Pre and Post Natal
Pregnancy stresses the body more than any other physiological event in a healthy woman’s life (9). A variety of cardiovascular, metabolic, hormonal, respiratory, and musculoskeletal adaptations take place during the 9 months of pregnancy. Can regular, moderate physical activity provide benefits to the mother and fetus? On the other hand, could high volumes of intensive exercise pose potential risks for pregnancy outcome?
Moderate amounts of exercise during pregnancy are recommended for the health and fitness of the mother and baby (8, 11).Exercise training during pregnancy is a common practice. Scientific evidence suggests that physical activity of moderate intensity improves maternal and fetal well-being. Women who continue to exercise during pregnancy usually experience the following (5, 6):
- Improved cardiovascular function
- Limited weight gain and body fat retention
- Improved digestion
- Reduced constipation
- Reduced back pain
- Improved attitude and mental state
- Easier labor or reduction in possible complications during labor
- Reduced odds of cesarean delivery
- Faster recovery
- Better fitness level
Moreover, moderate exercise appears to reduce diastolic blood pressure in pregnant women at risk of hypertension (11). The offspring of exercising pregnant women may have a reduced fat cell growth rate without compromising other body cell growth, a high stress tolerance, and an advanced neurological developmental rate (4, 5).
The physiologic changes associated with pregnancy warrant evaluation of obstetric and medical risks prior to engaging in regular physical exercise.
Debate still centers on whether intense and prolonged exercise by the pregnant mother can cause harm to the growing fetus. Concerns regarding the possible adverse effects of high-intensity exercise participation have focused on: 1) inadequate availability of oxygen or substrate for mother and fetus, 2) hypothermia-induced fetal distress or birth abnormalities, and/or 3) increased uterine contractions. However, current studies indicate that healthy women with uncomplicated pregnancy do not need to limit their exercise for fear of adverse effects (3). Generally, participation in a wide range of recreational activities appears safe during and after pregnancy. Women should be encouraged to engage in a consistent, moderate-intensity physical activity to reap the health-related benefits associated with exercise. Overly vigorous activity in the third trimester, activities that have a high potential for contact, or activities with a high risk of falling should be avoided. In addition, during pregnancy refrain from activities with a risk of abdominal trauma, exertion at altitude greater than 6,000 feet, and scuba diving (3).
One large-scale study of some 2000 women in Missouri showed that those who largely avoided exercise during pregnancy were more likely to give birth to very low birth weight infants (who are more prone to sickness and death) (7). In another study of some 400 pregnant women, aerobic exercise throughout pregnancy led to fewer discomforts later on (10).A few studies even suggest that fit mothers experience shorter labor (9). In general, 30-45 minutes of moderate aerobic activity on a near-daily basis does not appear to expose the mother to serious metabolic consequences that might adversely affect her or the fetus.
In 1994, the American College of Obstetricians and Gynecologists (ACOG) released their new guidelines. According to the ACOG, “There are no data in humans to indicate that pregnant women should limit exercise intensity and lower target heart rates because of potential adverse effects”. However, the ACOG did urge that regular, moderate exercise is sufficient to derive health benefits, and that pregnant women should listen to their bodies, stop exercising when fatigued, and not exercise to exhaustion (2).
In general, it appears that trained women, who were exercising regularly prior to conception, may continue their exercise program, although often specific symptoms and overall comfort level lead to changes in mode of exercise and decreases in duration, frequency, or intensity (8, 9). For women who were not exercising regularly before pregnancy, it is safe to begin a moderate exercise program, particularly in the second trimester (9). Maintenance of regular physical activity during pregnancy helps keep the mother fit and healthy, causes no harm to the growing fetus, and may improve the birthing experience.
Although it appears that there are compensatory mechanisms that serve to protect the fetus for all of the potential physiological problems imposed by intensive exercise during pregnancy, atypical and high volumes of intensive exercise should be avoided until more is known about the health effects to both the pregnant mother and the fetus.
Learn how an Accredited Exercise Physiologist can help you to begin and maintain exercise in your life, so you can enjoy the health benefits of Exercise during and after pregnancy:
What Does an Exercise Physiologist Do?