Menopause
Menopause is the transition between a woman's childbearing years and her non childbearing years. For most women, menopause is the last stage of a gradual biological process that actually begins during their mid-thirties.
Menopause is considered complete when a woman has stopped menstruating, or having her period, for 1 year. This usually occurs between ages 45 and 55, with variations in timing from woman to woman. By the time natural menopause is complete, hormone output has decreased significantly, but does not completely stop. Women who have surgery to remove their ovaries (an operation called bilateral oophorectomy) experience "surgical menopause," the immediate cessation of ovarian hormone production and menstruation. Doctors may recommend hormone replacement therapy (HRT), using either estrogen alone or estrogen in combination with progestin (a form of progesterone) to counter some of the possible effects of natural or surgical menopause on a woman's health and quality of life.
Because of advances in medical care and fewer deaths during childbirth, the average life expectancy for women in the United States has increased from approximately 62 years to about 80 years since the beginning of this century. A 50-year-old woman today can expect to live at least one-third of her life after menopause. About 35 to 40 million women are currently going through or are past menopause. The "baby boomer" generation is expected to add another 20 million to that total in the next decade, greatly increasing the number of women who will need to weigh the benefits and risks of HRT.
While menopause is defined by many people as simply the end of a woman's menstrual cycles and her ability to bear children, it is also the beginning of a new and distinct phase of her life, with its own special health issues.
Symptoms of Menopause
Each woman experiences menopause differently. Some women have minimal discomfort, while others have moderate or even severe problems. Hot flashes, the most common symptom, occur in more than 60 percent of menopausal women. Hot flashes often begin several years before other symptoms of menopause occur.
Other changes involve the vagina and urinary tract. Declining estrogen levels can make vaginal tissue drier, thinner, and less elastic, which can make sexual intercourse painful. Urinary tract tissue also becomes less elastic, sometimes leading to involuntary loss of urine upon coughing, laughing, sneezing, exercising, or sudden exertion (stress incontinence). Urinary tract infections tend to occur more frequently. Other possible effects of menopause include sleep disturbances, mood swings, depression, and anxiety.
Health Effects of Menopause
In addition to producing some potentially uncomfortable symptoms, menopause can have more serious, long-term consequences on a woman's overall health and potential years of life. For example, the drop in estrogen that occurs at menopause is thought to cause adverse changes in levels of cholesterol and other blood lipids (fats), and in levels of fibrinogen (a substance that affects blood clotting). These changes may increase the risk of heart disease, the leading cause of death among American women, and stroke. About 370,000 women in this country die each year from heart disease, and nearly 93,000 die from stroke.
Osteoporosis (thinning of the bones) is another serious concern of later life whose effects are aggravated by menopause. Menopause speeds up the bone depletion that occurs during normal aging processes. About 25 percent of women gradually experience bone fragility and fractures as their estrogen levels decline. A decrease in bone mass may lead to curvature of the spine, fractures of the vertebrae, loss of height, and pain. Hip fractures are a common injury in women with osteoporosis that usually require a long recovery period; up to one-fourth of those who do recover need to enter a long-term care facility.
Hormone Replacement Therapy
Most women will eventually need to make decisions about whether to take HRT and, if so, for how long. Hormone replacement therapy can have beneficial effects for many women. However, there are also some concerns associated with it, and each woman needs to take both aspects into consideration when making her decisions.
Benefits of HRT
It has been well documented for several decades that HRT is the most effective remedy for the hot flashes and sleep disturbances that often accompany menopause. Hormone replacement therapy has also consistently been shown to decrease vaginal discomfort by increasing the thickness, elasticity, and lubricating ability of vaginal tissue. Urinary tract tissue also becomes thicker and more elastic, reducing the incidence of stress incontinence and urinary tract infections.
Some women and their doctors report that HRT can be helpful in relieving the depression and mood swings that may occur during menopause and can produce a general sense of well-being and increased energy. Also, some find that HRT increases skin thickness and elasticity, decreasing the appearance of wrinkles.
While HRT was used initially to reduce the discomfort from short-term menopausal symptoms, recent studies provide evidence that it may also reduce some of the negative long-term health effects of menopause. Scientists are continuing to gather information to define the potential benefits from HRT and to identify the women for whom it may be most useful. Further research will also be needed to show when HRT should be started and how long it should be continued to achieve the greatest benefits.
Hormone replacement therapy has a significant role in preventing osteoporosis by building and maintaining bone; it is also used to treat bone loss that has already begun. Hormone replacement therapy can prevent the decline of bone density and may reduce the incidence of hip fractures. Some research suggests that the greatest benefit is likely to be obtained during the first several years following menopause; in other studies, estrogen appears to be effective in suppressing bone loss even when started well past menopause. It has been shown, however, that bone loss resumes upon discontinuation of HRT.
Research shows that HRT improves blood lipids and lowers fibrinogen levels. Some studies suggest that HRT may reduce the risk of heart disease and stroke. However, scientists are concerned that some of the apparent benefits of HRT in these studies may be due to the fact that healthier or more health-conscious women may be more likely to take replacement hormones. Research is in progress to clarify this issue.
