Exercise in Pregnancy and the Postpartum Period

Notes for Yale School of Nursing Midwifery Students

c. 2009 Ann Cowlin, MA, CSM, CCE

 

 

          It is now well accepted that regular, moderate to vigorous exercise in pregnancy is safe and beneficial for mother and fetus [1-4]. Providing there are no contraindicated underlying pathologies, such as deep vein thrombosis, incompetent cervix or placenta previa in the third trimester, an active lifestyle in pregnancy can have tremendous short and long term benefits for both mother and offspring. Recent findings indicate, however, that most pregnant women do not meet the minimum threshold for effective activity as recommended by ACOG [5]; that is, 30 minutes of moderate exercise most days of the week [1]. Further, levels of activity decrease during the course of pregnancy and – as we have known for some time – motherhood is the greatest barrier to regular exercise for women.

 

          During the decades of research into the effects of exercise in pregnancy we have found that women who participate in aerobic activities prior to pregnancy or starting in the first half of pregnancy develop placentas that are larger (within safe parameters) and have greater proliferation of chorionic villi than women who do not [6]. The advantage to the fetus is greater nutrient and oxygen transport surface. Additionally, these women have a dose-related risk reduction for preeclampsia of 25 – 75%, with greatest risk reduction for the most vigorous exercisers [7]. They also recover from labor more rapidly by metabolizing free radicals ten times faster than sedentary women. Offspring of women who participate in aerobic activities appear to fare well and possibly have physical and mental advantages over those whose mothers do not [8.9].

 

          More recently we have learned that the fetuses of pregnant women who participate in aerobics demonstrate a beneficial training effect, i.e., they exhibit lower resting pulses and greater variability than fetus’ of mothers who do not participate in aerobics [10]. Previously sedentary women benefit from aerobic conditioning, showing increases in maximal aerobic power and submaximal duration, and preservation of anaerobic working capacity in late gestation [11], all of which are valuable assets during the prolonged, low-intensity endurance test of the first stage of labor followed by the strength test of the second stage.  Also, women who participate in vigorous activities in pregnancy are more likely to be physically fit in midlife [12], providing long term health advantages. On the other hand, women with preeclampsia are at increased risk for cardiac events in midlife [13, 14].

 

          Strength training, while not extensively studied, also appears to be well-tolerated by pregnant women and their fetuses, providing they avoid the valsava maneuver, extreme muscle fatigue, or long stretches of time in positions that may lead to orthostatic hypotensive syndromes, such as the supine position after the fourth month, and standing for long periods or doing leg presses in the inclined (semi-recumbent) position in the last trimester. Overweight pregnant women with insulin-dependent diabetes who participate in strength training (weight lifting) reduce their need for insulin [15].

 

          There is a benefit to relaxation and mind/body techniques because the Relaxation Response [16] plays a role in the release of oxytocin in the early and active phases of the first stage of labor.  A regimen including these components, led by an instructor with well-honed teaching skills, helps achieve this response at an effective level.  The effect of prenatal yoga has been difficult to assess. Studies that show effects have been conducted in settings where yoga is embedded as a daily spiritual practice [17]. Because the asanas, or positions, are the starting point for most U.S. instructors – rather than the third step (after acceptance and transcendence) of traditional teaching – and these postures are not all vetted for pregnancy safety and/or are changed for comfort in pregnancy, there are profound questions about the quality and effect of a given prenatal yoga session. At present, the benefits women most often attribute to yoga type activities are related to relaxation and relief of some discomforts through stretching.

 

          From experience we know postpartum women report that their exercise group plays a significant role in their well-being. Sampselle, et al [18] found two markers of postpartum well-being were significantly improved in women who participated in self-reported vigorous physical activity by six weeks postpartum.  In the first marker, postpartum weight retention, women with higher levels of activity retained less weight than the inactive group.  In the second marker, Lederman’s postpartum maternal adaptation questionnaire, vigorous exercisers had better scores on all adaptation subscales.

 

          Without social support, child care, education on healthy behaviors, safe environments or transportation, women in a variety of settings undergo lifestyle and psychosocial changes that lead to postpartum weight gain, inactivity, isolation and depression.  When combined with the positive effects of group support and the health effects of regular physical activity, one can see why postpartum group exercise produces positive psychological outcomes [19].

