Is Exercise Important in Pregnancy?
Regular physical activity is one of the most important actions individuals, including pregnant individuals, can take to improve their health [1-5]. Exercise during pregnancy can improve multiple pregnancy outcomes, in addition to its general health benefits [6,7]. The American College of Obstetricians and Gynecologists (ACOG) and other international organizations recommend that in the absence of contraindications, pregnant individuals should continue or commence exercising, emphasizing that exercise is an important component of optimal health maintenance [8].
Most Common Exercise Recommendation
A generally accepted recommendation is 150 minutes of moderate intensity physical activity per week minimum.
Exercise Cautions
There are some complications that can make certain exercises unsafe. It is important that pregnant individuals are carefully monitored for complications before recommendations are made regarding physical activity [11]. Even in healthy pregnancies, exercise routines may have to be modified during pregnancy to accommodate normal pregnancy-related anatomic and physiologic changes and to avoid adverse fetal effects.
Barriers to Exercise in Pregnancy
Oftentimes the largest challenge to exercise in pregnancy are nausea and fatigue; certain changes can be made to help accommodate for these [12].
Benefits of Exercise in Pregnancy
General overall health improvement
Improves heart health, lung health, muscular strength, endurance, flexibility [13-17].
Helps maintain healthy pregnancy weight [18-23].
Reduces pregnancy-related low back and pelvic pain [23,25].
Pelvic floor muscle exercises help prevent urinary incontinence
Lowers risk of macrosomic (overly large) newborn [23].
Lower risk of high blood pressure in pregnancy (3% risk versus 5% risk with no exercise) [28]
28% lower risk of diabetes [23]
Lower complications of preeclampsia, preterm birth, and C-section
Risks — Potential risks of exercise in pregnancy include:
Maternal trauma, which may lead to an obstetric complication, such as placental abruption, and thus impact the fetus.
Risk of joint/ligament injury (due to progressive changes in ligament flexibility from hormonal changes)
Heat stroke: Some research suggests that overheating, or excessively high body temperature (>102.2°F; 39°C) in early pregnancy, especially the first four to six weeks, may pose a risk of harm to the baby [29,30]. However, this is unlikely with normal exercise in healthy individuals.
Common Exercise Guidelines
Exercise recommendations are extremely individualized. It is difficult to give one solution to everyone. It is important to talk to a health professional to discuss what is best for you (such as a doctor, midwife, obstetrician, or naturopathic doctor who focuses in this area). Nonetheless, here are some common recommendations given:
Type of program | Duration, frequency | Optimal intensity | To be avoided |
Low-impact aerobic exercise | |||
Walking, aerobic dancing, stationary cycling, jogging (in previously active women), or swimming | 20 to 30 minutes, 3 to 5 days/week | Moderate as ideally controlled via heart rate 80% or less of maximum heart rate; or a rate of perceived exertion 13-14 on the Borg scale*, or the talk test (you should be able to talk but not sing during the activity). | High-intensity (>90% of maximum heart rate); strenuous exercise; long-distance running; exercises with risk of falls or impact of the body against the ground or hard surfaces (jumping or quick changes of direction), or physiological danger (eg, diving) |
Strength exercise (toning) | |||
Resistance bands, dumbbells, body weight exercises involving large muscles | 15 to 20 minutes, 3 to 5 days/week | Light to moderate loads (eg, 1 to 2 sets of 10 to 15 repetitions using 1- to 3-kg dumbbells) | Isometric exercises, Valsalva maneuver, frequent heavy weight lifting, hot yoga or pilates, supine position exercises |
Pelvic floor muscle training (Kegel) | 10 to 15 minutes, 3 to 5 days/week | Approximately 100 repetitions | |
Combination of the low-impact aerobic and strength exercises (highly recommended) | |||
Low-impact aerobic and strength exercises combined (eg, aerobic dancing followed by use of dumbbells) | 45 to 65 minutes, 3 to 4 days/week | Same as for low-impact aerobic and strength exercises | Same as for low-impact aerobic and strength exercises |
*The Borg scale quantifies ratings of perceived exertion from a minimum score of 6 (very, very light) to a maximum of 20 (very, very hard), with a score of 13 to 14 denoting moderate intensity (ie, somewhat hard).
What is Maximum Heart Rate
Maximum heart rate is usually calculated as 220 minus your current age.
Warm-Up and Cool-Down
Each exercise session should also include an initial warm-up and a final cool down period that is around 5 minutes each.
Sedentary Individuals
If before your pregnancy you were not very active, it is a good idea to seek assessment and advice from an experienced health professional regarding what exercises would be safe to start with.
Other Considerations
There are other factors that may affect risk of complications and injuries. A thorough evaluation from a health professional should include your medical history, current medical condition and medications, past and present pregnancy-related complications, and current exercise and physical activity levels. For each exercise, a health professional can help guide you on recommended exercise intensity, frequency, and duration.
Contraindications to Exercise during Pregnancy
While exercise is safe for most pregnant individuals, those with some preexisting or developing medical conditions may have to restrict or avoid exercise.
Absolute contraindications to aerobic exercise during pregnancy:
Heart disease
Restrictive lung disease
Persistent second- or third-trimester bleeding
Premature labor during the current pregnancy
Ruptured membranes
Preeclampsia or pregnancy-induced high blood pressure
Severe anemia
Potential contraindications to aerobic exercise during pregnancy (requires assessment by health professional):
Anemia
Ruptured membranes
Chronic bronchitis
Poorly controlled type 1 diabetes
Extreme morbid obesity
Extreme underweight (BMI less than 12)
History of extremely sedentary lifestyle
Intrauterine growth restriction in current pregnancy
Poorly controlled high blood pressure
Low blood pressure
Poorly controlled seizure disorder
Poorly controlled hyperthyroidism
Heavy smoker
This is not an exhaustive list and it is a good idea to talk to a health professional to determine whether there are any contraindications to exercise during your pregnancy.
