 women¹.

Safety held up as well. Exercise didn’t raise the odds of miscarriage, preterm birth or low birth weight, and activity in the first trimester wasn’t tied to more miscarriages or birth defects¹. ACOG’s 2020 update also said exercise may lower the risk of cesarean birth and can help prevent postpartum depression².

Walk, swim, cycle and lift. Skip scuba and contact sports

The federal Office on Women’s Health (OWH) lists walking, swimming, dancing, cycling and low-impact aerobics as good choices⁴. If you jogged, played racquet sports or lifted weights before pregnancy, your doctor may okay keeping them up⁴.

U.S. and Canadian sources agree on a short list to avoid¹⁴:

• Sports where your belly could be hit, such as kickboxing, soccer, basketball and ice hockey⁴.
• Activities with a high risk of falls, such as horseback riding, downhill skiing and gymnastics. The Canadian list adds outdoor cycling and Olympic-style lifts¹⁴.
• Scuba diving. The Canadian guideline cites decompression sickness, and OWH warns of gas bubbles in the baby’s blood¹⁴.
• Hard exercise in heat. Avoid vigorous effort in extreme heat or humidity, and drink fluids before, during and after¹⁴.
• Lying flat on your back after the first trimester. OWH says the position can squeeze a major vein and cut blood flow to the baby³⁴.

As your belly grows, your balance shifts, so jogging, cycling and racquet sports may get riskier late in pregnancy⁴.

The sources differ on two points. On altitude, OWH says not to exercise above 6,000 feet⁴.

The Canadian guideline says moderate activity at 6,000 to 8,250 feet doesn’t appear to cause problems once you’ve acclimatized. It advises women who live lower down to avoid activity above about 8,250 feet. Anyone considering it should seek supervision from an obstetric care provider¹.

The back-lying rule is also softer in the Canadian version. It rates the evidence as very low and simply asks women to change position if they feel lightheaded, sick to the stomach or unwell while flat on their backs¹.

When to hold off, and when to stop

For some women, exercise isn’t safe right now. The Canadian guideline lists these as reasons not to exercise: waters that have broken, preterm labor, unexplained ongoing vaginal bleeding, placenta previa after 28 weeks, preeclampsia, a cervix that opens too early, a baby who isn’t growing well, triplets or more, and uncontrolled type 1 diabetes, high blood pressure or thyroid disease¹.

Other conditions call for a plan made with your clinician. These include repeated pregnancy loss, high blood pressure in pregnancy, a past preterm birth, anemia with symptoms, malnutrition, an eating disorder and twins after 28 weeks¹. If food or exercise feels hard to control, the National Alliance for Eating Disorders helpline, 1-866-662-1235, connects callers with licensed therapists on weekdays¹⁴.

Strength training is encouraged, and heavy lifting is getting tested

Light to moderate strength work is already encouraged in pregnancy, the Alberta researchers note⁵, and the Canadian guideline pairs it with aerobic exercise¹. Heavier loads are less settled. The Canadian authors wrote that evidence above the recommended levels is lacking and advised high-intensity work only in a monitored setting¹.

The Alberta study was built to test that gap. The pregnant women were 22 to 31 weeks along and worked up to loads above 75% of the most they could lift once, with and without a breath-hold⁶. All nine followed to delivery gave birth at term, and the babies averaged 3,433 grams, about 7.6 pounds by our math⁶.

Loads above about 85% of that maximum went untested⁶. A Canadian government science grant and a University of Alberta health research institute paid for the work, and the authors declared no competing interests⁵⁶.

A second study from the same research group surveyed 679 people who had lifted at least 80% of their one-lift maximum while pregnant⁷. Most were recreational athletes, and 61% did CrossFit⁷. Two-thirds reported no pregnancy or delivery complications, and those who kept their usual training until delivery reported fewer complications⁷.

Outcomes looked similar with or without Olympic lifts, lifting while lying on the back, or a breath-hold⁷. But 57% reported bladder leaks after pregnancy⁷. A survey of self-selected volunteers with no comparison group can’t show what caused either result.

If you lift seriously, bring these studies to your clinician. Our article on breathing during exercise explains the breath-hold, called the Valsalva maneuver.

Pelvic floor training works best before leaks start

Your pelvic floor muscles support the urethra, vagina and rectum⁴. Training them is cheap and drug-free.

A 2020 Cochrane review, from the independent network that pools medical research, gathered 46 trials with 10,832 women in 21 countries⁸⁹. In women who weren’t leaking, starting training in pregnancy lowered the risk of bladder leaks late in pregnancy (risk ratio 0.38, six trials)⁸. By our math, that’s about 62% lower risk. Three to six months after birth, the risk was about 29% lower, by our math (risk ratio 0.71, five trials)⁸.

For women already leaking in pregnancy, the review found no clear benefit from training started then⁸⁹. Broad programs offered to everyone after birth didn’t reliably cut leaks either⁸. And about one in five women still leak gas or stool a year after birth, with no clear evidence yet that training prevents it⁹.

