AJP - Regulatory, Integrative and Comparative Physiology, Vol 248, Issue 6 698-R701, Copyright © 1985 by American Physiological Society
A longitudinal study of cardiac output in unstressed pregnant guinea pigs
S. A. Myers and H. Y. Tseng
A previous study in pregnant guinea pigs failed to demonstrate any increase
in cardiac output when a group of pregnant animals was compared with four
nonpregnant animals. In the current study an increase in cardiac output of
35 +/- 14 (SE) ml/min, a 13% increase, was observed during an average 2-wk
interval between 44 and 58 days of pregnancy (P less than 0.05, term 68
days, n = 8). A significant increase in placental blood flow of 14.8 +/-
6.2 ml/min (42% increase, P less than 0.05) was also observed during this
interval without significant change in the percentage of cardiac output
going to the uterus. The data on cardiac output and its distribution to the
uteroplacental circulations are consistent with reports in other mammalian
species; to accommodate the increased demands of the uteroplacental
circulation, cardiac output increases as pregnancy advances. These data
demonstrate that multiple observations in the same animal describe cardiac
output and its distribution more accurately than a single observation.
