Can Exercise Cause Miscarriage?

Miscarriages are usually no one’s fault. Sometimes people worry that exercising in early pregnancy increases the risk of miscarriage, but this is very unlikely. In fact, doctors encourage most women to exercise throughout pregnancy and after they give birth.

One research analysis that reviewed over 100 other studies on physical activity and pregnancy found less than 1% of "adverse events" were related to exercise, and these adverse events were uterine contractions—not miscarriages or other pregnancy complications. This review, published in 2017, concluded that even vigorous activity could not be tied to miscarriage risk.

Another more recent research review published in 2019 came to a similar conclusion. After analyzing 23 studies of miscarriage, this review noted that "prenatal exercise is not associated with increased odds of miscarriage."

Causes of Miscarriage

If you have had a pregnancy loss, it is natural to speculate about whether something that you did might have caused it. But the majority of early pregnancy losses (50% or more) result from chromosomal abnormalities. Exercise does not change a baby’s chromosomal makeup.

Other risk factors include medical conditions such as obesity, sexually transmitted infections (STIs), poorly controlled diabetes or thyroid disease, or uterine malformations and lifestyle factors such as smoking or drinking alcohol. Again, exercise will not change or worsen these risk factors.

It is unlikely that exercise is a factor in the great majority of miscarriages, but it may be a concern for women with certain medical conditions. Talk to your doctor about whether you should make modifications to your exercise regimen.

How to Exercise Safely During Pregnancy

The ACOG's stance is that exercise in pregnancy has few risks and has been shown to benefit most women. However, you may need to modify some exercise routines because of the way your body changes during pregnancy.

When you're pregnant, the ligaments that support your joints relax, which increases your risk of injury. Plus, your center of gravity shifts as your body grows, which can put more pressure on your pelvis and lower back and cause you to lose your balance more easily as you get later into pregnancy.

Consider Your Fitness Level

If you worked out regularly before you were pregnant, then your doctor is likely to encourage you to keep up with your usual program. If you're just starting an exercise routine, on the other hand, your doctor may recommend doing so gradually.

Go Low-Impact

Again, if you have an established running routine, stick with it (with your doctor's OK). If not, try brisk walking or swimming; both are easy on the body but still good cardiovascular workouts. Many yoga poses are also safe during pregnancy (some studios even offer prenatal yoga classes), but avoid doing any exercises that keep you lying flat on your back in the second and third trimesters.

Reduce the Risk of Falls

Falling in the first trimester is very unlikely to cause a miscarriage. But later in pregnancy, a hard fall could cause a placental abruption, which is dangerous to your baby. This is why doctors recommend avoiding activities like horseback riding, mountain biking, and downhill skiing.

Avoid Overheating

Elevated body temperature can cause pregnancy complications, but doctors say that exercise won't cause body temperature to rise high enough to be of concern. Still, avoid hot tubs and saunas, and try to work out in an air-conditioned space if it is hot outside.

Stay Hydrated

Your body needs more fluids during pregnancy, so be sure to replace what you are losing in sweat. Drink plenty of water before, during, and after exercise.

A Word From Verywell

Exercising during pregnancy, even in the first trimester, is not associated with miscarriage. In fact, exercise is beneficial for the great majority of pregnant people. If you have any concerns about whether exercise is right for you, talk with your healthcare provider. They can offer personalized advice about exercise and wellness during your pregnancy.