The Women’s Health Initiative (WHI) comprised a series of clinical studies initiated in 1991 by the National Institutes of Health, specifically focused on postmenopausal health issues causing morbidity or mortality. The 2002 study addressed menopause hormone therapy (MHT) and its impact on the prevalent issue of heart disease, as well as stroke, certain cancers, and other fatal health concerns. Its outcomes indicated a potentially increased risk of breast cancer, heart disease, and pulmonary embolism, overall concluding that the risks of MHT outweigh the benefits. This led to widespread media attention and a sharp decline in the prescription of the treatment for patients.

From Dr. Mary Claire Haver’s perspective, this study created a legacy of fear that continues to influence medical practice. Though subsequent analysis clarified the study’s flaws, a significant evidence-to-practice lag, often lasting 17 years, has kept outdated caution in place. A corrective shift occurred with The North American Menopause Society’s 2022 position statement, which affirmed, “The safety profile of hormone therapy is most favorable when initiated in healthy women aged younger than 60 years or within 10 years of menopause onset” (Faubion, Stephanie S., et al. “The 2022 Hormone Therapy Position Statement of The North American Menopause Society.” Menopause, vol. 29, no. 7, 2022, pp. 767-94). This guidance establishes a clear window where benefits often outweigh risks. However, Haver highlights how frequently medical research can suffer from slow integration in practice.

In The New Perimenopause, Haver argues that this historical misstep created the current undertreated status quo, and she spends much of the text demonstrating MHT’s benefits across different health concerns—physical and cognitive—for perimenopausal and menopausal patients. She describes how the WHI fallout “wiped out any progress that had been made up to that point in the treatment of women in their post-reproductive era” (xvii). This created a persistent clinical vacuum of outdated guidelines, such as the American College of Obstetricians and Gynecologists’ 2014 standards, leading clinicians to overlook perimenopausal needs. The downstream effects include missed MHT discussions and the reflexive prescription of antidepressants for hormonally driven symptoms.