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Exercise and pregnancy |
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effect on uterine activity. Runners often complain of contractions
during exercise. The cited study did not find any evidence of an
increase in preterm labor, premature rupture of the membranes or fetal
distress (11). Musculoskeletal Changes Pregnancy leads to some obvious alterations of the woman's body. These changes often make exercise and other activities requiring balance more difficult. Changes include enlarging breasts, uterus, and fetus, an increase in lumbar lordosis and anterior tilt to the pelvis. In addition, weight-bearing exercise becomes a greater concern. Sudden movements may exacerbate these mechanical difficulties and increase the potential for injury. Increases in joint laxity may lead to a higher risk of strains or sprains. Contraindications to Exercise Contraindications to exercise during pregnancy, as listed in the most recent ACOG technical bulletin, are given in the table below (1). Contraindications Pregnancy-induced hypertension Preterm rupture of membranes Preterm labor during the previous or current pregnancy or both Incompetent cervix or cerclage placement Persistent second- or third-trimester bleeding Placenta previa Intrauterine growth retardation Relative contraindications Chronic hypertension Thyroid function abnormality Cardiac disease Vascular disease Pulmonary disease |
Benefits of Exercise to Pregnancy and Labor In a study comparing degree of physical conditioning and obstetrical outcome, the well-conditioned subjects were found to have shorter labor, less need for obstetrical intervention and fewer signs of fetal compromise (12). Exercise may also have a favorable effect on the subjective experience of discomfort during pregnancy. In a study tracking exercise throughout pregnancy (13), women who exercised in the three months before pregnancy felt better during the first trimester than those who did not exercise. Exercise in the first and second trimesters was correlated with feeling better in the third trimester. Another study of maternal exercise (14) showed a decrease in perceived exertion during labor. No difference was found in gestational length, maternal weight or duration of the first stage of labor (14,15). Recommendations for Exercise Prescription A controlled analysis of exercise prescription is lacking, because studies in humans are limited. Any exercise regimen should be individually structured to the patient; her goals, physical conditioning and general health should be considered. The physician should offer an explanation of the theoretic causes of concern, balanced with a reminder that clinical studies to date have shown no adverse effects from moderate exercise (15,22). The intensity, duration and frequency of exercise should start at a level that does not result in pain, shortness of breath or excessive fatigue. Regular exercise at least three times per week for at least thirty minutes per outing is preferable to intermittent activity. Exercise may then progress at a rate that avoids significant discomfort or exhaustion. Patients should be counseled to perform frequent self-assessments of physical conditioning and well-being, including hydration, caloric intake, quality of rest and presence of muscle or joint pain. It should be stressed that decreases in exercise performance are common, especially later in pregnancy. The goal is to allow the pregnant patient to obtain the maximal benefits derived from exercise, while ensuring that no detrimental effects occur in the mother or the fetus (1,15-17,22). The patient can minimize thermal stress by performing exercise in the early morning or late evening to improve heat dissipation when it is hot outside. Fans may be used during stationary cycling or other indoor exercise, and swimming is the best option. It is prudent to avoid exercise when the weather is very hot or humid, since heat dissipation is impaired at these times. Wearing appropriate loose clothing that allows adequate ventilation is also advisable (1,15,16,18). |
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