Page 139 - Athletic Health Handbook
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increase. In well-conditioned athletes, and uterus. This results in spinal lordo- may result from a combination of
blood volume increases are greater sis which pregnant women compensate early delivery (one week earlier than
than in sedentary women.17 Blood for by abducting the shoulders and sedentary women) and decreased
pressure falls slightly, reaches a nadir flexing the cervical spine. Proges- brown fat.7,10 However, brown fat
in the second trimester, and rises to terone and relaxin increase pelvic and is important for energy and heat
prepregnancy levels by term. joint laxity during pregnancy. Due to regulation in infants, especially in
all the musculoskeletal changes during premature infants; thus, decreased fat
Respiratory System: The anatomy pregnancy, pregnant women theoret- deposition may have adverse conse-
of the chest wall changes in pregnancy, ically have a greater propensity for quences in the preterm infant. Babies
allowing for increased oxygen trans- falling and for excess torque forces born to exercising mothers tolerate
port and utilization. The ribcage has on lax joints which may predispose labor well and show less behavioral
increased elasticity, flaring, and expan- them to more sprains.14 or biochemical evidence of undue
sion, and the diaphragm elevates. stress in late pregnancy and labor.12
Tidal volume, minute ventilation, Maternal Effects of Exercise When compared to age-matched
and oxygen consumption all increase controls, offspring of exercising
during pregnancy. The respiratory Regular exercise enhances placental mothers have slightly better motor
changes of pregnancy facilitate gas growth and the normal physiologic skills at one year of age and are much
exchange between the mother and the changes of pregnancy. Potential leaner with better performance on
fetus through the placenta. Changes maternal benefits of exercise during intelligence testing at 5 years old.10,11
in maternal oxygenation are amplified pregnancy include maintenance of
in the fetus. Therefore, prolonged musculoskeletal and cardiovascular Acute Maternal-Fetal Effects
anaerobic exercise should be avoided fitness, avoidance of excessive weight During Exercise
to prevent maternal acidosis and gain, and decreased musculoskeletal
hypoxia which will induce fetal acido- complaints such as back pain. Women Acutely, exercise has relatively little
sis and hypoxia. However, aerobic who exercise during pregnancy tend effect on the fetus or uterus when the
exercise in pregnant women causes to have increased energy, improved mother and fetus are healthy. Theo-
greater increases in minute ventilation moods, and better quality sleep. retical concerns regarding increased
than in nonpregnant women and this Additionally, exercise may be benefi- core temperature during pregnancy
hyperventilation can protect against cial in the primary prevention of have not been found to be significant
harmful shifts in blood oxygenation gestational diabetes, especially in because core temperature in exercising
or pH.17 morbidly obese women (BMI >33).16 pregnant women did not reach
potentially teratogenic levels (terato-
Musculoskeletal System: Changes Fetal Effects of Exercise genic potential at 102.5 degrees).1
in posture, gait, balance, and joint Also, physiologic changes during
laxity occur due to the physical changes Potential effects of sustained weight- pregnancy, including lower resting
of pregnancy. The center of gravity bearing exercise on the fetus include temperature, sweating threshold,
moves forward and upward due to the reduced birth weight and decreased and decreased venous tone, facilitate
significant enlargement of the breasts labor stress. This reduced birth weight

Table 1: Warning Signs Table 2: Absolute Contraindications Table 3: Relative Contraindica-
to Terminate Exercise to Aerobic Exercise While Pregnant2 tions to Aerobic Exercise While
While Pregnant2 Pregnant2
Hemodynamically significant heart disease
Vaginal bleeding Restrictive lung disease Severe anemia
Dyspnea prior to exertion Incompetent cervix/cerclage Unevaluated maternal cardiac
Dizziness Multiple gestation at risk for arrhythmia
Headache premature labor Chronic bronchitis
Chest pain Persistent second- or third-trimester Poorly controlled type I diabetes
Muscle weakness bleeding Extreme morbid obesity
Calf pain or swelling Placenta previa after 26 weeks Extreme underweight (BMI <12)
Pre-term labor of gestation History of extremely
Decreased fetal movement Premature labor during the sedentary lifestyle
Amniotic fluid leakage current pregnancy Orthopedic limitations
Ruptured membranes Poorly controlled seizure disorder
Preeclampsia/pregnancy-induced Poorly controlled hyperthyroidism
hypertension Heavy smoker

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