What is menopause?

Process and Effects

The word “menopause” comes from two Greek words meaning “month” and “cessation.” It is used medically to mean a cessation of, not a “pause” in, menstrual periods. Technically, the menopause begins the moment a woman has had her final menstrual period; until then, her menstrual periods may have shown a wide variety of irregularities, including missed periods.

Medical experts refer to the time when the body is noticeably preparing for the menopause as the perimenopause, which can begin anywhere from five to ten years before the menopause. While estrogen levels begin to decrease gradually, periods are normal but memory may be less sharp and mood swings may occur. During that time, a woman still experiences menstrual periods, but they are erratic. Some women stop menstruating suddenly, without irregularities; however, they are in the minority. For some women, signs of the menopause, such as hot flashes, may begin during the perimenopause. For even more women, such signs begin, or at least increase in intensity, at the menopause.

The term “climacteric” covers a longer span and includes all the years of diminishing estrogen production, both before and after a woman’s last menstrual period. Some experts believe that women may undergo declines in their levels of estrogen even when they are in their late twenties; almost all experts believe that estrogen levels drop at least by a woman’s mid-thirties, and the process accelerates in the late forties.

The average age at which the menopause occurs is fifty-one years, with the usual range between ages forty-five and fifty-five. For some it occurs much earlier, for others much later. Only 8 percent of women reach the menopause before age forty, and only 5 percent continue to menstruate after age fifty-three. A very few have menstrual periods until they are sixty.

Even after the menopause, the climacteric continues. Declining hormonal levels bring more changes, until the situation stabilizes. A decade or more of noticeable changes can take place before the climacteric is completed. Unlike the climacteric, the menopause itself is usually considered completed after one full year without a period. After two years, a woman can be reasonably certain that her periods have ceased permanently. The signs and symptoms of the menopause, however, can linger for years longer.

Starting in her mid-forties, a woman’s ovaries gradually lose their ability to respond to the follicle-stimulating hormone (FSH), which is released by the pituitary into the blood, triggering the release of estrogen from the ovaries. A few eggs do remain even after menstrual flows have ceased, and the production of estrogen does not stop completely after the menopause; in much smaller amounts, it continues to be released by the adrenal glands, in fatty tissue, and in the brain. At the menopause, however, the blood levels of estrogen are drastically reduced—by about 75 percent.

About two to four years before the menopause, many women stop ovulating or ovulate irregularly or only occasionally. Although almost all the follicles enclosing the eggs are depleted by this time, the ovaries continue to produce estrogen. Estrogen continues to build up the endometrium (the lining of the uterus), but without ovulation no progesterone is produced to shed the extra lining. Therefore, instead of regular periods, a woman may bleed at unexpected times as the extra lining is shed sporadically.

During the perimenopause, menstrual periods may be late or early, longer than usual or shorter, and lighter than before or heavier. They may disappear for several months, then reappear for several more. It has been noted that in 15 to 20 percent of women the typical menopausal symptoms, sometimes accompanied by noticeable mood swings similar to premenstrual tension, begin during the perimenopausal period.

According to the National Institutes of Health (NIH), about 80 percent of women experience mild or no signs of the menopause. The rest have symptoms troublesome enough to seek medical attention. The two most important factors in determining how a woman will fare are probably the rate of decline of her female hormones and the final degree of hormone depletion. A woman’s genes, general health, lifetime quality of diet, level of activity, and psychological acceptance of aging are also major influences. The most severe symptoms occur in women who lose their ovaries through surgery or radiation when they are perimenopausal.

When only the uterus is removed (hysterectomy) and the ovaries remain intact, menstrual periods stop but all other aspects of the menopause occur in the same way and at the same age. When only one ovary is removed, the menopause occurs normally. If both ovaries are removed, a complete menopause takes place abruptly, sometimes with intense effects. Women who have had a tubal ligation to prevent pregnancy will experience a normal menopause because tubal ligation does not affect ovaries, the uterus, or hormonal secretions.

