On May 1, 2024, researchers at the National Institutes of Health (NIH) announced a review in JAMA that highlighted key findings and clinical messages from the Women’s Health Initiative (WHI), the largest women’s health study in the U.S. The WHI was created to study factors that may reduce risks for cardiovascular disease, cancer, hip fractures, and other conditions in postmenopausal women. More than 68,000 women enrolled in clinical trials between 1993 and 1998 and were followed for up to 20 years.

The WHI study found that estrogen or a combination of estrogen and progestin, two types of hormone replacement therapies, had varying outcomes with chronic conditions, and the evidence does not support the use of these therapies to reduce risks for chronic diseases, such as heart disease, stroke, cancer, and dementia. The study was not designed to assess the effects of FDA-approved hormone therapies for treating menopausal symptoms, the benefits of which had been established before the WHI study began.

The authors reinforce the importance of women making shared decisions with physicians about the benefits or risks of taking hormone therapy during menopause. For example, women younger than age 60 with low-to-average risk for cardiovascular disease and breast cancer who want to take hormone therapy may experience greater health benefits than risks during early menopause to treat moderate-to-severe symptoms, such as bothersome hot flashes or night sweats.