The uterine hemodynamic response to repetitive unilateral vascular embolization in the pregnant ewe

The longitudinal hemodynamic response of the uterine circulation to pregnancy and to repetitive embolic insult was assessed in 23 singleton ewe pregnancies by means of electromagnetic flow transducers and radionuclide-labeled microspheres. The data indicate that the longitudinal hemodynamic changes observed in the uterine circulation were directly related to the growth rate of the tissue which it supplied. The hemodynamic impact of embolization appears to be secondary to its impact on tissue growth. Embolization simply blunts the normal incremental increases in uterine perfusion and the cross-sectional area of the uterine vascular bed. It alters actual tissue perfusion only within a portion of the cotyledonary circulation. Finally, the data support the presence of functional arterial anastomoses between the two sides of the uterine circulation in this species.