Although experts disagree about the causes of a variety of symptoms that may appear at the menopause, there is no disagreement about the fact that the majority of women experience hot flashes, or flushes. For two out of three women, hot flashes can start well before the last menstruation. Generally, however, hot flashes increase dramatically at menopause and continue to occur, with intermittent breaks (sometimes lasting several months), for five years or so.

While hot flashes are not dangerous, they are uncomfortable. Many women have only three or four episodes a day—or even a week—and hardly notice them. Others have as many as fifty severe flashes a day. The intense waves of heat generally last several minutes, but some unusual flashes have been reported to last as long as an hour. Usually there is some perspiration; with a severe flash, there is heavy perspiration. Because the blood vessels dilate (expand) and then contract, the hot flash is often followed by chills, even intense shivering. Since the flashes are usually worse at night, they can cause insomnia.

Other vasomotor symptoms can also appear with the menopause. Experts believe that they are the result of disruptions of the same mechanisms—vasomotor instability—that are manifested as hot flashes. Palpitations, which are distinct and rapid heartbeats, may also occur. A woman may experience
dizziness or may feel faint or nauseated at times. She may have peculiar sensations in her arms and hands, especially her fingers. Some feel these sensations as tingling, or pins and needles, while others say that their fingers occasionally feel
numb. One of the oddest, most frightening sensations associated with the menopause is formication, a feeling of insects crawling over the skin.

Headaches, depression, mood swings, insomnia, and weight gain often affect women at the menopause and may be related to the body’s hormonal readjustments. Insomnia is second only to hot flashes as the symptom that causes women to seek out their doctors’ help at the menopause. The hypothalamus controls sleep as well as temperature and hormone production;
insomnia is caused by changes in sleep patterns and brain waves from the same hypothalamic disturbances that result in the hot flashes and an overstimulated central nervous system.

Complications and Disorders

During the menopause, the walls of the vagina become smooth and dry and produce less lubrication, producing a condition called atrophic vaginitis. It has been assumed that this condition is attributable to a lack of estrogen. Despite doubts concerning the relationship between circulating estrogen and objective measures of vaginal atrophy, estrogen (often topical) is frequently prescribed and effectively used in the alleviation or elimination of symptoms.

One of the problems that women encounter with the menopause is
calcium deficiency. Many experts believe that before the menopause a woman requires a minimum of 1,000 milligrams of calcium a day in food or supplements. At the menopause, however, a woman who is not taking estrogen needs 1,500 milligrams of calcium a day. Since it is very difficult to obtain these daily allotments from food without consuming considerable amounts of milk or milk products, calcium supplements are often recommended for menopausal and postmenopausal women.

If the calcium deficiency is allowed to persist, osteoporosis, a loss of bone density that can lead to dangerous fractures, can result. Osteoporosis is known to have less of a damaging effect on women who are somewhat overweight because estrogen continues to be produced in fatty tissues after the menopause. Cigarettes, alcohol, and caffeine increase bone loss because they interfere with the body’s ability to absorb calcium. A well-balanced diet, calcium supplements, and regular exercise—especially weight-bearing exercise—are effective ways of controlling osteoporosis. Hormone therapy is another means of coping with osteoporosis brought on by the menopause. Since nearly half of all women do not develop osteoporosis, however, many physicians do not believe that administering estrogen therapy to combat this disease is worth the risks, except in women at high risk for osteoporosis.

Although estrogen was isolated as a substance in the 1920s, the modern study of hormones—how they work, where they are produced, and what their benefits are—began in the 1940s. Originally, estrogen was administered cautiously to women who had lost their ovaries through surgery and to those with severe distress after the menopause. It was not until the 1960s that estrogen replacement therapy became widespread, however, when books such as Robert A. Wilson’s Feminine Forever (1966) promoted its use as the newfound “fountain of youth” for women. The replacement of estrogen was suddenly fashionable, with the hormone being viewed as a miracle drug that could keep women looking and feeling youthful well into their later years. Physicians began prescribing it for women well before the menopause, and it was recommended for use throughout life. Often, large doses were prescribed.

