Effects of food restriction on cardiac ouput and blood flow to the uterus and placenta in the pregnant rat.

Cardiac output and blood flow to the uterus, ovary and placenta were determined at day 21 of gestation in rats fed ad libitum a standard diet or 50% of control intake from day 5 of gestation. Restricted rats had lower body weights, smaller fetuses and placentas and a marked reduction in blood flow to ovary and placenta but not to endometrium and myometrium. These animals also had a marked reduction in cardiac output. However, the percent distribution of cardiac output in the whole uterus, ovary and placenta was similar in control and restricted rats. Results suggest that food restriction decreases expansion in uterine and placental blood flow by interfering with the expansion in cardiac output which normally occurs in pregnancy.