Levonorgestrel-impregnated Intrauterine device reduces occurrence of hyperplastic polyps: a population-based follow-up cohort study.

The main objective was to investigate if occurrence of hyperplastic polyps was reduced by use of the levonorgestrel-impregnated intrauterine system (LNG-IUS, Mirena®; Bayer) and if the LNG-IUS was more effective compared to oral medroxyprogesterone acetate (MPA) or observation-only. Patients (N=59) with hyperplastic polyps were given LNG-IUS, 10 mg oral MPA taken 10 days per cycle, or had observation-only for six months. Diagnosis of histological specimens was performed by light microscopy according to the WHO classification and D-score prior to and after six months therapy. No polyps were found in women treated with LNG-IUS (18/18). Five women treated with cyclic MPA (5/20, 25%) and two (2/21, 9%) with observation had normal endometrium without polyps after six months. No former study has shown that LNG-IUS is effective at reducing the occurrence of hyperplastic endometrial polyps. The effect is superior to that of oral progestin and observation-only.