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Physiology and practical implications of dynamic exercise in pregnancy

Published online by Cambridge University Press:  10 October 2008

Marieke B van Doorn
Affiliation:
Department of Obstetrics and Gynecology, Erasmus University Medical School, Rotterdam, The Netherlands
Frederik K Lotgering*
Affiliation:
Department of Obstetrics and Gynecology, Erasmus University Medical School, Rotterdam, The Netherlands
Henk CS Wallenburg
Affiliation:
Department of Obstetrics and Gynecology, Erasmus University Medical School, Rotterdam, The Netherlands
*
Frederik K Lotgering, Department of Obstetrics and Gynecology, EE 2283, PO Box 1738, 3000 DR Rotterdam, The Netherlands

Extract

In pregnancy the uterus and its contents constitute a growing mass of tissue with an increasing need for oxygen and substrates. Muscle activity is associated with an even more dramatic increase in metabolic demands. One might question if the physiological adaptations are adequate to provide for the combined demands of exercise and pregnancy.

Type
Articles
Copyright
Copyright © Cambridge University Press 1991

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References

1 Lotgering, FK, Gilbert, RD, Longo, LD. Maternal and fetal responses to exercise during pregnancy. Physiol Rev 1985; 65: 136.CrossRefGoogle ScholarPubMed
2 Clapp, JF. The effects of maternal exercise on early pregnancy outcome. Am J Obstet Gynecol 1989; 161: 1453–57.CrossRefGoogle ScholarPubMed
3 Åstrand, P-O, Rodahl, K. Textbook of work physiology. Physiological basis of exercise. 3rd edition. New York: McGraw-Hill, 1986.Google Scholar
4 Brück, K. Heat production and temperature regulation. In: Stave, U ed, Perinatal physiology. New York: Plenum, 1978: 455–98.Google Scholar
5 Carpenter, MW, Sady, SP, Sady, MA, Haydon, B, Coustan, DR, Thompson, PD. Effect of maternal weight gain during pregnancy on exercise performance. J Appl Physiol 1990; 68: 1173–76.CrossRefGoogle ScholarPubMed
6 Pernoll, ML, Metcalfe, J, Schlenker, TL, Welch, JE, Matsumoto, JA. Oxygen consumption at rest and during exercise in pregnancy. Respir Physiol 1975; 25: 285–93.CrossRefGoogle ScholarPubMed
7 Clapp, JF. Cardiac output and uterine blood flow in the pregnant ewe. Am J Obstet Gynecol 1978; 130: 419–23.CrossRefGoogle ScholarPubMed
8 Ueland, K, Novy, MJ, Petersen, EN, Metcalfe, J. Maternal cardiovascular dynamics. IV: The influence of gestational age on the maternal cardiovascular response to posture and exercise. Am J Obstet Gynecol 1969; 104: 856–64.CrossRefGoogle ScholarPubMed
9 Morton, MJ, Paul, MS, Metcalfe, J. Exercise during pregnancy. Med Clin North Am 1985; 69: 97108.Google Scholar
10 Kusche, M, Bolte, A, Hollmann, W, Roemer, D. Körperliche Leistungsfähigkeit im Verlauf der Schwangerschaft. Geburtsh u Frauenheilk 1986; 46: 151–56.Google Scholar
11 Artal, R, Wiswell, R, Romem, Y, Dorey, F. Pulmonary responses to exercise in pregnancy. Am J Obstet Gynecol 1986; 154: 378–83.Google Scholar
12 Sady, SP, Carpenter, MW, Sady, MA et al. Prediction of VO2 max during cycle exercise in pregnant women. J Appl Physiol 1988; 65: 657–61.Google Scholar
