The number of follicles in a woman's ovaries is fixed from birth. From birth to adolescence, the follicles begin to develop, and ovulation occurs each month. Once all the follicles are depleted, ovarian function declines, leading to menopause. When a woman experiences menopause after the age of 40, it is considered a normal occurrence, and estrogen replacement therapy can be used at this time. However, a physical examination must be conducted before using these medications, as they are not suitable for everyone. If menopausal symptoms are particularly severe, sequential estrogen therapy can be applied, which may result in the return of menstrual periods, but this does not indicate a recovery of ovarian function; it is due to the medication. If the symptoms during menopause are not very severe, observational treatment may also be considered.