Is it Safe to Exercise During Pregnancy?

By Dr. Liji Thomas, MDReviewed by Dr. Mary Cooke, Ph.D.

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• The benefits of exercise during pregnancy
• Current advice
• What exercises should I do during pregnancy?
• How to exercise safely in pregnancy
• Red flags for exercise in pregnancy
• When to avoid exercise
• Pelvic floor and core exercises

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The benefits of exercise during pregnancy

Exercise is often viewed with a doubtful eye during pregnancy, but all the data available so far shows that it has a beneficial effect on a woman with a low-risk pregnancy.

This includes:

General health benefits like

• maintaining a healthy body shape
• regulating weight gain
• improving mental health by boosting a sense of well-being
• better sleep and stress relief
• preventing tiredness

Benefits related to the demands of pregnancy:

• preventing and managing constipation
• relieving back and pelvic pain
• preventing varicose veins
• improving circulatory health
• preparing the body for the immense demands of labor and reducing the risk of long labors and instrumental delivery such as with the help of forceps or vacuum
• reduced risk of preterm delivery
• reducing the risk of gestational diabetes, hypertension and of excessively large fetuses, and of childhood obesity in the offspring
• reducing the chances of emergency Cesarean section

Current advice

Despite these proven benefits, most antenatal patients are not routinely instructed to exercise if they are sedentary, and those who exercise are not encouraged to maintain their routines. The current recommendation by the American College of Obstetricians and Gynecologists (ACOG) dating from 2015 is for 150 or more minutes of moderate exercise a week, or 20-30 minutes a day. However, not more than 15%, and perhaps as few as 5%, actually follow this advice. Inactive women are not encouraged to add exercise into their routine, while over 50% of pre-pregnancy exercisers stop at this time.

Any exercise is better than none, so even in those days when pregnancy feels like a miserable condition, the woman should be encouraged to exercise for a few minutes. Most women do drop a lot of their training time, particularly in the first trimester, but many active women pick it up in the second and third trimesters. However, each woman is different and should be free to do it the way she feels best, provided it is safe.

What exercises should I do during pregnancy?

Pregnancy allows a large range of exercise, including brisk walks, swims, water aerobics, pilates, yoga, and strength building (as long as the weights aren't too heavy). Running and jogging is fine for those who have already been doing so before they became pregnant. However, later in pregnancy, running may become uncomfortable and may be replaced with brisk walks. As the joints loosen during later pregnancy, high-impact exercises and those which put a strain on the joints should probably be avoided. These include aerobics, jogging on roads, and advanced yoga positions. It is easier to lose balance during pregnancy, so exacting sports that depend on balance should be avoided.

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How to exercise safely in pregnancy

Exercise-associated risks to watch for include:

• Avoid heating up too much during exercise
• Exercise intensity which leaves the woman breathless
• Keep hydrated and feed yourself regularly to avoid steep drops in blood sugar
• Avoid contact sports, those which involve a high chance of falling, and others which involve steep pressure drops and abrupt movements including scuba diving and skydiving
• Avoid exercises that involve lying on the back because these can interrupt the blood supply to the baby as well as to the brain of the pregnant woman, causing a feeling of faintness
• Avoid exercises which require contraction of the abdominal muscles, because they put undue stress on the uterus

Reasons for not exercising in pregnancy
In pregnancy, people worry about how exercise will affect the fetus concerning

• Increased risk of miscarriage
• Fetal hypoxia
• Fetal bradycardia
• Premature labor
• Low birth weight

However, miscarriage is only a risk if severe exercise is undertaken during implantation. A study based on only six high-class athletes showed that when exercising to achieve 90% or more of the maximal heart rate, fetal bradycardia appeared though it was quickly relieved. This has led to the advice to avoid frequent high-intensity exercise.

Red flags for exercise in pregnancy

The ACOG has outlined certain signs that signal an immediate halt to exercise in pregnancy. These include:

• Any vaginal bleeding (could be a sign of threatened miscarriage or preterm labor)
• Dizziness, chest pain, palpitations, headache
• Muscle weakness or difficulty in walking
• Calf muscle pain or swelling (could be a clot in the deep veins)
• Preterm labor
• Reduced fetal movements
• Escape of amniotic fluid before labor begins

When to avoid exercise

Some pregnancy conditions preclude any exercise:

• Abnormal shortening of the cervix which predicts preterm labor
• Placenta previa or low-lying placenta even after week 26
• Persistent vaginal bleeding
• Restrictive lung disease
• Breathlessness before beginning exercise
• High blood pressure

Pelvic floor and core exercises

Pelvic floor exercises are recommended throughout pregnancy and following childbirth because of the crucial role of the pelvic muscles in labor and in supporting the abdominal and pelvic organs in daily life. In pregnancy, the increased volume and weight of the abdominal contents puts additional strain on the pelvic floor muscles. This may cause immediate incontinence, and sagging of the bladder and uterus in later life.

Pelvic floor exercises can help prevent this problem. These consist of selectively tightening the muscles that are used to stop the flow of urine, but at times when the woman is not passing urine. It should be done in sets of ten, around five times a day, with each contraction being held for about 5 seconds.

Core stability exercises are also very helpful in boosting abdominal muscle strength. One is to draw the abdominal wall inward and breathe out, holding to a count of 10, before relaxing and breathing in. This may be done in sets of 10 as many times as possible, in the sitting, standing, or hands-and-knees position.