Use of progestin-containing intrauterine systems in hormone therapy regimens: what are the data?

The levonorgestrel intrauterine system (IUS) is frequently used in perimenopause for contraception and bleeding control and in both perimenopause and menopause for endometrial protection while using estrogen therapy to control bothersome menopause symptoms. The use of an IUS for endometrial protection as part of hormone therapy is off label in the United States but is approved for use in more than 100 countries for up to 5 years. Some IUSs have been approved for contraceptive use for 8 years, and questions remain whether they provide adequate endometrial protection when combined with estrogen therapy beyond 5 years of use.