Lessons Learned from the Women's Health Initiative Trials of Menopausal Hormone Therapy

We re-evaluate the Women's Health Initiative findings and their implications for clinical practice. Menopausal hormone therapy (HT) was effective for relief of vasomotor symptoms, and the risk of coronary heart disease (CHD) tended to be reduced in women close to menopause compared with the increased risk in women more distant from menopause. In recently menopausal women, short-term absolute risks of stroke and venous thromboembolism were small. Estrogen plus progestin therapy, but not estrogen therapy, increased the risk of breast cancer with a suggestion of greater risk when initiated close to the menopause. Menopausal HT increased the risk of CHD in women more than 20 years distant from menopause, particularly in women with vasomotor symptoms. It remains unknown whether the suggestive benefit for CHD in younger women will translate into benefits or harms if menopausal HT is continued into older ages. Based on Women's Health Initiative data, the use of menopausal HT for fewer than 5 years is a reasonable option for the relief of moderate to severe vasomotor symptoms. The risks seen with estrogen plus progestin therapy suggest careful periodic reassessment of the ongoing therapy needs for women taking estrogen plus progestin therapy. The more favorable profile of estrogen therapy allows for individualized management with respect to duration of use when symptoms persist. For both estrogen therapy and estrogen plus progestin therapy, the baseline risk profile of the individual woman needs to be taken into account. Menopausal HT is not suitable for long-term prevention of CHD given risks of stroke, venous thromboembolism, and breast cancer (for estrogen plus progestin therapy) found in both clinical trials and in observational studies.