Preliminary studies suggest that taking estrogen may reduce the risk of developing Alzheimer's disease. However, scientists caution that additional research will be needed to explore this possibility.
Concerns About HRT
While HRT has potential benefits for many menopausal and postmenopausal women, it also can have drawbacks. Concerns about HRT center on the risk of endometrial cancer and breast cancer, especially after long-term use (more than 10 years).
When estrogen therapy became available for menopausal women in the 1940s, it was administered in high doses without progestin. As it became more popular in the 1960s, it was given to increasing numbers of women. In the 1970s, however, it became clear that women who received estrogen alone had up to a six to eightfold increased risk of developing cancer of the endometrium (lining of the uterus).
Now, most doctors prescribe HRT that includes progestin, along with much lower doses of estrogen, for women who have not had a hysterectomy (surgery to remove the uterus). Progestin counteracts estrogen's negative effect on the uterus by preventing the overgrowth of the endometrial lining. Adding progestin to HRT substantially reduces the increased risk of endometrial cancer associated with taking estrogen alone. A woman who has had a hysterectomy does not need progestin and can receive HRT with estrogen alone.
Because reports have shown that estrogen increases the risk of developing endometrial cancer, many women and their doctors are also concerned that HRT may increase the risk of recurrence in women with a history of endometrial cancer. At present, however, there is no scientific evidence that taking estrogen increases this risk. To help resolve this issue, the National Cancer Institute (NCI) is sponsoring a 5-year clinical study to determine the effects of estrogen in women treated for early stage endometrial cancer. The study will compare recurrence rates between women who are given estrogen and those who are not given estrogen.
The relationship between HRT and breast cancer is not clear. The possible increased risk of developing breast cancer is consistently cited by menopausal and postmenopausal women as the main reason they are reluctant to use HRT. Many women and their doctors have particular concerns about the effects of long-term HRT use on breast cancer risk.
One of the most important risk factors for developing breast cancer is a woman's lifelong exposure to naturally occurring hormones; the longer her body produces hormones, the more likely she is to develop breast cancer. Factors such as early menstruation (before age 12) and late menopause (after age 55) can contribute to prolonged hormonal exposure. Because of this relationship between prolonged hormonal exposure and breast cancer risk, scientists have been concerned that if a woman increases her lifelong hormonal exposure by taking HRT, there would be similar adverse risk.
Over the last 25 years, more than 50 studies have examined the possible relationship between HRT and breast cancer. These studies have varied widely in terms of study design; size of populations studied; and doses, timing, and types of hormones used; and they have produced inconsistent results. Some of the early studies that followed women who used high doses of estrogen alone showed increased breast cancer risk. More recent studies have looked at the experience of women who took estrogen combined with progestin. Some have shown an increased risk, while others have not.
There is also considerable uncertainty about the relationship between a woman's risk of developing breast cancer and the length of time she receives HRT. The fact that the protective effects against osteoporosis (and possibly against heart disease) diminish rapidly within several years after discontinuing therapy is of particular concern. Some women take HRT for only a few years, until the worst of their menopausal symptoms have passed, while others take it for a decade or more. Many researchers believe that there is little or no increased risk of breast cancer associated with short-term use (10 years or less), while long-term use produces a moderately increased risk. However, some evidence suggests that the risk of breast cancer is increased in current users of HRT but not in those who used HRT in the past.
Still another area of controversy centers on whether women who have had breast cancer can take HRT, especially since treatments for breast cancer can often lead to early menopause in younger women. Use of HRT in breast cancer survivors is widely discouraged, based on concern that exposure to the estrogen in HRT would increase their risk for recurrence. However, some scientists question the validity of this concern, and research is under way to determine whether breast cancer survivors are truly at increased risk if they take HRT.
The Future of HRT
Many women who are eligible decide against using HRT due to studies that have produced conflicting results about the risk of developing cancer. Often, they prefer to take other steps (such as exercise and a well-balanced diet that includes supplementation with calcium) to reduce their risk of osteoporosis and heart disease.
In an effort to find definitive answers, the Women's Health Initiative (WHI) and several other studies are evaluating the effects of long-term use of HRT in postmenopausal women. ponsored by the National Institutes of Health, the WHI is a 15-year nationwide clinical study that will investigate heart disease, osteoporosis, and breast and colon cancers in 63,000 women ages 50 to 79. Long-term, well-designed studies such as the Women's Health Initiative should be able to answer many of the lingering questions about the true effects of HRT.
Weighing benefits and risks is part of all medical decisions. Many physicians and researchers feel that HRT's potential beneficial effects on cardiovascular disease, osteoporosis, and general quality of life outweigh the possible risk of developing cancer. Other doctors are concerned about the possible negative effects of HRT; instead, they recommend exercise, changes in diet, or other medications. Physicians also emphasize, however, that each woman's decision about whether or not to take HRT and, if so, for how long, must be an individual one made in cooperation with her physician. This decision should be based on the woman's individual risk profile--her personal and family medical history, not only of cancer, but also of heart disease, stroke, and osteoporosis.
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