The Canadian guideline advises daily pelvic floor training with instruction on technique¹. OWH’s version: tighten the muscles for a count of three, relax for three, and repeat 10 to 15 times, three times a day, starting out lying down⁴. Our rehabilitation article covers treatment for leaks that don’t go away.

After birth, rebuild in stages and at your own pace

CDC counts the whole first year after delivery as postpartum, with the same 150-minute goal³. U.S. guidance says little about pacing: ACOG’s 2020 release mainly urges close physician supervision for athletes returning to hard training².

For a step-by-step path, physiotherapists at Oxford University Hospitals in England offer a rough sequence in a 2025 leaflet¹⁰. It starts with pelvic floor work, gentle core exercises and short walks, then adds bodyweight moves, low-impact cardio, faster walks and resistance¹⁰.

Their advice is to wait at least 12 weeks before running or impact sports, which they call a rough guide rather than a target¹⁰. Before a first run, they suggest you be able to walk 30 minutes, stand on one leg for over 10 seconds and jog in place for a minute, all without symptoms¹⁰.

After a cesarean. A Milton Keynes University Hospital leaflet allows 6 to 8 weeks or more to recover, with no heavy lifting for 6 weeks¹¹. Early on, it suggests deep breathing to help prevent a chest infection, ankle exercises to help prevent clots and a short walk each day¹¹. Contact your midwife or doctor if the wound is red, hot or leaking, or if pain isn’t settling¹¹.

Breastfeeding. The Oxford team suggests exercising soon after a feed or pumping session, when breasts are less full, in a supportive sports bra¹⁰.

A gap in the belly muscles. After pregnancy, the two sides of the “six-pack” muscle can pull apart, a gap called diastasis recti. Walking during pregnancy was tied to lower odds of developing it¹. If you have a visible gap, the Canadian guideline advises physiotherapy advice and no abdominal curls¹. The Milton Keynes leaflet says a small gap often recovers in 4 to 8 weeks, while a larger one can take 6 to 12 months with specialist help¹¹. It also says to avoid sit-ups and crunches¹¹. Neither source cites trials for specific exercises, so treat them as expert practice, not proven treatment.

Signs to ask for help. The Oxford team lists leaking urine or stool, a heavy or dragging feeling in the vagina, a dome or bulge along the belly, or pain¹⁰. Ask for a referral to a pelvic health physiotherapist if these appear¹⁰.

Mood. CDC says activity after birth eases symptoms of postpartum depression³. Whether it prevents a diagnosis is less clear.

The U.S. Preventive Services Task Force (USPSTF) found mixed trial results in 2019. Its April 2025 draft, still not final in October 2026, called them encouraging but too limited to recommend¹². For people at higher risk, it recommends counseling, such as cognitive behavioral therapy¹². Our companion article on pregnancy and postpartum sleep covers it.

If low mood or worry lingers, call or text the National Maternal Mental Health Hotline at 1-833-852-6262 (1-833-TLC-MAMA). It’s free, confidential and open 24/7 in English and Spanish¹³. If you’re thinking about harming yourself, call or text 988.

The pregnancy activity plan

Movement fits what many natural-health readers want from care: no prescription, low cost, and something you control. The evidence backs that instinct here. It also asks you to respect your body’s signals, by resting when a stop sign appears and treating a clinician’s “not right now” as part of the plan.

Use this plan as a starting point with your clinician. It assumes no complications.

Stage	What to do	What to avoid	Stop and call if	Sources
First trimester	Keep or start 150 minutes a week; walking, swimming, cycling; daily pelvic floor work	Scuba, contact sports, hard effort in heat	Bleeding, belly pain, dizziness	134
Second trimester	Add or keep strength work; talk-test effort	Lying flat on your back; fall-prone sports	Fluid leaking, calf pain or swelling, headache	14
Third trimester	Lower-impact options as balance shifts; swimming, stationary bike	Jerky or bouncing moves; altitude without acclimatizing	Contractions, less baby movement, chest pain	14
Birth to 6 weeks	Pelvic floor, gentle core, short walks; after cesarean, breathing and ankle moves	Heavy lifting; sit-ups and crunches	A red, hot or leaking wound; pain that isn’t settling	1011
6 to 12 weeks	Faster walks, added resistance, swimming once wounds heal	Running and jumping	Leaks, vaginal heaviness, belly doming, pain	10
12 weeks and later	Graded return to running and sport	Rushing past symptoms	Same signs as above	10

How strong is the evidence?

Claim	Rating	Why
Moderate exercise is safe for pregnant women without complications	Strong evidence	104 trials; no rise in miscarriage, preterm birth or low birth weight1
Exercise lowers gestational diabetes and preeclampsia	Strong evidence	39 and 12 fewer cases per 1,000 women1
Pelvic floor training before leaks prevents them	Strong evidence	Moderate- and high-certainty Cochrane results8
Exercise eases depression in pregnancy and after birth	Promising but early	Fewer prenatal cases in trials; prevention after birth unproven112
Heavy lifting is safe for experienced lifters	Promising but early	One lab study of 10 pregnant lifters and one self-selected survey67
Specific exercises close a belly-muscle gap after birth	Not enough evidence	Advice rests on expert practice; the guideline and leaflets we reviewed cite no trials111
Scuba diving in pregnancy	Evidence says no, or unsafe	Guidelines cite decompression sickness and gas bubbles14

Questions readers ask

The bottom line

For most pregnant women, the safer choice is to move. Regular moderate activity lowers the odds of gestational diabetes, preeclampsia and depression in pregnancy, and it doesn’t raise the odds of miscarriage or preterm birth. Scuba, contact sports, fall-prone activities and hard effort in heat are the main exceptions, and a short list of warning signs means stop and call.

