Menopause is a natural and irreversible part of a woman’s aging process, specifically affecting her reproductive function. By definition, it is the last menstrual cycle, confirmed after 12 months of absence of menstruation in the absence of a pathological reason for this. The period is associated with numerous symptoms, which include, in addition to the change in monthly menstrual cycles, also vasomotor and urogenital symptoms, such as vaginal dryness and dyspareunia (painful intercourse), disturbed sleep, hot flashes, increased nervousness, mood changes and etc. The described complaints are observed even in the so-called perimenopausal period, which covers the period of transition from normal ovulatory function to menopause. It starts on average about 2 years before menopause and also includes the 12 months after it. The average age at which menopause naturally occurs is 51. Menopause of a natural nature or as a result of an external influence (surgery or radiation therapy) before 45 years is early menopause. Premature menopause is one that occurs before the age of 40. Menopause results from a loss of ovarian sensitivity to the action of gonadotropins, which is directly related to follicular depletion. Gonadotropins are hormones synthesized by the pituitary gland – luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Ovaries are mainly made up of stroma and follicles. Ovarian hormone synthesis of estrogens, progesterone and androgens takes place in the stroma. A group of follicles mature monthly, with one of them eventually becoming a mature egg, aided by the other maturing follicles. Egg cells in the ovaries undergo atresia throughout a woman’s life as a result of a decline in the quantity and quality of follicles. The change in menstrual cycle length in postmenopausal women is primarily due to a reduction in the pool of maturing monthly follicles rather than follicular failure. With the entry into the perimenopausal period, anovulatory cycles (without ovulation occurring) and months with irregular bleeding become more frequent. The reasons for this are a variable response of the ovaries to stimulation by gonadotropins, estrogen insensitivity and lack of a peak in the secretion of luteinizing hormone, which mediates ovulation itself. Fluctuation in hormonal secretion may not be the only cause of irregular bleeding. That is why other causes such as uterine polyps, endometrial hyperplasia or endometrial tumor should be ruled out. NEWS_MORE_BOX With the passage of time and the “aging” of the follicles, they become more and more resistant to the action of gonadotropins, which is why their levels rise. The level of the follicle-stimulating hormone increases primarily, as the reason for this is the reduced synthesis by the “aging” follicles of a hormone synthesized by them – inhibin B. The increase in the levels of the follicle-stimulating hormone succeeds in increasing the levels of estrogens,which persists until about a year before the onset of menopause, when they drop sharply. About 3 years after the onset of menopause, the level of circulating estrogens is permanently low. The main circulating estrogen is estrone. In the absence of follicles, the majority of circulating estrogens are provided after aromatization to estrone of androstenedione synthesized in the ovarian stroma and adrenal glands. Postmenopausal progesterone is of adrenal origin. DHEAS and DHEA levels also fall, although they are produced primarily in the adrenal glands. Total testosterone levels do not change after menopause. The ovaries retain their function to secrete significant amounts of testosterone even after menopause. The conversion of androgens to estrogens in the ovarian stroma and in peripheral tissues determines the importance of the postmenopausal ovary in the woman’s homeostasis. That is why prophylactic removal of the ovaries during operations on another occasion is not recommended and should be avoided!
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