What Does Too Much Exercise Cause When You're Pregnant?

Exercise during pregnancy can be a benefit in a number of ways. A regular workout schedule helps you sleep better, increases your circulation and, according to the American Pregnancy Association, can lead to a shorter labor for some lucky women. Too much exercise, on the other hand, can sometimes cause complications for mother and baby. Talk to your doctor for specific exercise recommendations based on your individual health during pregnancy.

Overheating

• A physical workout raises your body temperature. Exercising too much without drinking enough water can cause dehydration, which can cause lightheadedness and fatigue in the average person. When you are pregnant, however, overheating can be a real concern for the health of the fetus. "The Journal of Perinatal Education" reports that continued exposure to temperatures of 102 to 104 degrees Fahrenheit can cause neural tube and other birth defects, especially in the first trimester. Build rest time into your workouts, hydrate with plenty of water and avoid exhausting yourself during exercise. The APA states that if you are out of breath during a workout, you're working too hard.

Restricted Nutrients

• During physical activity, your circulation increases to deliver more oxygen to your heart, lungs and muscles. If you exercise too hard, blood flow to your uterus can decrease, leaving your unborn child with less oxygen and nutrients. Restricted nutrients can lead to low birth weight in some babies. Keep your heart rate in the 60 to 70 percent of the maximum target range to prevent your workout from being too strenuous, according to What To Expect. Subtract your age from 220 and divide the result by 0.60 to get your 60 percent target heart rate.

Contractions

• Too much exercise can cause contractions and uterine irritability in pregnant women for a variety of reasons, including dehydration and hormonal surges. Women who routinely exercise may not be affected as much by hormonal fluctuations as those who have just started to work out, according to "The Journal of Perinatal Education." Contractions related to dehydration usually go away once you drink water. However, in some women exercise-induced contractions can lead to preterm labor.

Fetal Trauma

• The stress and strain that excess exercise puts on your body can cause trauma to the support structures of the uterus and may even cause fetal trauma in some cases. Bleeding and preterm contractions can occur in some people, according to KidsHealth. Avoid high-impact exercises such as contact sports, anything that involves jumping or bouncing and weight lifting. Instead, choose low-impact options such as walking, swimming or yoga.