Grant: Operating Grant

Perimenopausal hot flushes affect an estimated 2 million Canadian women and 200 000 experience severe symptoms that strongly disturb sleep and quality of life. Although hot flushes and night sweats begin in perimenopause (the transition to menopause) almost all therapies have only been tested with menopausal women. Therapies that work in menopause, when estrogen and progesterone levels are low, may not work in perimenopause, when estrogen levels are variable and elevated (25% above earlier reproductive years) with lower progesterone levels. Neither estrogen (the strongest medicine in menopause) nor birth control pills have been proven helpful for perimenopausal hot flushes. We believe that progesterone will improve perimenopausal hot flushes. We have found that a synthetic cousin of progesterone (medroxyprogesterone) is as good as estrogen in menopause. We also believe that progesterone is safe because when given without estrogen it does not increase the risk of blood clots or breast cancer. In clinical experience, when we have given progesterone to perimenopausal women, they had fewer and less intense hot flushes. Our recent study showed that natural progesterone as a pill (Prometrium) is effective for menopausal flushes; we want to test it in perimenopause. The purpose of this 4-year study is to compare the frequency and intensity of hot flushes over three months for women taking Prometrium daily at bedtime with women taking identical inactive capsules. We will randomize 175 women to active or placebo therapy. During the study, neither investigators nor the participants will know who is taking what. Each participant will record hot flushes daily for 1 month before the 3 months' treatment. This study is important because currently a large number of perimenopausal women with intense night sweats are having trouble doing their jobs and enjoying life. If natural progesterone is effective for hot flushes, perimenopausal women's health will improve.