13 Sady, SP, Carpenter, MW, Thompson, PD, Sady, MA, Haydon, B, Coustan, DR. Cardiovascular response to cycle exercise during and after pregnancy. J Appl Physiol 1989; 66: 336–41.CrossRefGoogle Scholar
14 Sady, MA, Haydon, BB, Sady, SP, Carpenter, MW, Thompson, PD, Coustan, DR. Cardiovascular response to maximal cycle exercise during pregnancy and at two and seven months postpartum. Am J Obstet Gynecol 1990; 162: 1181–85.Google Scholar
15 Lotgering, FK, van Doorn, MB, Struijk, PC, Pool, J, Wallenburg, HCS. Maximal aerobic exercise in pregnant women: heart rate, oxygen consumption, carbon dioxide production and ventilation. J App Physiol 1991; 70: 1016–23.Google Scholar
16 Lotgering, FK, Struijk, PC, van Doorn, MB, Wallenburg, HCS. Errors in predicting maximal oxygen consumption in pregnant and postpartum women (unpublished observations).Google Scholar
17 Wallenburg, HCS. Maternal haemodynamics in pregnancy. Fetal Medicine Review 1990; 2: 4566.Google Scholar
18 Ueland, K, Hansen, JM. Maternal cardiovascular dynamics. II. Posture and uterine contractions. Am J Obstet Gynecol 1969; 103: 17.Google Scholar
19 Knuttgen, HG, Emerson, K Jr. Physiological response to pregnancy at rest and during exercise. J Appl Physiol 1974; 36: 549–53.Google Scholar
20 Morton, MJ, Paul, MS, Campos, GR, Hart, MV, Metcalfe, J. Exercise dynamics in late gestation: effects of physical training. Am J Obstet Gynecol 1985; 152: 9197.CrossRefGoogle ScholarPubMed
21 Guzman, CA, Caplan, R. Cardiorespiratory response to exercise during pregnancy. Am J Obstet Gynecol 1970; 108: 600605.Google Scholar
22 von, Schweingel S, Lauckner, W. Untersuchungen zurkörperlichen Leistungfähigkeit im Verlauf der Schwangerschaft. Zbl Gynäkol 1984; 106: 535–44.Google Scholar
23 Berg, A, Mross, F, Hillemans, HG, Keul, J. Die Belastbarkeit der Frau in der Schwangerschaft. Med Welt 1977; 28: 1267–69.Google Scholar
24 Cooper, KA, Hunyor, SN, Boyce, ES, O’Neill, ME, Frewin, DB. Fetal heart rate and maternal cardiovascular and catecholamine responses to dynamic exercise. Aust NZ J Obstet Gynaecol 1987; 27: 220–23.Google Scholar
25 Dibblee, L, Graham, TE. A longitudinal study of changes in aerobic fitness, body composition, and energy intake in primigravid patients. Am J Obstet Gynecol 1983; 147: 908–14.Google Scholar
26 Lehmann, V, Regnat, K. Untersuchung zurkörperlichen Belastungfähigkeit schwangerer Frauen. Der Einfluss standardisierter Arbeit auf Herzkreislaufsystem, Ventilation, Gasaustausch, Kohlenhydratstoffwechsel und Säure-Basen-Haushalt. Z Geburtsh Perinatol 1976; 180: 279–89.Google Scholar
27 McMurray, RG, Katz, VL, Berry, MJ, Cefalo, RC. Cardiovascular responses of pregnant women during aerobic exercise in water: a longitudinal study. Int J Sports Med 1988; 9: 443–47.CrossRefGoogle ScholarPubMed
28 Greenleaf, JE, van Beaumont, W, Brock, PJ, Morse, JT, Mangseth, GR. Plasma volume and electrolyte shifts with heavy exercise in sitting and supine positions. Am J Physiol 1979; 236: 206–14.Google Scholar
29 Lotgering, FK, Gilbert, RD, Longo, LD. Exercise responses in pregnant sheep: oxygen consumption, uterine blood flow, and blood volume. J App Physiol 1983; 55: 834–41.Google Scholar
