Effect of exercise on cardiac output and distribution of uterine blood flow in pregnant ewes

Abstract

This study was designed to determine what effect physical training has on heart rate and stroke volume responses to exercise stress and to determine if exercise altered the distribution of uterine blood flow. Measurements were made in ten pregnant ewes at rest and immediately following exercise on a treadmill. Five ewes underwent physical training for 3 wk prior to measurement. An increase in heart rate with no change in stroke volume was observed following exercise in both trained and untrained ewes. Total uterine blood flow was not changed following exercise, but distribution was altered in favor of the placenta. Blood flow was evenly distributed within the placenta before and after exercise. The redistribution of flow to the placenta that occurs after exercise. tphe redistribution of flow to the placenta that occurs after exercise might represent a compensatory mechanism for the fetus.

Effects of Exercise on Fetal-Placental Growth and Uteroplacental Blood Flow in the Rat

“…The dramatic effects of exercise on preg nancy in the rat, guinea pig [18] and mouse [12] contrast with the negligible effects that exercise induced on UBF or pregnancy in ewes [19,20]. These species differences may be attributed to differences in both placental structure and vascular supply patterns, exer cise regimes, or other factors unique to either model or testing system.…”

Physiology of Prenatal Exercise and Fetal Development

“…Some studies have found no relationship between mode of delivery and maternal activity during gestation (Sternfeld et al 1995;Horns et al 1996;Kennelly et al 2002b;Magann et al 2002;Barakat et al 2009b). Other research, however, has found participation in exercise while pregnant is associated with lower rates of cesarean section and less complications (Curet et al 1976;Dale et al 1982;Hall and Kaufmann 1987;Clapp 1990;Clapp and Capeless 1990;Hatch et al 1993). Women who exercise during pregnancy also report lower perceived exertion during labor, than women who did not exercise (Rice and Fort 1991).…”

“…Yes, exercise by the mother has been implied to decrease the risk of a large for gestational age infant. Conversely, some neonates exposed to maternal exercise were normal weight, but lighter than neonates not exposed (Curet et al 1976;Collings et al 1983;Clapp and Dickstein 1984;Clapp and Capeless 1990;Bell and Sejnowski 1995;Kardel and Kase 1998;Clapp 2000;Kramer 2000;Marquez-Sterling et al 2000). These latter studies are associated with a moderate to high volume of exercise (5 days per week or more) in the last half of pregnancy.…”

“…Preterm labor is defined as delivering beforeMany studies have found maternal physical activity during pregnancy is not associated with the occurrence or increased occurrence of preterm labor (Curet et al 1976;Collings et al 1983;Jarrett and Spellacy 1983;Botkin and Driscoll 1991;Hatch et al 1993;Clapp 1994;Florack et al 1995;Sternfeld et al 1995;Horns et al 1996;Rao et al 1998;Clapp 2000;Magann et al 2002;Leiferman and Evenson 2003;Misra et al 2003;Gavard and Artal 2008). Likewise, research reporting gestational age at delivery finds no difference between neonates of exercising or non-exercising women (Koemeester et al 1995;Sternfeld et al 1995;Horns et al 1996).…”

“…Many studies show that maternal exercise has no effect on neonatal apgar scores (Curet et al 1976;Collings et al 1983;Clapp and Dickstein 1984;Botkin and Driscoll 1991;Kardel and Kase 1998;Kramer 2000;Marquez-Sterling et al 2000;Magann et al 2002). Even obese women who exercised while pregnant delivered babies who had normal apgar scores (Lindholm et al 2010).…”