By the mid-1970s, millions of women were taking estrogen. A decade later, however, the numbers had fallen. Beginning in 1975, research studies began documenting dramatic increases—sometimes as high as 500 percent—in cases of cancer of the lining of the endometrium among women taking estrogen, compared with those not taking it. Other studies at that time found higher rates of breast cancer as well as other problems, such as gallbladder conditions, among women taking estrogen.

Some studies found the overall risk of contracting uterine cancer increased 350 percent for women who took estrogen for a year or more. Some women who were on the therapy for long periods were judged to be as much as 100 percent more likely to contract uterine cancer. Furthermore, contrary to expectations, some studies claimed that the risk persisted even ten years after the estrogen use was discontinued. Other studies also found that the risk of cancer persisted, though for a shorter period.

These studies were based on replacement therapy using estrogen only. Estrogen stimulates the growth of cells in the endometrium, which is one of the aspects of the development of cancer. Consequently, a treatment was developed in which estrogen was combined with a form of progesterone in an effort to reduce the risk of uterine cancer and other diseases. Today, the most widely used regimen calls for estrogen in the lowest effective dose. A form of progesterone called progestin is added to this therapy, and then both hormones are stopped. Uterine bleeding, similar to that of a menstrual period, may occur, allowing the progesterone to break down any excess buildup of cells in the endometrium.

In the past, a number of women were given hormone therapy to alleviate menopausal symptoms, and they may have received longer-term therapy with the intention of preventing cardiac disease and osteoporosis. Some clinicians prescribed estrogen therapy for women with severe symptoms after a surgical menopause.

In the early twenty-first century, however, the use of hormone therapy—either long-term or short-term—was questioned. A study called the Women’s Health Initiative, funded by the NIH, compared thousands of women who took combination hormone therapy to women who were given placebos. Those on the combination treatment had an increased risk for heart disease, stroke, and blood clots in the lungs. As a result, organizations such as the American Heart Association, the American College of Obstetricians and Gynecologists, and the North American Menopause Society recommended that combination therapy not be used for the prevention of cardiac disease, osteoporosis, or dementia. Today, combination hormone therapy is offered only to women with vasomotor symptoms (hot flashes and associated discomforts) that are severe enough to negatively impact life, and dosages are intended to be the lowest possible dose for the shortest period of time. Other drugs can be used to prevent or treat osteoporosis, drugs such as bisphosphonates and estrogen agonists/antagonists, which do not carry the same risks as hormone therapy.

Anecdotal evidence and some research studies suggest that stress reduction and exercise can relieve some of the symptoms of the menopause, including hot flashes and mood swings. In addition, a host of herbal remedies on the market claim to improve menopausal symptoms, although caution should be used in choosing these products. A double-blind pilot study of women using soy as a natural estrogen replacement therapy turned out positive; hot flashes decreased significantly in women taking soy powder for six weeks. The isoflavones in soy are chemically similar to estrogens. However, other studies involving the effects of soy have been inconsistent. Vitamin E, which is structurally similar to estrogen at the molecular level, decreases hot flashes in some women. Evidence of this is anecdotal, however, as no large studies have been conducted that prove the claim. Black cohosh is the best documented of all the herbal remedies. Studies suggest that it can relieve menopause-related headaches, depression, anxiety, hot flashes, night sweats, heart palpitations, and vaginal dryness and thinning. Black cohosh suppresses the secretion of luteinizing hormone, a hormone that is believed to be at the root of many menopausal symptoms. One European study of eighty women found that black cohosh relieved menopausal symptoms more effectively than estrogen replacement therapy. Other studies had mixed results.