 

 

References

1. ACOG. Exercise during pregnancy and the postpartum period. ACOG Committee Opinion No. 267. Obstet Gynecol 99:171-173. 2002.

2. American College of Sports Medicine. Impact of physical activity during pregnancy and postpartum on chronic disease risk. Med Sci Sprts Exerc 38(5):989-1006. 2006.

3. Joint SOGC/CSEP Clinical Practice Guideline. No. 129, June 2003. Exercise in Pregnancy and the Postpartum Period.  Society of Obstetricians and Gynaecologists of Canada and the Canadian Society for Exercise Physiology.

4. Kramer M, McDonald S. Regular aerobic exercise during pregnancy. Cochrane Database Syst Rev. Art. No.: CD000180. 2006. doi: 10.1002/14651858.CD000180,pub2.

5. Bordulin KM, Evenson KR, Wen F, Herring AH, Benson AM. Physical Activity Patterns During Pregnancy, Med Sci Sports Exerc 40(11):1901-1908. 2008.

6. Clapp JF III. 2003. The effects of maternal exercise on fetal oxygenation and feto-placental growth. Eur J Ob Gyn Reprod Biol. 110 Suppl 1:S80-5.

7. Rudra C.B., Williams M.A., Lee I.M., Miller R.S., Sorensen T.K. 2005. Perceived exertion during prepregnancy physical activity and preeclampsia risk. Medicine & Science in Sports & Exercise, 37(11), 1836-41.

8. Clapp, JF III, et al. 1999.  Neonatal behavioral profile of the offspring of women who continued exercise regularly throughout pregnancy.  Am J Ob Gyn 180(1): 91-94.                    

9. Clapp, JF III, et al. 1998.  The one-year morphometric and neurodevelopmental outcome for the offspring of women who continued to exercise regularly throughout pregnancy, Am J Ob Gyn 178(3): 594-9.

10. May LE et al. 2008. Exercise During Pregnancy Benefits Baby. Experimental Biology 2008 scientific conference; 121st annual meeting of the American Physiological Society.

11. Ohtake, PJ and Wolfe, LA. 1998. Physical conditioning attenuates respiratory responses to steady state in gestation, J Appl Physiol 83(2):644-51.

12. Clapp JF III. Exercise during pregnancy may improve perimenopausal fitness, Am J Obstet Gynecol. 2008;199:489.e1-489.e6.

13. VD Garovic, MD; SR Hayman. 2007. Hypertension in Pregnancy:  An emerging risk factor for cardiovascular disease. Nat Clin Pract Nephrol.  3(11):613-622.

14. McDonald SD, Malinowski A, Zhou Q, Yusuf S, Devereaux PJ. 2008. Cardiovascular Sequelae of Preeclampsia/Eclampsia: A Systematic Review and Meta-Analyses. Am Heart J.;156(5):918-930.

15. Brankston GN, Mitchell BF, Ryan EA, Okun NB. 2004. Resistance exercise decreases the need for insulin in overweight women with gestational diabetes mellitus. AJOG. 190(1): 188-193.

16. Benson, H. 1975. The Relaxation Response. New York: Morrow.

17. Shamanthakamiani, N et al. 2005. Efficacy of yoga on pregnancy outcome, J Altern Compl Med 11(2):237-244.

18.  Sampselle, CM et al. 1999. Physical activity and postpartum well-being. JOGNN 28(1):41-49.
19.  Blum, JW, Beaudoin, CM and Caton-Lemos, L. 2004. Physical activity patterns and maternal well-being in postpartum women. Maternal and Child Health Journal 8(3)163-169.

 

 

Ann F. Cowlin MA, CSM, CCE
Email: anncowlin@sbcglobal.net                   
Blog: http://dancingthrupregnancy.wordpress.com/
Website: www.dancingthrupregnancy.com
Founder, Dancing Thru Pregnancy®, Inc.               
Movement Specialist, Yale University Athletic Department
Executive Director, Women’s Health Fitness Institute
Author, Women’s Fitness Program Development (Human Kinetics, 2002)
Author, “Women and Exercise” in Varney’s Midwifery (Jones & Blackwell, 1996,
2003 and upcoming edition)
Expert consultant, Pregnancy and Postpartum Physical Training, U.S. Army