menopause

/men"euh pawz'/, n. Physiol.

1. the period of permanent cessation of menstruation, usually occurring between the ages of 45 and 55.

2. See male menopause.

[1870-75; < F ménopause. See MENO-, PAUSE]

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Final cessation of menstruation, ending female fertility.

It usually begins between ages 45 and 55. A gradual decline in function of the ovaries reduces estrogen production. Ovulation becomes irregular and gradually ceases. The length of the menstrual cycle and periods may vary; flow may lessen or increase. Adjustment of the endocrine system to estrogen reduction causes hot flashes, often at night, with a warm sensation, flushing, and sweating; other symptoms, such as irritability and headaches, may be related more to reactions to aging. Removal or destruction of the ovaries to treat disease causes artificial menopause, with similar but more sudden effects. Changes in hormone balance usually cause no physical or mental disturbances. However, the protective effect of estrogen against osteoporosis and atherosclerosis is lost, and risks of fracture and coronary heart disease increase.

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      final cessation of menstruation and therefore the end of a woman's reproductive life. The popular term “change of life” is neither descriptive nor accurate, for it tends to indicate a physical, mental, and sexual deterioration, whereas deterioration does not occur.

      In most women, menopause begins between the ages of 45 and 55 years. Although the average age for onset is about 50 years, menopause may begin as early as age 40 or be delayed to the late 50s. Although the age of onset is probably determined by the hereditary background of the individual, good nutrition and health habits tend to postpone onset. A premature menopause—i.e., one that takes place spontaneously before the age of 40—occurs in about 8 percent of women. An artificial menopause may be induced by removing the ovaries (ovary) by surgery or by destroying them with X rays or radium.

      The natural life of the ovaries is about 35 years. The menopause is brought on by a progressive decline in ovarian function. This decline is a normal result of aging (human aging) and is accelerated as the menopause approaches. During the reproductive years follicles in the ovaries mature and release their ova periodically under hypothalamic-pituitary stimulation. In the years immediately preceding the menopause, however, first some follicles and later all follicles fail to rupture and release their ova. The failure to ovulate results in a disturbed menstrual pattern. A woman may miss a period or two and suspect pregnancy. A medical examination, however, will establish the proper diagnosis. The continued decline in ovarian activity may provoke prolonged intervals between periods or irregular bleeding episodes. The length of the periods may vary, and the flow may become either more scant or profuse. In a fortunate small minority the periods cease abruptly.

      As the ovaries decline in function, they produce smaller and smaller amounts of the hormone estrogen; (estrogen) this decline in estrogen initiates subtle rearrangements in the hormonal activity of the glands that control the reproductive function. The decrease in output of estrogen disturbs the neurovascular mechanism of the hypothalamus and probably initiates the vasomotor changes that may provoke the characteristic “hot flashes” of the menopause. The metabolism of the pituitary gland is altered and increasing amounts of follicle stimulating hormone (FSH) appear in the blood and urine. Rearrangements in the hormonal activity of the adrenal and thyroid glands also take place, for the metabolic activities of all these glands are interrelated. These adjustments are usually made without physical or mental disturbances in most women.

      Hot flashes are the only characteristic symptoms of the menopause. They often appear before its obvious onset and their duration is usually limited to two or three years. The young woman who has her ovaries removed for disease or other reasons will develop flashes within a week following the operation.

      The hot flash usually begins as a sense of warmth over the upper chest. It then spreads to the neck and face and may extend over the entire body, sometimes giving rise to a prickling sensation. The woman is acutely aware of blushing, which usually is disturbing to her, particularly in company. The flashes may recur frequently during the night and may interfere with sleep. She may awaken because of a chilly sensation and may perspire freely.

      A variety of other symptoms can and do occur, although many are entirely unrelated to the changes incidental to the menopause. Nervousness, headaches, and dizziness are common complaints. The fear of aging, the altered pattern of life, and changing family relationships also may precipitate many disturbing symptoms.

      Many women complain of weight gain during the menopause. Occasionally this is related to decreased thyroid function. In most cases, however, it is brought about by decreased physical activity and by increased food intake. The menopause is not necessarily associated with unusual changes in physical appearance and fitness.

      The administration of estrogenic hormones—once a widely approved remedy for relief of menopausal symptoms and also believed to retard the development of atherosclerosis and osteoporosis (bone decalcification)—has been associated with increased incidence of endometrial cancer and is being reevaluated.

M. Edward Davis Ed.

Additional Reading

Information on menopause may be found in Linda R. Gannon, Menstrual Disorders and Menopause: Biological, Psychological, and Cultural Research (1985); and Herbert J. Buchsbaum (ed.), The Menopause (1983). Ed.

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