RESUMO
OBJECTIVE: To study the effect of low-dose levonorgestrel contraceptive intrauterine systems (LNG-IUS-12) on endometrial morphology and ultrastructure. METHODS: Twenty seven women who desired contraception were inserted LNG-IUS-12. Endometrial biopsies were collected during the late proliferative phase of the cycle before (control) and after the use of the LNG-IUS for 36 months. The changes of morphology and ultrastructure of endometrium tissue were observed by light microscope and transmission electron microscope. RESULTS: After 36 months of use, the endometrial gland reduced in number and some were atrophic. A decidual change of stroma was present. Electronic microscopy demonstrated the presence of low columnar, karyopyknosis, and chromatin margination in the glandular epithelial cell. Some vacuolar degeneration in partial mitochondria and rough endoplasmic reticulum presented light extension. Changes could be concluded as cell inhibition of proliferation. CONCLUSIONS: The low-dose levonorgestrel-releasing intrauterine systems has a suppressive effect on endometrium that is similar to LNG-IUS.
