2. Table of contents
Physiologic changes in pregnancy
Type, intensity, and frequency of exercise
Benefit of exercise in pregnancy
Contraindications of exercise in pregnancy
Warning signs to terminate exercise while pregnant
Maternal advice after exercise recommendation
Exercise in postpartum
4. Nutritional requirement
After the 13th weeks of pregnancy, about 300kcal per day
are required to meet the metabolic needs of pregnancy
This energy requirement is increased through exercise.
In weight bearing exercise, such as walking, the energy
requirement progressively increases with the increase in
weight during the course of the pregnancy.
A related consideration to nutrition and exercise during
pregnancy is adequate carbohydrate intake.
Artal et al, 2003
5. Cardiovascular changes
Pregnancy induces
– increase in maternal blood volume, cardiac output, and
resting pulse
– decrease in maternal systemic vascular resistance.
– Hemodynamics depends on position
– Cardiac output in third-trimester pregnancy is maximal
– in the left or right lateral recumbent position.
– Decreased cardiac output
– Supine position
– Motionless standing
Clark et al, 1991
Jovanovic-Peterson et al, 1989
6. Respiratory changes
During pregnancy minute ventilation increases by almost
50%, largely as a result of increased tidal volume.
– increase in arterial oxygen tension to 106-108 mmHg in the first trimester,
decreasing to a mean of 101-106 mmHg by the third trimester.
– increase in oxygen uptake, and a 10-20% increase in baseline O2 consumption.
– Because of the increased resting oxygen requirements and the increased work of
breathing brought about by physical effects of the enlarged uterus on the
diaphragm, there is decreased oxygen available for the performance of aerobic
exercise during pregnancy.
– in some fit women, there do not appear to be associated changes in maximum
aerobic power or acid-base balance during exercise in pregnancy when
compared with the nonpregnant state
Artal et al. 1986, Prowse et al.1965
Templeton et al,1976
7. Mechanical changes
The enlargement of uterus and breasts that occurs
during normal pregnancy results in a shift in the
physical center of gravity in the pregnant woman.
– loss of balance may prove dangerous
Hormonal influences may result in generalized
increases in joint laxity, predisposing the pregnant
woman to mechanical trauma or sprains.
Calguneri et al. 1982, Artal etal.1991
8. Thermoregulatory changes
Both basal metabolic rate and heat production
increase during pregnancy
Teratogenecity
– 39.2°C, with hot tub use in early pregnancy
– an increase in maternal core body temperature during
embryogenesis exceeding 1.5°C has been observed to cause
cessation of neuronal mitotic cell growth in the ependymal
layer of the developing brain.
– Nonpregnant women exercising at 70% of maximal effort on
a treadmill for 20 minutes, the core body temperature rose
by an average of 1.5°C.
– Fit individuals are known to thermoregulate their core
temperature more efficiently.
Hytten et al.1980, Artal et al.1991, Edwards et al.1986, Milunsky et al.1992
9. 2002 ACOG recommendation
Exercise in pregnancy
In the absence of either medical or obstetric
complications during pregnancy
women should perform 30 minutes or more of
moderate-intensity exercise on most, if not all,
days of the weeks.
Moderate exercise
– Defined as activity for 30 or more minutes a day, 5 or more
days a week
– ex. : Brisk walking, bicycling, vacuuming, gardening, or any activity
that causes small increases in breathing or heart rate
ACOG, 2002
Centers for Disease Control, US physical activity statistics: definitions. 2006
10. Type of exercise
Safe Avoid
Aerobic exercise
Progressive resistive strengthening
Stretching exercises
Yoga
Stationary bicycling
Jogging
Walking
Stair climbing
Treadmill use
Water exercise
Swimming
Supine position after the first
trimester
Motionless standing
Recreational sports with a high
potential for contact, such as ice
hockey and baseball
Increased risk of falling, such as
horseback riding and gymnastics
Advised not to scuba dive because
the fetus is at risk of decompression
sickness
Artal et al. 1991, Clark et al.1991, Camporesi et al. 1996 , ACOG 2002
11. Intensity of exercise
ACSM(American college of sports medicine) recommend that
intensity should be 60-90% of maximal heart rate or 50-85% of
either maximal oxygen uptake or heart rate reserve.
