When women initiate estrogen therapy matters

(Press-News.org) CLEVELAND, Ohio (Oct 21, 2025)—Menopause may take a toll on women physically and emotionally due to declining estrogen levels. For some, the use of hormone therapy has proven valuable in managing bothersome menopause symptoms. A new study suggests that when a woman starts taking hormones makes a major difference in longer term health outcomes. Results of the study will be presented at the 2025 Annual Meeting of The Menopause Society in Orlando October 21-25.

A large percentage of women will experience some type of menopause symptoms, with the most common symptom being hot flashes. Many women will actually start to experience menopause symptoms during perimenopause, the transitional period before the final menstrual period. Perimenopause can last for years, during which time a woman’s estrogen levels fluctuate and decline.

Estrogen therapy has been shown to be one of the most effective and generally safe means for managing bothersome menopause symptoms. However, there is a lack of data regarding the impact of initiating hormone therapy in perimenopause in terms of longer-term health outcomes. A new retrospective cohort analysis based on data from more than 120 million patient records aimed to compare the impact of estrogen therapy when started during perimenopause or after menopause or not at all. Specifically, the study looked at breast cancer, heart attack and stroke risk associated with estrogen therapy.

The findings revealed that perimenopausal women who had used estrogen for at least 10 years prior to menopause had significantly lower odds of developing breast cancer, heart attack and stroke compared to the other two groups—approximately 60% lower. Women who started estrogen therapy after menopause had slightly lower odds of breast cancer and heart attack than those women who never took hormones. However, these women had a 4.9% higher likelihood of experiencing a stroke than the non-estrogen therapy group.

These findings highlight the potential benefit of earlier initiation of estrogen therapy during perimenopause for minimizing risk and optimizing long-term health outcomes. More detailed results will be discussed at the 2025 Annual Meeting of The Menopause Society as part of the poster presentation entitled “The Timing of Estrogen Therapy: Perimenopausal Benefits and Postmenopausal Risks.”

“There has long been a debate about if and when estrogen therapy should begin, so hopefully the use of large-scale electronic health record data will help resolve that question,” says Ify Chidi, lead author from Case Western Reserve University School of Medicine in Cleveland. “The goal of this study was to explore whether estrogen therapy could do more than relieve symptoms, and the results suggest that early initiation could be a key factor in reducing morbidity. Hopefully, these results start a larger conversation about prevention in women’s health. If we can better understand the effect of hormones throughout menopause, we can improve the quality of life and reduce disease burden.”

Further clinical research is needed to confirm these results and to explore the long-term effects of estrogen therapy at different stages of menopause.

“The findings of this study suggest lower risk and potentially greater benefit of estrogen-based therapy when started in perimenopause. While the observational study design is subject to known potential biases such as healthy user bias, these results may pave the way for additional research on the risks and benefits of hormone therapy when initiated earlier in the menopause transition,” says Dr. Stephanie Faubion, medical director for The Menopause Society.

Both Ms. Chidi and Dr. Faubion are available for interviews prior to the Annual Meeting.

For more information about menopause and healthy aging, visit menopause.org.

The Menopause Society is dedicated to empowering healthcare professionals and providing them with the tools and resources to improve the health of women during the menopause transition and beyond. As the leading authority on menopause since 1989, the nonprofit, multidisciplinary organization serves as the independent, evidence-based resource for healthcare professionals, researchers, the media, and the public and leads the conversation about improving women’s health and healthcare experiences. To learn more, visit menopause.org.

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