30 van Doorn, MB, Lotgering, FK, Struijk, PC, Pool, J, Wallenburg, HCS. Maternal and fetal cardiovascular responses to strenuous bicycle exercise (unpublished observations).Google Scholar
31 Eneroth-Grimfors, E, BevegÅrd, S, Nillson, BA, Sätterström, G. Effect of exercise on catecholamines and plasma renin activity in pregnant women. Acta Obstet Gynecol Scand 1988; 67: 519–23.CrossRefGoogle ScholarPubMed
32 Morris, N, Osborne, SB, Wright, HP, Hart, A. Effective uterine blood-flow during exercise in normal and pre-eclamptic pregnancies. Lancet 1956; ii: 481–84.CrossRefGoogle Scholar
33 Hohimer, AR, Bissonnette, JM, Metcalfe, J, McKean, TA. Effect of exercise on uterine blood flow in the pregnant pygmy goat. Am J Physiol 1984; 246: H20712.Google ScholarPubMed
34 Rauramo, I, Forss, M. Effect of exercise on maternal hemodynamics and placental blood flow in healthy women. Acta Obstet Gynecol Scand 1988; 67: 2126.CrossRefGoogle ScholarPubMed
35 Baumann, H, Huch, A, Huch, R. Doppler sonographic evaluation of exercise-induced blood flow velocity and waveform changes in fetal, uteroplacental and large maternal vessels in pregnant women. J Perinat Med 1989; 17: 279–87.CrossRefGoogle ScholarPubMed
36 Drack, G, Kirkinen, P, Baumann, H, Müller, R, Huch, R. Doppler-sonographische Untersuchungen vor und nach mütterlicher Kurzzeitbelastung in der Spätschwangerschaft. Z Geburtsh Perinat 1988; 192: 173–77.Google Scholar
37 Moore, DH, Jarrett, JC, Bendick, PJ. Exercise-induced changes in uterine artery blood flow, as measured by Doppler ultrasound, in pregnant subjects. Am J Perinatol 1988; 5: 9497.Google Scholar
38 Steegers, EAP, Buunk, G, Binkhorst, RA, Jongsma, JW, Wijn, PFF, Hein, PR. The influence of maternal exercise on the utero-placental vascular bed resistance and the fetal heart rate during normal pregnancy. Eur J Obstet Gynecol Reprod Biol 1988; 28: 2126.CrossRefGoogle Scholar
39 Chandler, KD, Leury, BJ, Bird, AR, Bell, AW. Effects of under-nutrition and exercise during late pregnancy on uterine, fetal and uteroplacental metabolism in the ewe. Br J Nutr 1985; 53: 625–35.Google Scholar
40 Clapp, JF. Acute exercise stress in the pregnant ewe. Am J Obstet Gynecol 1980; 136: 489–94.Google Scholar
41 Lotgering, FK, Gilbert, RD, Longo, LD. Exercise responses in pregnant sheep: blood gases, temperatures and fetal cardiovascular system. J Appl Physiol 1983; 55: 842–50.CrossRefGoogle ScholarPubMed
42 Dominguez de, Costa C, Lerdo de, Tejada A, Eisenberg de, Smoler P et al. Descenso en la excrecion de Ac. 5-HIAA production por el ejercicio en la embarazada. Ginec Obstet Méx 1978; 44: 347–53.Google Scholar
43 Werkö, L. Pregnancy and heart disease. Acta Obstet Gynecol Scand 1954; 33: 162–83.CrossRefGoogle ScholarPubMed
44 Bell, AW, Hales, JRS, Fawcett, AA, King, RB. Effects of exercise and heat stress on regional blood flow in pregnant sheep. J Appl Physiol 1986; 60: 1759–64.Google Scholar
45 Bonica, JJ. Maternal respiratory changes during pregnancy and parturition. In: Marx, GF ed, Clinical anesthesia, Vol 10/2, Parturition and perinatology. Philadelphia: FA Davis, 1973: 119.Google Scholar
