Comparative analysis of endometrium after using levonorgestrel-releasing intrauterine system and copper intrauterine device

BACKGROUND: To date, the risks of pelvic inflammatory diseases, including chronic endometritis, associated with the use of various intrauterine contraceptives, have remained debatable. AIM: The aim of this study was to conduct a comparative analysis of the endometrial status in women of reproductive age after the use of copper- or levonorgestrel-releasing intrauterine device. MATERIALS AND METHODS: Morphological and immunohistochemical studies of endometrial biopsies obtained by aspiration Pipelle biopsy were performed after intrauterine device extraction in 18 patients who used a copper-containing intrauterine device and in 12 women who used the levonorgestrel-releasing intrauterine device Mirena. Monoclonal mouse antibodies to CD20, CD138, and α-smooth muscle actin (DAKO, Denmark) were used. Criteria for inclusion of patients in the study are reproductive age, use of an intrauterine device for five years, absence of complications associated with the intrauterine device during its use. Exclusion criteria are a history of pelvic inflammatory diseases, sexually transmitted infections, habitual miscarriage, two or more intrauterine interventions. RESULTS: After using a copper-containing intrauterine device, signs of chronic inflammation were found in the endometrium such as cytogenic stroma fibrosis with pronounced infiltration by inflammatory cells, positive expression of CD138 (33.3% of observations), CD20 (88.9% of observations with an average number of 27.4 ± 5.7), α-smooth muscle actin (up to 70% of the cytogenic stroma area), and the presence of lymphatic follicles consisting of B lymphocytes (33.3% of observations). During the use of the levonorgestrel-releasing intrauterine device, decidual transformation of cytogenic stroma cells, as well as secretion and atrophy of the glandular epithelium, were found in the endometrium. CD20-positive cells were detected in five out of 12 cases (41.6% of observations with an average number of 12.8 ± 4.6). Expression of CD138 and α-smooth muscle actin was not detected in any of the cases. CONCLUSIONS: The use of a copper-containing intrauterine device is associated with a high risk of developing chronic endometritis. The absence of signs of chronic inflammation in the endometrium after the use of a levonorgestrel-releasing intrauterine device is probably due to the protective effect of levonorgestrel on the uterine mucosa. Thus, levonorgestrel-releasing intrauterine devices, in comparison with copper-containing intrauterine devices, have a favorable safety profile relative to the endometrium and can be recommended for women of reproductive age, including those who have not given birth.