Ultrastructural comparative study on endometrium of Chinese women using intrauterine devices of stainless steel ring, copper T220, and releasing levonorgestrel: morphometry of microvessels.

An electron microscopic morphometric study was performed for three kinds of IUDs, the stainless steel ring (SS), the copper T220 (TCu) and the WHO levonorgestrel IUD (LNG), for comparison of their effects on microvessels of the endometrium of women wearing the devices. The morphometry of plasmolemmal vesicles (PV) of the endothelial cell as well as the contracted and degenerated endothelial cell were undertaken. The results showed that all three IUDs led to significant changes in blood vessels, i.e., a higher percentage of contracted and degenerated cells than in the control group (p less than 0.01), and an increase in PV after insertion of the devices (p less than 0.01). The TCu caused more contracted endothelial cells than the SS (p less than 0.01) and the LNG (p less than 0.05). The levonorgestrel-releasing IUD resulted in a higher increase of PV than the SS and the TCu. For the differences between bleeding and non-bleeding groups, only the TCu showed a higher percentage of contracted cells (p less than 0.05).