After birth, rebuild in stages and let symptoms, not the calendar, set the pace. Pelvic floor training is worth starting early. Heavy lifting has encouraging but small studies behind it, so plan it with your clinician.

Keep exploring: sleeping on your back while pregnant.

Related reading

• Exercise benefits start below 150 minutes and keep rising well past it
• Most back pain fades on its own, and dizziness and bladder leaks respond to rehab
• Breathing takes care of itself in most workouts, but lifting, side stitches and asthma need a plan
• Insulin has a team that pushes back, as puberty and pregnancy show
• Side-sleeping advice begins at 28 weeks, and before that, back-sleeping wasn’t linked to harm

Sources

1. Mottola MF, Davenport MH, Ruchat S-M, et al. “2019 Canadian Guideline for Physical Activity Throughout Pregnancy.” British Journal of Sports Medicine, 2018;52(21):1339–1346 (joint guideline of the Society of Obstetricians and Gynaecologists of Canada and the Canadian Society for Exercise Physiology; funded by the Canadian Institutes of Health Research). pubmed.ncbi.nlm.nih.gov
2. American College of Obstetricians and Gynecologists. “ACOG Releases Updated Guidance on Exercise in Pregnancy and Postpartum, Includes Recommendations for Athletes” (on Committee Opinion No. 804, Obstetrics & Gynecology, April 2020). News release, 2020. acog.org
3. Centers for Disease Control and Prevention. “Pregnant & Postpartum Activity: An Overview” (based on the Physical Activity Guidelines for Americans, 2nd edition, 2018). Last reviewed December 4, 2025. cdc.gov
4. Office on Women’s Health, U.S. Department of Health and Human Services. “Staying Healthy and Safe.” Last updated September 26, 2025. womenshealth.gov
5. MacPherson A. “Study Confirms Safety of High-Intensity Resistance Training During Pregnancy.” Folio, University of Alberta, March 12, 2025. ualberta.ca
6. Moolyk AN, Wilson MK, Matenchuk BA, et al. “Maternal and Fetal Responses to Acute High-Intensity Resistance Exercise During Pregnancy.” British Journal of Sports Medicine, 2024 (online), doi:10.1136/bjsports-2024-108804 (copy of the published article opened at a third-party host). fisiologiadelejercicio.com
7. Prevett C, Kimber ML, Forner L, De Vivo M, Davenport MH. “Impact of Heavy Resistance Training on Pregnancy and Postpartum Health Outcomes.” International Urogynecology Journal, 2023;34(2):405–411 (Sheffield Hallam University repository record). shura.shu.ac.uk
8. Woodley SJ, Lawrenson P, Boyle R, et al. “Pelvic Floor Muscle Training for Preventing and Treating Urinary and Faecal Incontinence in Antenatal and Postnatal Women.” Cochrane Database of Systematic Reviews, 2020, CD007471.pub4 (Newcastle University record). eprints.ncl.ac.uk
9. Vnenchak P. “Pelvic Floor Muscle Training to Prevent and Treat Urinary and Fecal Incontinence in Antenatal and Postnatal Patients” (Cochrane for Clinicians). American Family Physician, 2021;104(3):234–235. aafp.org
10. Women’s and Men’s Health Physiotherapy, Oxford University Hospitals NHS Foundation Trust. “Returning to Exercise and Sport After Childbirth.” Patient leaflet, January 2025. ouh.nhs.uk
11. Milton Keynes University Hospital NHS Foundation Trust. “Diastasis Recti Following Pregnancy” (updated February 2023) and “Advice and Exercises Following Caesarean Section” (updated August 2023). Patient leaflets. mkuh.nhs.uk and mkuh.nhs.uk
12. U.S. Preventive Services Task Force. “Perinatal Depression: Preventive Interventions.” Final recommendation, February 12, 2019; and draft recommendation, April 22, 2025. uspreventiveservicestaskforce.org and uspreventiveservicestaskforce.org
13. Health Resources and Services Administration, Maternal and Child Health Bureau. “National Maternal Mental Health Hotline.” Accessed October 2026. mchb.hrsa.gov
14. National Alliance for Eating Disorders. “What Is an Eating Disorder Helpline?” April 14, 2023, accessed October 2026. allianceforeatingdisorders.com
15. Hesketh KR, Evenson KR. “Prevalence of U.S. Pregnant Women Meeting 2015 ACOG Physical Activity Guidelines.” American Journal of Preventive Medicine, 2016;51(3):e87–e89. pmc.ncbi.nlm.nih.gov