46 Weinberger, SE, Weiss, ST, Cohen, WR, Weiss, JW, Johnson, TS. Pregnancy and the lung. Am Rev Respir Dis 1980; 121: 559–81.Google Scholar
47 Metcalfe, J, McAnulty, JL, Ueland, K. Cardiovascular physiology. Clin Obstet Gynecol 1981; 24: 693710.Google Scholar
48 Novy, MJ, Edwards, MJ. Respiratory problems in pregnancy. Am J Obstet Gynecol 1967; 99: 1042–45.Google Scholar
49 Edwards, MJ, Metcalfe, J, Dunham, J, Paul, MS. Accelerated respiratory response to moderate exercise in late pregnancy. Respir Physiol 1981; 45: 229–41.CrossRefGoogle ScholarPubMed
50 Effkemann, G, Borgard, W. Die Leistungsfähigkeit des Kreislaufes der Schwangeren und Wöchnerinnen. Eine Studie des 02-Haushaltes in der Ruhe und unter Belastung. Arch Gynäk 1938; 167: 539–63.CrossRefGoogle Scholar
51 Eismeyer, G, Pohl, A. Untersuchungen über den Kreislauf und den Gasstoffwechsel in der Schwangerschaft bei Arbeitsversuchen. Arch Gynäk 1934; 156: 428–53.CrossRefGoogle Scholar
52 Widlund, G. The cardio-pulmonal function during pregnancy. A clinical-experimental study with particular respect to ventilation and oxygen consumption among normal cases in rest and after work tests. Acta Obstet Gynecol Scand 1945; 25(suppl 1): 1125.Google Scholar
53 Williams, A, Reilly, T. Investigation of changes in responses to exercise and in mood during pregnancy. Ergonomics 1988; 31: 1539–49.CrossRefGoogle ScholarPubMed
54 Pernoll, ML, Metcalfe, J, Kovach, PA, Wachtel, R, Dunham, MJ. Ventilation during rest and exercise in pregnancy and postpartum. Respir Physiol 1975; 25: 295310.CrossRefGoogle ScholarPubMed
55 Berry, MJ, McMurray, RG, Katz, VL. Pulmonary and ventilatory responses to pregnancy, immersion, and exercise. J Appl Physiol 1989; 66: 857–62.Google Scholar
56 Wasserman, K, Whipp, BJ, Casaburi, R. Respiratory control during exercise. In: Chevniack, NS, Widdicombe, JG eds. Handbook of physiology. American Physiological Society, 1986: 595619.Google Scholar
57 Bedell, GN, Adams, RW. Pulmonary diffusing capacity during rest and exercise. A study of normal persons and persons with atrial septal defect, pregnancy, and pulmonary disease. J Clin Invest 1962; 41: 1908–23.Google Scholar
58 Asmussen, E. Muscular exercise. In: Fenn, WO, Rahn, H eds, Handbook of physiology, Section 3: Respiration. Washington DC: American Physiological Society, 1965: II; 939–78.Google Scholar
59 Dempsey, JA, Vidruk, H, Mastenbrook, SM. Pulmonary control systems in exercise. Fed Proc 1980; 39: 14981505.Google Scholar
60 Maršál, K, Gennser, G, Löfgren, O. Effects on fetal breathing movements of maternal challenges. Crossover study on dynamic work, static work, passive movements, hyperventilation and hyperoxygenation. Acta Obstet Gynecol Scand 1979; 58: 335–42.Google Scholar
61 Christensen, EH, Hansen, O. Arbeitsfähigkeit und Ernährung III. Scand Arch Physiol 1939; 81: 160–71.Google Scholar
62 Kalhan, SC, D' Angelo, LJ, Savin, SM, Adam, PAJ. Glucose production in pregnant women at term gestation. Sources of glucose for human fetus. J Clin Invest 1979; 63: 388–94.Google Scholar
