CHANGES IN CARDIAC OUTPUT AND UTERINE BLOOD FLOW OF PREGNANT MACACA MULATTA

Progressive changes in the cardiovascular system were studied in a group of rhesus monkeys at various stages of gestation. On the basis of body weight, cardiac output increased 11 per cent and oxygen consumption 13 per cent during pregnancy. From 91 to 114 days' gestation, the uterine blood flow and oxygen consumption fell 6 per cent and 13 per cent, respectively, in relation to the weight of the pregnant uterus and its contents. Thereafter both blood flow and oxygen consumption were maintained at nearly steady levels until term. In midpregnancy the uterine-placental blood flow represented 2.6 per cent of left ventricular output while near term it was 8.6 per cent. No evidence of untoward effects of high oxygen tensions was observed in this study. © 1969.