LAUSR

RESEARCH QUESTION How does use of a levonorgestrel-releasing intrauterine system (LNG-IUS) in infertile women with endometrial hyperplasia without atypia affect endometrial hyperplasia regression and pregnancy rates compared with oral medroxyprogesterone acetate (MPA)? DESIGN This prospective cohort study included 215 infertile women with an indication for assisted reproductive technology (ART) and a diagnosis of endometrial hyperplasia without atypia. Endometrial hyperplasia was diagnosed by hysteroscopic endometrial biopsy. At the time of first- and second-line treatment, patients were offered therapy with either oral MPA 10 mg daily or LNG-IUS. Follow-up biopsies were scheduled after 90 days' treatment. After endometrial hyperplasia regression, patients were admitted to IVF/intracytoplasmic sperm injection (ICSI) cycles. RESULTS Baseline characteristics and confounders including age at diagnosis, body mass index and duration of infertility did not differ between LNG-IUS users and control participants and were accounted for using propensity score weighting. Endometrial hyperplasia regression rate at first follow-up was higher in the LNG-IUS group than the oral progestins group (28/28, 100% and 110/187, 58.8%; P < 0.001), while that after second-line treatment was comparable between the two groups (89/91, 97.8% and 122/124, 98.4%; P = 0.22). Clinical pregnancy rate, miscarriage rate and cumulative live birth rate following ART in patients ever receiving LNG-IUS were similar to those of patients receiving only MPA (34% versus 39.5%, 22.6% versus 34.7% and 26.4% versus 25.8%). CONCLUSION Endometrial hyperplasia regression is greater in women receiving LNG-IUS compared with oral MPA, while live birth rates following ART are comparable between the two groups. The use of LNG-IUS does not jeopardize the chances of pregnancy in women seeking fertility treatment.