General Activities to Avoid in Pregnancy
Activities with high risk of falling or collision, especially abdominal trauma (eg, full contact sports) are contraindicated because of risk of injury to the placenta and mother
Activities that require jumping movements or quick changes in direction. This can stress joints and increase the risk of joint injury due to hormonal changes in pregnancy that can cause ligament laxity (hyper flexible ligaments). This means joints are supported less effectively, especially in individuals with poor muscle mass. Activities should be modified and completed with caution.
Hot yoga should be avoided (regular yoga is considered safe [62-64]). Also, avoid yoga positions that are uncomfortable or likely to result in loss of balance and falling.
Avoid dehydration from prolonged intense exercise. Hydration is particularly important while pregnant
Limit exposure to less than 32° C
Avoid Exercises While Lying Down (Supine)
It is a good idea to avoid exercises while lying down because the baby can put pressure on the mother’s major blood vessels. This position can cause low blood pressure episodes in 10 percent of pregnant individuals, especially in the third trimester.
This position can compromise blood flow to the uterus due to compression of the aorta. That being said, the risk is mostly when lying down at rest rather than with exercise while laying down [65]. So far adverse pregnancy effects from exercising while laying down have not been proven in research [66]. However, it may be a good idea to err on the side of caution.
Modifying Supine Exercises
When possible, complete supine exercises while tilting the torso to 45 degrees, lying on the side, sitting, or standing.
Strength Training
Strength training can be done during pregnancy, but information about safety is limited.
Due to the risk of joint injury from increased relaxation of joints and ligaments, most studies use low-intensity resistance training with low weights (free weights or machine, ≤10 pounds) with multiple repetitions lifted through a dynamic range of motion. These studies have found this to be safe in pregnancy [67,68].
Although research is limited, a prudent approach is to avoid heavy-resistance weight lifting, any exercises that result in marked straining, training to failure, and intense repetitive isometric exercises during pregnancy.
Why is Heavy Strength Training Avoided in Pregnancy?
Heavy strength training can cause the abdominal muscle to activate and tighten. During pregnancy this causes a rapid increase in blood pressure and pressure in the abdomen. This therefore may temporarily decrease blood flow to the baby [2].
Contracting the pelvic floor muscles before and during heavy lifting can help counteract the impact of increased intraabdominal pressure on the pelvic floor and baby [51].
Frequency and Duration of Exercise
Most guidelines recommend pregnant individuals complete at least 30 minutes of exercise at latest 5-7 days/week [13,77-81]. Individuals without previous regular exercise should gradually increase duration of exercise. One can begin with as little as 10 minutes.
Is There a Maximum Amount of Exercise?
There is limited data available on the maximum amount of safe exercise in pregnancy. For those who want to engage in prolonged exercise (>45 min), consider doing so in air conditioning and pay attention to hydration and overheating.
Intensity of Exercise
Exercise prescriptions are usually tailored to one’s level of physical ability. Some guidelines suggest that for previously sedentary individuals, start with low- to moderate-intensity exercise (casual to brisk walk and low-intensity workouts), increasing the intensity gradually.
For those who were regular exercisers before pregnancy and who have uncomplicated, healthy pregnancies, guidelines suggests that high-intensity exercise programs (eg, jogging, aerobics) can be done with no adverse effects [2,3,81], as long as one avoids the risks discussed above, such as overheating and excessive loads.
How Does Pregnancy Affect Exercise Capacity?
It is usually expected that fitness levels will decline somewhat as pregnancy progresses [13,79]. However, some individuals may improve their fitness levels with [15,82], with medical guidance and clearance.
Gauging Exercise Intensity
For moderate exercise, it should feel somewhat hard. A good way to gauge this is through the "talk test”. This test means that you should be able to carry on a normal conversation with moderate exercise intensity. In comparison, vigorous exercise makes it difficult to carry on a normal conversation easily.
Hydration
Dehydration is a potential risk with long intense exercise in warm environments. This can be reduced with hydration before, during, and after exercise.
When to stop exercising
Pregnant individual should stop exercising promptly and call their health care provider if they have any of the following warning signs of a potential problem [3,90]:
Vaginal bleeding
Abdominal pain with or without nausea
Regular painful contractions
Amniotic fluid leakage
New shortness of breath before exertion
Dizziness or fainting episode
Headache
Chest pain
Muscle weakness affecting balance
Calf pain or swelling
Conclusion
Exercise during pregnancy is a highly beneficial practice for most individuals, promoting general health and enhancing pregnancy outcomes. Engaging in regular, moderate-intensity physical activity—tailored to each person's unique health and fitness level—can lead to improved cardiovascular health, weight management, and reduced risks of pregnancy complications like gestational diabetes, preeclampsia, and C-sections. However, it is crucial to be mindful of potential risks and contraindications. Consulting with a healthcare professional before starting or modifying an exercise routine is essential to ensure the safety and well-being of both the pregnant individual and the baby. By incorporating safe, low-impact exercises and staying mindful of one’s body, most pregnant individuals can enjoy the numerous benefits of physical activity throughout pregnancy.
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