How Much Exercise Is Safe During Pregnancy? What to Avoid and When to Stop

How much exercise is safe during pregnancy?

In a healthy pregnancy, ACOG, the CDC and the World Health Organization advise at least 150 minutes of moderate-intensity aerobic activity a week, and the NHS says to aim for 150 minutes. ACOG says that if you are healthy and your pregnancy is normal, it is safe to continue or start regular physical activity, and that it does not increase your risk of miscarriage, low birth weight or early delivery.

Moderate means you can still talk but cannot sing, according to both ACOG and the NHS. ACOG says the 150 minutes can be split into 30-minute workouts on 5 days or 10-minute sessions through the day, and the 2019 Canadian guideline asks for activity on at least 3 days a week. ACOG still recommends talking about exercise with your ob-gyn at your early prenatal visits.

ACOG says regular exercise in pregnancy may lower your risk of gestational diabetes, preeclampsia and cesarean birth. The WHO's 2020 guidelines say physical activity in pregnancy does not increase the risk of stillbirth, newborn complications or problems with birth weight.

Is it safe to start exercising when you're pregnant?

Yes, if your pregnancy is healthy: ACOG says it is safe to start regular physical activity, as long as you begin slowly. ACOG suggests as little as 5 minutes a day, adding 5 minutes each week until you are active for 30 minutes a day. The NHS suggests starting with about 10 minutes a day and building up toward 150 minutes a week, and says that if you cannot manage 150 minutes, any activity is better than none.

ACOG names brisk walking, swimming and water workouts, stationary cycling, and modified yoga or Pilates as the safest choices. ACOG prefers a stationary bike to a standard bicycle, because your growing belly can affect your balance and make a fall more likely. The NHS says it is not recommended to start a new vigorous activity, such as running, in pregnancy.

Can you keep running or lifting weights while pregnant?

Usually yes, if you did them before you were pregnant. ACOG's committee opinion on exercise, reaffirmed in 2023, says women who regularly did vigorous aerobic activity or were physically active before pregnancy can continue during pregnancy, and the CDC and the WHO say the same. ACOG adds that experienced runners, joggers and racquet-sports players may be able to keep going after discussing it with their ob-gyn, and that if you start to lose weight you may need to eat more calories. NHS Best Start in Life differs on racquet sports: it lists tennis and squash, with martial arts, football and rugby, as exercise that risks your bump being hit.

For strength work, the NHS says muscle-strengthening exercise can include strength training at a gym if you already do it. The WHO and the Canadian guideline both recommend a mix of aerobic and strength activity. The WHO says anyone considering athletic competition or exercising well above the guidelines should be supervised by a specialist, and the Canadian guideline found no evidence on the safety or added benefit of exercising at those levels.

ACOG says pregnancy hormones relax the ligaments that support your joints, so jerky, bouncy or high-impact moves raise your risk of injury, and that the shift in your center of gravity puts stress on your pelvis and lower back (back pain in pregnancy covers what helps). The NHS says runners may find brisk walking more comfortable as the bump grows.

What exercises should you avoid during pregnancy?

ACOG says to avoid activities that put you at higher risk of injury:

• Contact sports and sports where you could be hit in the abdomen, such as ice hockey, boxing, soccer and basketball.
• Activities with a risk of falling, such as downhill skiing, water skiing, surfing, off-road cycling, gymnastics and horseback riding.
• Skydiving and scuba diving.
• Hot yoga or hot Pilates, which may cause you to overheat.
• Activity above 6,000 feet (about 1,800 m), unless you already live at high altitude.

The NHS adds mountain biking and rugby to the list of sports to avoid, and says not to exercise on an empty stomach, because it could make you faint. NHS Best Start in Life explains that scuba diving is not considered safe because your baby has no protection against decompression sickness.

ACOG says to avoid lying flat on your back as much as possible, because your uterus then presses on a large vein that returns blood to the heart, which may lower your blood pressure for a short time. The CDC and the WHO say to avoid exercising on your back after the first trimester, and the NHS says to avoid it for more than a few minutes, particularly after 16 weeks. The Canadian guideline says that if you feel light-headed, sick or unwell on your back, you should change position. Sleeping position in pregnancy covers the same issue at night.

ACOG also says to avoid overheating, especially in the first trimester, to drink plenty of water before, during and after exercise, and not to exercise outside when it is very hot or humid.

Who should not exercise during pregnancy?

The 2019 Canadian guideline from the Society of Obstetricians and Gynecologists of Canada and the Canadian Society for Exercise Physiology says you can keep up your usual daily activities but should not do more strenuous activity if you have one of these absolute contraindications: ruptured membranes, premature labor, unexplained persistent vaginal bleeding, placenta previa after 28 weeks, preeclampsia, an incompetent cervix, growth restriction of the baby, triplets or more, uncontrolled type 1 diabetes, uncontrolled high blood pressure, uncontrolled thyroid disease, or another serious heart, lung or whole-body condition.

For relative contraindications, the guideline says to discuss moderate or vigorous activity with your obstetric care provider first. It lists recurrent pregnancy loss, high blood pressure that starts in pregnancy, a past spontaneous preterm birth, mild or moderate heart or lung disease, symptomatic anemia, malnutrition, an eating disorder, twins after 28 weeks and other significant medical conditions. ACOG's committee opinion also limits its advice to pregnancies without obstetric or medical complications or contraindications.

When should you stop exercising and call your doctor or midwife?

ACOG says to stop and call your ob-gyn if you have any of these warning signs during exercise:

• Bleeding from the vagina
• Feeling dizzy or faint
• Shortness of breath before you start exercising
• Chest pain
• Headache
• Muscle weakness
• Calf pain or swelling
• Regular, painful contractions of the uterus (see signs of preterm labor)
• Fluid gushing or leaking from the vagina

The NHS also says to stop if you feel uncomfortable, too hot or unwell. The WHO says your healthcare provider should tell you the danger signs for stopping exercise, and that you should see a healthcare provider immediately if one occurs.