Uterine Blood Flow Indices in Sheep during Pregnancy

To understand the different changes and events that occur in humans from conception until labour our experimental animal model is the ewe. Some studies use laboratory rodents, non-human primates and domestic ruminants as a model for research relevant to human pregnancies.1 Sheep, humans and other higher primates have villous interdigitation, wherein the chorion has a tree-like branching pattern, and villi either fit into endometrial crypts or are they are directly bathed in maternal blood.2 Furthermore, Pelage et al. demonstrated that the uterine vascularization of non-pregnant sheep is similar to that of women; so the sheep represents an appropriate animal model for experimental uterine artery embolization.3 The previous authors analysed the anatomy of the uterine vascularature in nonpregnant ewes by following the tributaries and anastomoses of the middle uterine artery which is considered to be the main arterial supply for the uterine vasculature. As described in Figure 1, the origin of the uterine artery from the internal iliac artery was similar to that in women.3,4