Effect of IUD on microcirculation in rabbit uterine endometrium

Insertion of an IUD into the uterine cavity could result in an obvious increase in endometrial microcirculation blood volume. The endometrial capillary configuration is a scattered, loose, and irregular capillary network. 8-10 months after IUD insertion in the uterine cavity, remarkable hyperplasia of the capillary and enlargement of the vessel diameter were observed in the IUD area. In the IUD depressed area, the capillaries had obviously increased and come together irregularly with various vessel diameters in the form of bead strings. The diameter of the vessels around most glandular opening enlarged and the capillaries clustered together to form a spherical capillary plexus. The end of the vessel dilated like a small sphere to form a microvascular bell. The more seriously depressed capillary became thinner, atrophied, and even cracked. Then, the newborn capillary trending along the IUD appeared. (author's modified)