Postmenopause: The physiological period following the MENOPAUSE, the permanent cessation of the menstrual life.Perimenopause: The transitional period before and after MENOPAUSE. Perimenopausal symptoms are associated with irregular MENSTRUAL CYCLE and widely fluctuated hormone levels. They may appear 6 years before menopause and subside 2 to 5 years after menopause.Menopause: The last menstrual period. Permanent cessation of menses (MENSTRUATION) is usually defined after 6 to 12 months of AMENORRHEA in a woman over 45 years of age. In the United States, menopause generally occurs in women between 48 and 55 years of age.Hot Flashes: A sudden, temporary sensation of heat predominantly experienced by some women during MENOPAUSE. (Random House Unabridged Dictionary, 2d ed)Premenopause: The period before MENOPAUSE. In premenopausal women, the climacteric transition from full sexual maturity to cessation of ovarian cycle takes place between the age of late thirty and early fifty.Estrogen Replacement Therapy: The use of hormonal agents with estrogen-like activity in postmenopausal or other estrogen-deficient women to alleviate effects of hormone deficiency, such as vasomotor symptoms, DYSPAREUNIA, and progressive development of OSTEOPOROSIS. This may also include the use of progestational agents in combination therapy.Women's Health: The concept covering the physical and mental conditions of women.Follicle Stimulating Hormone: A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and LEYDIG CELLS. FSH consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.