I. Development of hormone replacement therapy Hormone replacement therapy (HT) refers to the exogenous administration of drugs with sex hormone activity to correct the signs and symptoms composed of sex hormone deficiency when the body lacks sex hormones. The use of HT to improve menopausal symptoms became popular in the Americas and Europe in the 1960s; the widespread use of estrogen has increased the incidence of endometrial cancer, and in 1971 the International Health Foundation emphasized the need to add progestin to estrogen supplementation in women with a uterus to protect the endometrium. The interim report of the Women’s Health Initiation Project (WHI) on continuous combined estrogen and progestin therapy in the United States in 2003 negated the primary prevention of cardiovascular disease with HT. According to the latest guidelines of the International Menopause Society, the European Menopause Society, the North American Menopause Society and the Asia Pacific Menopause Society, and taking into account the specific situation in China, the Menopause Group of the Obstetrics and Gynecology Branch of the Chinese Medical Association has formulated the Guidelines for the Clinical Application of Hormone Supplementation Therapy in the Transitional and Postmenopausal Periods (2009 edition). HT is still the most effective treatment for vasodilatory symptoms and genitourinary tract symptoms caused by estrogen deficiency. Individualized use of HRT (including the use of androgens when needed) can improve both sexual function and overall quality of life. Postmenopausal osteoporosis Based on the latest evidence on efficacy, cost and safety, HT is the appropriate first-line treatment when early menopausal and postmenopausal women are at increased risk of fracture, especially those younger than 60 years. 2. Early use is only beneficial Cardiovascular disease Cardiovascular disease is the leading cause of disease and death in postmenopausal women. The main primary prevention methods (in addition to smoking cessation and diet control) include: weight loss, blood pressure reduction, and blood glucose and lipid control. There is evidence that HT may have a protective cardiovascular effect if started around the time of menopause and continued over time (often mentioned as a “window of opportunity for estrogen supplementation”). and metabolic syndrome. HT can also reduce the risk of rectal and ovarian cancers. The use of HT around the time of menopause or in younger postmenopausal women may reduce the risk of Alzheimer’s disease. 4. Risks Breast cancer The incidence of breast cancer varies in different countries. Therefore, the available information is not necessarily generalizable. The degree of correlation between breast cancer and long-term application of hormone supplementation therapy remains controversial. Even according to the results of current large-scale studies, the possible risk of HT-related breast cancer is small (less than 0.1% per year). Some studies have shown that HT with natural estrogens for up to 7-8 years does not increase the incidence of breast cancer. Unopposed estrogen supplementation (i.e., estrogen alone, no progestin) produces dose-dependent stimulation of the endometrium. Women with a uterus require supplemental progestin use. Sequential combined estrogen and progestin therapy can result in lower rates of endometrial hyperplasia and endometrial cancer than in the general population. Thus endometrial cancer is no longer a problem to be discussed. The risk of serious venous thromboembolism associated with thromboembolism and cardiovascular events and HRT increases with age, but the risk is small until age 60.