Exercise In Pregnancy1

1. Exercise in Pregnancy
Jennifer Hale, M.D.
Valley Baptist Family Practice Residency

2. Objectives
•Discuss risks and benefits of exercise for both mother
and baby
•Describe physiologic adaptations to exercise during
pregnancy
•Review absolute and relative contraindications to
exercise during pregnancy
•Prescribe an individualized exercise program for a
pregnant athlete
•Practice what we preach !

3. “We are all athletes…some of us are in
training, and some of us are not”

5. Historical Perspective
“The midwives answered Pharaoh, ‘Hebrew
women are not like Egyptian women; they are
vigorous and give birth before the midwives
arrive.’”
Exodus 1:19

6. Fun Facts
•↑ HDL, ↓ triglycerides
•↓ blood pressure
•Improved endothelial
function
•Improved glycemic
control
•↓ risk of CAD
•↑ longevity
•↓ cancer risk
•↓ proinflammatory
cytokines
•↓ oxidative stress
•Improved psychological
well-being

7. Continued…
•↑ energy
•↓ weight gain
•↑ strength/endurance
•↓ back pain
•Improved sleep
•Improved sense of
well-being
•↓ risk GDM
•↓ risk pre-eclampsia

8. Continued…
CDC and ACSM Recommendations:
•30-60min moderate-intensity physical activity “on
most—preferably all—days of the week”
•At least 60min to prevent weight gain, increase
fitness, achieve full health benefits

9. (Not So) Fun Facts
•Less than 25% pregnant women exercise
regularly
•40-60% are completely inactive during pregnancy
•Pregnancy seen as “confinement”
•Non-white women 50% less likely to exercise
•Rest/relaxation seen as more important
•Most women decrease or stop all exercise while
pregnant

10. ACOG Guidelines (1985)
•Overly conservative
•HR <140bpm
•No exercise over moderate intensity
•No longer than 15min
•Avoid valsalva (weight lifting)
•No exercise in supine position after 1
st
trimester

11. Where We’ve Come From
Zahereiva et al.
•From 1952-1972
-27% female athletes competing consecutively gave
birth between Olympic games
-most report feeling ‘more fit’ after childbirth

“They became stronger, had greater stamina
and were more balanced in every way after
having a child.”

12. Physiologic Adaptations during
Pregnancy and Exercise
•Cardiovascular
•Pulmonary
•Thermoregulatory Control
•Musculoskeletal

13. Cardiovascular
Rest
•↑ plasma volume
•↑ baseline heart rate
•↑ cardiac output
•↑ stroke volume
•↓ systemic vascular
resistance
Exercise
•↓ BP
•↓ vagal tone as
pregnancy advances
•Blunted HR response
to exercise

14. Continued…
ACOG Recommendations:
•Avoid exercise in supine position after 1
st
trimester
•Avoid prolonged standing
•HR > 140 now allowed

15. Pulmonary
Rest
•↑ tidal volume
•↑ oxygen uptake
•↑ resting oxygen
requirements
•↑ work of breathing
Exercise
•↓ oxygen available for
exercise
•↓ maximum
performance
•SOB with less exertion

16. Continued…
ACOG Recommendations :
•No specific recommendation, except…
•Exercise intensity should be based on symptoms

17. Thermoregulatory Control
Rest
•↑ basal metabolic rate
•↑ heat production
•Fetal core body temp 1ºC
higher
•↑ blood supply to skin
•Lower sweating threshold
Exercise
•↑ temp related to exercise
intensity
•↑ conduction of heat to
periphery
•Moderate exercise ↑ core
temp 1.5° first 30min
•↑ teratogenic risk?

18. Continued…
•Clap et al.
- 10 recreational joggers
- core body temp measured during moderate
intensity exercise
- pre-pregnancy, 20 and 32wks
•Results:
- increase in core body temp, but less so in
pregnancy (1°C lower)
- due to decrease in sweating threshold, etc.
- thus NTD not likely in humans

19. Continued…
ACOG Recommendations :
•Avoid hot, humid conditions, high altitudes
•Wear appropriate clothing
•Stay hydrated!
•Innate physiologic protection against hyperthermia

20. Musculoskeletal
Rest
•Center of gravity up and
forward
•↑ back pain
•↑ joint laxity
•Weight gain
Exercise
•May negatively affect
balance
•↑ force across hips/knees
up to 100% in wt bearing
•↑ fall risk?
•↑ instability, risk for injury?