Perspective and Prospects

The menopause, in various guises, was referred to in many early cultures and texts. Initially, an association was made between age and the loss of fertility. By the sixth century, written records on the cessation of
menstruation were well documented. At that time, it was believed that menstruation does not cease before the age of thirty-five, nor does it usually continue after the age of fifty. It was thought that obese women cease menstruation very early and that periods remain normal or abnormal and increase in flow or become diminished depending on age, the season of the year, the habits and peculiar traits of women, the types of food eaten, and complicating diseases. Similar descriptions of menstrual cessation and its age of onset continued for another thousand years. It was not until the late eighteenth and early nineteenth centuries, however, that much advancement in the knowledge of the topic took place.

John Leake, influenced by William Harvey’s historic description of the circulatory system, made one of the first reasonable attempts to explain the etiology of the menopause in his 1777 book Medical Instructions Towards the Prevention and Cure of Chronic or Slow Diseases Peculiar to Women. He believed that as long as the “prime of life” continues, along with the circulating force of the blood being more than equal to the resistance of the uterine vessels, the menses will continue to flow. When these vessels become firm from the effect of age, however, the diminished current of blood is insufficient to force the uterine vessels open, and then periodic discharge will cease.

A later development in the history of menstruation studies was to link menstruation with all sorts of other problems, both emotional and organic. In Leake's work he comments that at the time of cessation of menses, women are often afflicted by various chronic diseases. He adds that some women are prone to pain and light-headedness, others are plagued by an intolerable itching at the neck of the bladder, and some are affected by low spirits and melancholy. Leake thought, because it seemed extraordinary that so many disorders should result from such a natural occurrence in a woman’s life, that these symptoms can be explained away by indulgence in excesses, luxury, and an “irregularity” in the passions. Laying the blame for complications with the menopause on societal (in particular, female) excesses continued for some time.

Specific disease associations were also made; in 1814, John Burns announced that the cessation of menses seems to cause cancer of the breast in some women. Edward John Tilt, a British physician, wrote one of the first full-length books on The Change of Life in Health and Disease (1857). Some of his views were that women should adhere to a strict code of hygiene during menstruation because they are often afflicted with cancer, gout, rheumatism, and nervous disorders.

These beliefs reflect a tendency from the mid-nineteenth century onward for medical literature to associate the menopause with many negative sociological features. For example, Colombat de l’Isère, in his book Traité des maladies des femmes et de l’hygiène spéciale de leur sexe (1838; A Treatise on the Diseases and Special Hygiene of Females, 1845), expresses his belief that during the menopause women cease to live for the species and live only for themselves. He thought it prudent for men to avoid having erotic thoughts about women in whom these feelings ought to be extinct; he believed that after the menopause sexual enjoyment for women is ended forever.

Not all physicians, however, took such a negative attitude. Some believed that examining this phase in a woman’s life presents a challenge. They believed that the boundaries between the physiological and the pathological in this field of study are ill-defined and that it is in the interest of the male gender to conduct more research into this stage of a woman’s life. The narrow boundary between normal physiology and pathology was still not fully defined nearly a hundred years later, nor did the many negative and unsubstantiated theories cease. Well into the 1960s, the menopause was still considered “abnormal” and a “negative” state by some physicians.

Three major milestones exist in the history of menopause research in the twentieth century. The first event was the achievement of Adolf Butenandt, who won the Nobel Prize in Chemistry. He succeeded in 1929 in isolating and obtaining, in pure form, a hormone from the urine of pregnant women that was eventually called estrone. The second development was the publication of Feminine Forever in 1966, which became an instant best seller. As a result of the book’s publication, physicians were prompted to take sides in a heated and continuing debate. The third landmark was the publication of an editorial and two original articles in The New England Journal of Medicine of December 4, 1975, claiming an association between exogenous estrogens and endometrial cancer. This claim brought about legal action by initiating, at least in the United States, a series of health administration inquiries.

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