63 McMurray, RG, Katz, VL, Berry, MJ, Cefalo, RC. The effect of pregnancy on metabolic responses during rest, immersion, and cardiac exercise in water. Am J Obstet Gynecol 1988; 158: 481–86.Google Scholar
64 Artal, R, Platt, LD, Sperling, M, Kammula, RK, Jilek, J, Nakamura, R. Exercise in pregnancy. I: Maternal cardiovascular and metabolic responses in normal pregnancy. Am J Obstet Gynecol 1981; 140: 123–27.Google Scholar
65 Artal, R, Rutherford, S, Romem, Y, Kammula, RK, Dorey, FJ, Wiswell, RA. Fetal heart rate responses to maternal exercise. Am J Obstet Gynecol 1986; 155: 729–33.Google Scholar
66 Rauramo, I, Salminen, K, Laatikainen, T. Release of β-endorphins in response to physical exercise in nonpregnant and pregnant women. Acta Obstet Gynecol Scand 1986; 65: 609–12.Google Scholar
67 Clapp, JF, Wesley, M, Slaemaker, RH. Thermoregulatory and metabolic responses to jogging prior to and during pregnancy. Med Sci Sports Exerc 1987; 19: 124–30.Google Scholar
68 Felig, P, Wahren, J, Hendler, R, Ahlborg, G. Plasma glucose levels in exercising man. N Engl J Med 1972; 287: 184–85.CrossRefGoogle Scholar
69 Battaglia, FC, Meschia, G. Foetal and placental metabolisms: their interrelationship and impact upon maternal metabolism. Proc Nutr Soc 1981; 40: 99113.Google Scholar
70 Yen, SC. Metabolic homeostasis during pregnancy. In: Yen, SC, Jaffe, RB eds, Reproductive endocrinology, physiology, pathophysiology and clinical management. Philadelphia: WB Saunders, 1978: 537–63.Google Scholar
71 Bottger, I, Sehlein, EM, Faloona, GR, Knochel, JP, Unger, RH. The effect of exercise on glucagon secretion. J Clin Endocrinol Metabol 1972; 35: 117–25.CrossRefGoogle ScholarPubMed
72 Terjung, RL. Endocrine systems. In: Strauss, RH ed, Sport medicine and physiology. Philadelphia: WB Saunders, 1979: 147–65.Google Scholar
73 Artal, R, Wiswell, R, Romem, Y. Hormonal responses to exercise in diabetic and nondiabetic pregnant patients. Diabetes 1985; 34: 7880.CrossRefGoogle ScholarPubMed
74 Jovanovic, L, Kessler, A, Peterson, CM. Human maternal and fetal response to graded exercise. J Appl Physiol 1985; 58: 1719–22.Google Scholar
75 Few, JD. Effect of exercise on the secretion and metabolism of cortisol in man. J Endocrinol 1974; 62: 341–53.Google Scholar
76 Rauramo, I, Andersson, B, Laatikainen, T, Pettersson, J. Stress hormones and placental steroids in physical exercise during pregnancy. Br J Obstet Gynaecol 1982; 89: 921–25.Google Scholar
77 Platt, LD, Artal, R, Semel, J, Sipos, L, Kammula, RK. Exercise in pregnancy. II: Fetal responses. Obstet Gynecol 1983; 147: 487–91.Google ScholarPubMed
78 Broughton Pipkin, F. The renin-angiotensin system in normal and hypertensive pregnancies. In: Rubin, PC ed, Hypertension in pregnancy. Amsterdam: Elsevier, 1988: 118–51.Google Scholar
79 Morley, JE. The endocrinology of the opiates and opioid peptides. Metabolism 1981; 30: 195209.CrossRefGoogle ScholarPubMed
80 Rahkila, P, Hakala, E, Salminen, K, Laatikainen, T. Response of plasma endorphins to running exercises in male and female endurance athletes. Med Sci Sports Exerc 1987; 19: 451–55.CrossRefGoogle ScholarPubMed
81 Lovelady, CA, Lonnerdal, B, Dewey, KG. Lactation performance of exercising women. Am J Clin Nutr 1990; 52: 103109.CrossRefGoogle ScholarPubMed
