Bayer registers real-world study of Mirena for endometrial protection during estrogen therapy

Bayer registered an observational study using U.S. health insurance claims data to examine endometrial protection practices in women on estrogen therapy.

• SHIELD-ET (NCT07795606) is an observational study sponsored by Bayer that will look at women aged 40 years and older who have a uterus and started estrogen therapy.¹ The study has a listed start date of 2026-08-31 and is now active, not recruiting. Data will come from two U.S. health insurance claims databases, Optum Clinformatics Data Mart and MarketScan Commercial Claims and Encounters Database, with an estimated enrollment of 456,000 participants.¹ Researchers will describe how often women use estrogen alone, estrogen with Mirena, or estrogen with other progestogen treatments over the past 10 years, and will track rates of endometrial hyperplasia, endometrial cancer, abnormal or heavy bleeding, and hysterectomy among these groups.¹ The study's estimated primary completion date is 2026-10-30.