Exercise During Pregnancy

Introduction

Modern medical studies have challenged a variety of myths about pregnancy and exercise. Previously, it was wrongly thought that prenatal exercise may cause miscarriage, fetal overheating in the womb, placental abruption, stillbirth, and low birth weight. For these and other reasons, pregnant women were told that they should only exercise for fifteen minutes at a time and limit heart rate levels to 140 beats per minute.

Benefits for Mom

Prenatal exercise benefits women in five particular areas: the heart and circulatory system, lung and placental gas support, body temperature and sweating, metabolic and hormonal responses, and muscle, ligament and bone adaptations. Blood volume, plasma volume and red cell volumes of exercising pregnant women are 10 to 15 percent higher than women who do not exercise. Body tissues are more able to take up and use oxygen. Pregnant, exercising women have increased abilities to deal with heat stress, since they are more able to eliminate excess heat. Pregnancy and exercise combined provide higher amounts of glucose and oxygen for the baby. Finally, prenatal exercise may reduce laxity of ligaments and improve overall muscle strength and tone.

Benefits for Baby

Whether a woman begins regular exercise after pregnancy or continues from before conception, exercise has not been shown to contribute to an increased chance of premature birth. In fact, recent studies indicate that prenatal exercise actually makes babies more capable to deal with the stresses of labor and delivery. Babies whose mothers exercise during pregnancy may also have decreased chances of becoming obese later in life. Frequent, intense exercise contributes to reduced body-fat content, which may cause lower birth weights. Most babies’ body-fat levels are about 14 percent, whereas those with exercising moms usually have a 9 percent body-fat level.

Maternal Weight Loss

If you’re like many moms, you might be concerned about post-natal weight loss. Out of the 24- to 28-pounds that women normally gain during pregnancy, a portion goes to the baby: six to nine pounds to the fetus, one to two to the placenta, and two to amniotic fluid. The remaining weight goes to the mother: four to six pounds of protein stores, two to three pounds of fluid, two pounds to the enlarged uterus, one to two pounds to the breasts, and three to four pounds to overall increased blood volume. Exercising during your pregnancy gives you a head start to losing your baby fat, since women who continue exercise throughout pregnancy deposit less fat than those who do not.

Conclusion

If your doctor gives you the green light, you can and should continue exercise during your pregnancy. However, consult your doctor if you have any complications. The American College of Obstetricians and Gynecologists recommends that women who have pre-existing cardiac, vascular, pulmonary or thyroid diseases discontinue exercise during pregnancy. Women who have had three or more miscarriages should discontinue exercise until the second trimester. Women who experience regular bleeding during the second and third trimesters, whose water has broken, or whose babies are in a breech position in the third trimester should also discontinue exercise. Some other health conditions, such as as diabetes, obesity, hypertension, anemia or back, joint and muscle problems, may also exclude exercise from a woman’s pregnancy. Placental disorders, such as placenta previa or placental abruption, are other reasons to discontinue exercise.If you have any concerns, discuss prenatal exercise with your doctor before starting a regular program.