Postmenopausal women who have had a hysterectomy should not take estrogen replacementtherapy (ERT) to prevent osteoporosis, stroke, or heart disease, according to new guidelinesfrom the US Preventive Services Task Force. The recommendation was based on evidencefrom the ongoing Women's Health Initiative clinical trial, along with other studies. Although estrogenhas positive effects, regular use of ERT may increase the risk of potentially fatal blood clots,stroke, dementia, and mild cognitive impairment. The task force stated that any benefits of ERTare outweighed by these harmful effects. The group encourages women to discuss other optionsfor preventing bone fractures, cancer, or heart disease with their doctors.