60 % of maximal heart rate or 50% of maximal oxygen uptake
– for most pregnant women who did not engage in regular exercise
before pregnancy
70% of maximal heart rate or 60% of maximal oxygen uptake
– for those who wish to continue to maintain fitness during pregnancy.
Artal et al, 2003
13. Frequency of exercise and rate of progression
Previously sedentary women
– Start with 15 min of exercise three times a week
– Gradually increase to 30 min four times a weeks at low to
moderate intensity
Active women
– Keep their routine exercise or perform at least moderate- to-
vigorous exercise
– Four times a week in sessions of 30min or more
Atheletes or women who have higher fitness status
– Evaluated individually
– The intensity of exercise like running should be reduced
Davies et al, 2003
14. Benefits of exercise and activity during pregnancy
Decreased chance of preeclampsia, second leading
cause of maternal death
Decreased chance of operative delivery
Decreased chance of developing gestational diabetes
Improved mood
Reduction of pregnancy discomforts- backache and
lower extremity edema
Possible prevention of type II diabetes
Possible prevention of chronic hypertension
ACOG, 2002
21. Gestational diabetes mellitus
Epidemiologic data suggest that exercise may be
beneficial in the primary prevention of gestational
diabetes, particularly in morbidly obese women (BMI >33)
The American Diabetes Association has endorsed exercise
as “a helpful adjunctive therapy” for gestational diabetes
mellitus when euglycemia is not achieved by diet alone
Vigorous activity : RR, 0.77 (95% CI, 0.69-0.94).
Brisk walking pace : RR, 0.66 (95% CI, 0.46-0.95)
compared with an easy pace.
Dye et al, 1997
Jovanovic-Peterson et al 1996, Bung et al.,1996
Zhang et al, 2006
22. ACOG contraindications to exercise in pregnancy
Hemodynamically significant heart disease
Restrictive lung disease
Incomplete cervix/cerclarge
Multiple gestation at risk for premature labor
Persistent second- or third trimester bleeding
Placenta previa after 26weeks of gestation
Premature labor during current pregnancy
Ruptured membranes
Preeclampsia
ACOG,2002
23. ACOG relative contraindications to aerobic
exercise during pregnancy
Severe anemia
Unevaluated maternal cardiac arrhythmia
Chronic bronchitis
Poorly controlled type 1 diabetes
Extreme morbid obesity
Extreme underweight (BMI < 12)
History of extremely sedentary lifestyle
IUGR in current pregnancy
Poorly controlled hypertension
Orthopedic limitations
Poorly controlled seizure disorder
Poorly controlled hyperthyroidism
Heavy smoker
ACOG,2002
24. Warning signs to terminate exercise while pregnancy
Vaginal bleeding
Dyspnea prior to exertion
Dizziness
Headache
Chest pain
Muscle weakness
Calf pain or swelling (need to rule out thrombophlebitis)
Preterm labor
Decreasing fetal movement
Amniotic fluid leakage
ACOG,2002
25. Maternal advice after exercise
recommendation
Should aware of uterine contractions
Less than the fetal movements in 12 hours is an
indication that further investigation at a hospital
is warranted
No longer suggest the routine counting of fetal
movements in the second half of a woman’s
pregnancy
NICE Guideline, 2004
26. Exercise in postpartum
Many of the physiologic and morphologic changes of
pregnancy persist 4-6 weeks postpartum.
Thus, prepregnancy exercise routines should be resumed
gradually based on a woman’s physical capability.
No known maternal complications are associated with
resumption
Decreased incidence of postpartum depression and
stress relieving
Hale et al, 1996
Koltyn et al, 1997
ACOG, 1994; ACOG 2002