82 Verhoeff, A, Garfield, RE, Ramondt, J, Wallenburg, HCS. Electrical and mechanical uterine activity and gap junctions in peripartal sheep. Am J Obstet Gynecol 1985; 153: 447–54.CrossRefGoogle ScholarPubMed
83 Hytten, FE, Leitch, I. The physiology of human pregnancy. Oxford: Blackwell, 1964.Google Scholar
84 Jones, RL, Botti, JJ, Anderson, WM, Bennett, NL. Thermoregulation during aerobic exercise in pregnancy. Obstet Gynecol 1985; 65: 340–45.Google Scholar
85 Erkkola, R. The influence of physical training during pregnancy on physical work capacity and circulatory parameters. Scand J Clin Lab Invest 1976; 36: 747–54.Google Scholar
86 South-Paul, JE, Rajagopal, KR, Tenholder, MF. The effect of participation in a regular exercise program upon cardiac capacity during pregnancy. Obstet Gynecol 1988; 71: 175–79.Google Scholar
87 Dressendorfer, RH. Physical training during pregnancy and lactation. Phys Sportsmed. 1978; 6: 7480.CrossRefGoogle ScholarPubMed
88 Clapp, JF. Oxygen consumption during treadmill exercise before, during and after pregnancy. Am J Obstet Gynecol 1989; 161: 1458–64.CrossRefGoogle Scholar
89 Collings, CA, Curet, LB, Mullin, JP. Maternal and fetal responses to a maternal aerobic exercise program. Am J Obstet Gynecol 1983; 145: 702707.Google Scholar
90 Jarrahi-Zadeh, A, Kane, FJ, van de Kastif, RL, Lachenbruch, PA, Ewing, JA. Emotional and cognitive changes in pregnancy and early puerperium. Br J Psychiat 1969; 115: 797805.Google Scholar
91 Wallace, AM, Boyer, DB, Dan, A, Holm, K. Aerobic exercise, maternal self-esteem, and physical discomforts during pregnancy. J Nurse Midwif 1986; 31: 255–62.Google Scholar
92 Hall, DC, Kaufmann, DA. Effects of aerobic and strength conditioning on pregnancy outcomes. Am J Obstet Gynecol 1987; 157: 1199–203.CrossRefGoogle ScholarPubMed
93 Zaharieva, E. Olympic participation by women. Effects on pregnancy and childbirth. JAMA 1972; 221: 992–95.CrossRefGoogle ScholarPubMed
94 Hale, RW. Exercise and pregnancy, how each affects the other. Postgrad Med 1987; 82: 6163.CrossRefGoogle ScholarPubMed
95 MacLennan, AH, Green, RC, Nicolson, R, Bath, M. Serum relaxin and pelvic pain of pregnancy. Lancet ii: 1986; 243–45.Google Scholar
96 Hummel, P. Changes in posture during pregnancy. Amsterdam: Free University, 1987 [Doctoral Thesis].Google Scholar
97 Abramson, D, Roberts, SM, Wilson, PD. Relaxation of the pelvic joints in pregnancy. Surg Gynecol Obstet 1934; 58: 595613.Google Scholar
98 Calguneri, M, Bird, HA, Wright, V. Changes in joint laxity occurring during pregnancy. Ann Rheum Dis 1982; 41: 126–28.Google Scholar
99 Arfi, JS, Peres, G. Fréquences cardiaques maternelles et foetales lors d’exercises sur ergocycle. J Gynecol Obstet Biol Reprod 1986; 15: 281–86.Google Scholar
100 von Zahn, V, Raabe, V. Uber die Einwirkung der Schwangerengymnastik auf die Schwangerschaftskontraktionen. Zbl Gynäkol 1984; 106: 3339.Google Scholar
101 Durak, EP, Jovanovic-Peterson, L, Peterson, CM. Comparative evaluation of uterine response to exercise on five aerobic machines. Am J Obstet Gynecol 1990; 162: 754–56.Google Scholar
