
Over the years, experts have taken a look back at the original WHI study to address these misinterpretations.
What the findings actually showed was that estrogen therapy alone reduced breast cancer risk by 23% and breast cancer death by 40%. Although there was a slight increased risk of breast cancer associated with combined synthetic estrogen and progestin HRT, breast cancer death risk did not increase. Researchers from the WHI have since acknowledged that estrogen therapy reduces the risk of breast cancer.(2)(4)
Although hormone-sensitive cancers are considered a contraindication for HT, new research suggests that not every form of menopause hormone therapy may be off limits for women with a history of breast cancer. A 2025 study published in the American Journal of Obstetrics and Gynecology showed that low-dose vaginal estrogen use among breast cancer survivors was not associated with an increased risk of recurrence, death from breast cancer, or overall mortality.(5)
Researchers have also found that the increased risk of coronary heart disease reported in the original WHI study was not statistically significant, meaning the evidence was so weak that it could have occurred by chance. The form of menopausal HT also matters, as transdermal HT is not associated with cardiovascular risks in the same way oral HT is. In fact, current research demonstrates that hormone therapy may protect women’s heart health later in life.(2)
Current research shows that HT may reduce the risk of additional health conditions that commonly affect postmenopausal women later in life. This includes osteoporosis, cardiovascular disease, cognitive decline, fatty liver disease, and type 2 diabetes.(6)(7)
For most healthy women with no treatment contraindications, the Menopause Society states that the benefits of HT for menopause generally outweigh the risks when treatment is started before the age of 60 or within ten years of the final menstrual period.(1)