21. Continued…
ACOG Recommendations :
•No specific guidelines
•Adjust activity based on gestational age,
symptoms
•Stretching/strengthening exercises

22. Exercise and Gestational
Diabetes
•Improves glucose tolerance, blunts insulin
response
•# hrs spent in exercise – ↓ risk of GDM
- Case control: 155 pts w/ GDM vs. 386 controls
First 20 wks — 48% reduction GDM
Greatest when combined w/ exercise 1yr prior
- ≥ 4.2 hrs/wk mod intensity exercise – ↓ 76%
•May prevent initiation of insulin

23. Exercise and Pre-eclampsia
•Reduces risk (40%)
- inversely related to time/intensity
Sorensen et al.
201 pre-eclamptic vs. 383 controls
- “any regular physical activity” first 20 wks 35%
- light/mod vs. vigorous 24% vs. 54%
- brisk walking (≥ 3mi/hr) 30-33%
- vigorous exercise year prior 60%
- stair climbing (1-4 flights/d) 29%

24. Other Benefits
•No ↑ risk of miscarriage
•Possible ↓ risk preterm birth
•↓ risk of cesarean section ?
•Faster recovery post-partum
•Labor duration ?

25. Effects on Infant
•Placenta larger, greater surface area
•Does not change uterine/umbilical blood flow
•FHR – accelerations, mild decelerations, then baseline
•Lower birth weight if vigorous exercise 5-6x/wk
•Children lighter/leaner
•Score higher on intelligence & oral language tests

26. Current ACOG Guidelines
•Even more liberal than previous
•In absence of contraindications, pregnant
women can follow ACSM recommendations
•Avoid supine positions after 1
st
trimester
•No reports that hyperthermia during exercise
is teratogenic

28. Exercise Prescription
Where to Start:
- Gather information for History & Physical Exam
- Gestational age
- Goals
- Grade
- “F I T T”

29. “F I T T”
•Frequency-
“most days of the week”
•Intensity-
THR vs. Borg scale
•Type-
walking/biking/running/swimming
•Time-
30-90min/day

30. Borg Scale

31. “F I T T”
•Frequency-
“most days of the week”
•Intensity-
THR vs. Borg scale
•Type-
walking/biking/running/swimming
•Time-
30-90min/day

32. Sample
60-90min30-60min30minTime
Competitive
activities
Also run/jog
dance, tennis
Walk, bike, stair,
swim, aerobics
Type
75-85% MHR
RPE- hard
65-85% MHR
RPE- mod hard
to hard
65-75% MHR
RPE- mod hard
Intensity
4-6x/wk3-5x/wk≥ 3x/wkFrequency
EliteRecreationalSedentary

33. Continued…
•Stretching
- static, not ballistic
- hold for at least 1min
•Weight Lifting
- 10-15 repetitions
- low weight

34. Nutrition
Four F’s:
•Food↑ 150cal/day 1
st
- 2
nd
trimester
↑ 300cal/day 3
rd
trimester
•Fluids↑ 30ml/day
1 lb = 500cc
•Fe (Iron)
•Folate

35. Contraindications
Absolute
•PIH/Preeclampsia
•Ruptured membranes
•Incompetent cervix
•2
nd
or 3
rd
trimester bleeding
•Multiple gestation
•Placenta previa after 26wks
•Heart disease
•Restrictive Lung disease
•Premature labor
Relative
•IUGR
•Cardiac dysrhythmias
•Severe anemia
•Chronic bronchitis, heavy
smoker
•Poorly controlled DM, HTN,
seizure d/o, thyroid dz
•Extremes of weight
•Orthopedic limitations

36. Warning Signs
•Vaginal bleeding
•Dyspnea prior to exertion
•Dizziness or presyncopal symptoms
•Headache, muscle weakness
•Chest pain, calf pain or swelling
•Preterm labor, leakage of fluid
•Decreased fetal movement

37. Breastfeeding and Exercise
•Integral role in post-partum weight loss
•Does NOT reduce milk production
•Increased lactate levels in breast milk after
exercise
Breastfeed before exercise!