102 Rauramo, I. Effect of short-term physical exercise on foetal heart rate and uterine activity in normal and abnormal pregnancies. Ann Chir Gynaecol 1987; 76: 16.Google Scholar
103 Hauth, JC, Gilstrap, LC, Widmer, K. Fetal heart rate reactivity before and after maternal jogging during the third trimester. Am J Obstet Gynecol 1982; 142: 545–47.Google Scholar
104 Baumann, H, Bung, P, Fallenstein, F, Huch, A, Huch, R. Reaktion von Mutter und Fetus auf die köreperliche Belastung in der Höhe. Gebursth u Frauenheilk 1985; 45: 869–76.CrossRefGoogle Scholar
105 Veille, JC, Hohimer, AR, Burry, K, Speroff, L. The effect of exercise on uterine activity in the last eight weeks of pregnancy. Am J Obstet Gynecol 1985; 151: 727–30.Google Scholar
106 Clapp, JF, Dickstein, S. Endurance exercise and pregnancy outcome. Med Sci Sports Exerc 1984; 16: 556–62.Google Scholar
107 Pomerance, JJ, Gluck, L, Lynch, VA. Physical fitness in pregnancy: its effect on pregnancy outcome. Am J Obstet Gynecol 1974; 119: 867–76.Google Scholar
108 Dale, E, Mullinax, KM, Bryan, DH. Exercise during pregnancy: effects on the fetus. Can J Appl Spt Sci 1982; 7: 98103.Google Scholar
109 Erkkola, R. The physical work capacity of the expectant mother and its effect on pregnancy, labor and the newborn. Int J Gynaecol Obstet 1976; 14: 153–59.CrossRefGoogle ScholarPubMed
110 Kulpa, PJ, White, BM, Visscher, R. Aerobic exercise in pregnancy. Am J Obstet Gynecol 1987; 156: 1395–403.Google Scholar
111 Wong, SC, McKenzie, DC. Cardiorespiratory fitness during pregnancy and its effects on outcome. Int J Sports Med 1987; 8: 7983.CrossRefGoogle ScholarPubMed
112 Jarrett, JC, Spellacy, WN. Jogging during pregnancy: an improved outcome?. Obstet Gynecol 1983; 61: 705709.Google Scholar
113 Jarski, RW, Trippett, DL. The risks and benefits of exercise during pregnancy. J Fam Pract 1990; 30: 185–89.Google Scholar
114 Paisley, JE, Mellion, MB. Exercise during pregnancy. Am Fam Physician 1988; 38: 143–50.Google ScholarPubMed
115 Lotgering, FK, van den Berg, A, Struijk, PC, Wallenberg, HCS. Arterial pressure response to maximal isometric exercise in pregnant women (unpublished observations).Google Scholar
116 Kuntz, WD. Water ski spill and partial avulsion of the uterine cervix. N Engl J Med 1983; 309: 990.Google Scholar
117 Clapp, JF. Körperliche Arbeit und Sport während der Schwangerschaft. Gynäkologe 1987; 20: 144–50.Google Scholar
118 Clapp, JF. Exercise in pregnancy: a brief clinical review. Fetal Medicine Review 1990; 2: 89101.Google Scholar
119 Mullinax, KM, Dale, E. Some considerations of exercise during pregnancy. Clin Sports Med 1986; 5: 559–70.CrossRefGoogle ScholarPubMed
120 Smith, DW, Clarren, SK, Sedgwick-Harvey, MA. Hyperthermia as a possible teratogenic agent. J Pediatr 1978; 92: 878–83.Google Scholar
121 Bolton, ME. Scuba diving and fetal well-being: a survey of 208 women. Undersea Biomed Res 1980; 7: 183–89.Google ScholarPubMed
122 American College of Obstetricians and Gynecologists. Home exercise programs. Exercise during pregnancy and the postnatal period. Washington DC: American College of Obstetricians and Gynecologists, 1985: 4.Google Scholar