Endometrial morphology during long-term use of levonorgestrel-releasing intrauterine devices.

Levonorgestrel-releasing intrauterine devices (IUD) were inserted in 92 women. Endometrial biopsies were taken between 3 months and 7 years after these insertions. Intrauterine release of levonorgestrel resulted in endometrial glandular atrophy and decidualized stroma. Inflammation and necrosis were also seen as local signs of IUD use. The biopsies were similar regardless of the duration of IUD use. Endometrial morphology returned to normal in biopsy specimens taken 1-3 months after IUD removal.