38. Return to Competition
•No specific recommendations
•Guided by symptoms, ability to get back
into training
•Husbands play a big role

39. Summary
•Pregnancy is a good time to establish healthy
lifestyle habits
•Those adopted during pregnancy could affect a
woman’s health for the rest of her life
•Be aware of contraindications/warning signs
•Almost all women can safely exercise (or begin an
exercise program) during pregnancy

40. QUESTIONS?

41. References
ACOG. Exercise during pregnancy and the postpartum period. Clin Obstet Gyn. 2003;46 (2): 496-499.
Anonymous. The benefits and risks of exercise during pregnancy. J Sci & Med in Sport. 2002; 5(1):11-19.
Brenner IK, Wolfe LA, Monga M, McGrath MJ. Physical conditioning effects on fetal heart rate responses to
graded maternal exercise. Med Sci Sports Exerc. 1999;31(6):792-799.
Bungum TJ, Peaslee DL, Jackson AW, Perez MA. Exercise during pregnancy and type of delivery in
nulliparae. J Obstet Gyn Neonatal Nurs. 2000; 29(3):258-264.
Ceysens G, Rouiller D, Boulvain M. Exercise for diabetic pregnant women. The Cochrane Database. 2006;
1.
Clapp JF> The changing thermal response to endurance exercise during pregnancy. Am J Obstet Gyn.
1991; 165(6):1684-1689.
Dempsey FC, Butler FL, Williams, FA. No need for a pregnant pause: Physical activity may reduce the
occurrence of GDM and Preeclampsia. ACSM 2005; 33(3):141-149.
Dempsey JC, Butler CL, Sorensen TK, Lee IM, et al. A case control study of maternal recreational physical
activity and risk of GDM. Diabetes Res Clin Pract. 2004;66(2):203-15.
Ertan A, et al. Doppler examinations of fetal and uteroplacental blood flow in AGA and IUGR fetuses before
and after maternal physical exercise with the bicycle ergometer. J Perinatal Med. 2004;32(3):260-265.
Evenson KR et al. Vigorous Leisure Activity and pregnancy outcome. Epid. 2002; 13(6):653-659.
Jackson MR, Gott P, Lye SJ, Ritchie JW, Clapp JF. The effects of maternal aerobic exercise on human
placental volumetric composition and surface areas. Placenta 1995; 16(2):179-91.
Kramer MS. Aerobic exercise for women during pregnancy. The Cochrane Database. 2002; 3.
Larsson L, Lindqvist PG. Low-impact exercise during pregnancy-a study of safety. Acta Obstet Gyn
Scandinavica. 2005; 84(1):34.
Leet T, Fick L. Effect of exercise on birth weight. Clin Obstet Gyn. 2003; 46(2):423-431.

42. Continued…
Magann ER, Evans SF, Weitz B, Newnham, J. Antepartum, intrapartum, and neonatal significance of
exercise on healthy low-risk pregnant working women. Am Coll Obstet and Gyn. 2002;
99(3):466-472.
Marcoux S, Brisson J, Fabia J. The effect of leisure time physical activity on the risk of preeclampsia
and gestational hypertension. J Epid Comm Hlth. 1989; 43(2):147-52.
O’Toole ML. Physiologic aspects of exercise in pregnancy. Clin Obstet Gyn 2003; 46(2):379-389.
Pivarnik JM, Perkins CD, Moyerrbrailean T. Athletes and Pregnancy. Clin Obstet Gyn 2003; 46
(2):456-466.
Poudevigne MS, O’connor PJ. A review of physical activity patterns in pregnant women and their
relationship to psychological health. Sports Med. 2006;36(1):19-38.
Sorensen TK, Williams MA, Lee IM, Dashow EE, Thompson ML. Recreational physical activity during
pregnancy and risk of preeclampsia. Hypertension 2003; 41(6):1273-1280.
Wolfe, Larry A, Davies, Gregory. Canadian Guidelines for Exercise in Pregnancy. Clin Obstet Gyn
2003; 46(2):496-499.