Section 22. Women's Health Issues

Chapter 243. Menopause

Topics: Introduction | Premature Menopause

Introduction

Menopause is the permanent end of cyclic functioning of the ovaries and thus of menstrual periods.

Menopause occurs because as women age, the ovaries produce smaller and smaller amounts of estrogen and progesterone. Estrogen and progesterone are the hormones that control the monthly cycle of egg release (ovulation (see Section 22, Chapter 241)). Thus, as women approach menopause, an egg is released in fewer and fewer cycles, and eventually, egg release stops. As a result, menstrual periods end and pregnancy is no longer possible. A woman's last period can be identified only later, after she has had no periods for at least 6 months. (Women who do not wish to become pregnant should use birth control until 1 year has passed since their last menstrual period.)

A distinctive transitional period called perimenopause occurs before and just after menopause. During perimenopause, estrogen and progesterone levels fluctuate widely. Estrogen levels may be high at the beginning of this transitional period, but for short intervals, no estrogen may be produced. These fluctuations explain why many women in their 40s report bouts of menopausal symptoms, which may subside without treatment.

In the United States, the average age at which menopause occurs is about 51 to 52. However, menopause may occur normally in women as young as 40. Premature menopause is menopause occurring before age 40 (see Section 22, Chapter 243).

Artificial menopause results from a medical treatment that reduces or stops hormone production by the ovaries. Examples are surgery to remove the ovaries, surgery that unintentionally reduces the blood supply to the ovaries, and chemotherapy or radiation therapy to the pelvis, including the ovaries, to treat cancer. Surgery to remove the uterus (hysterectomy) ends menstrual periods but does not cause menopause as long as the ovaries are functioning.

Symptoms

During perimenopause, symptoms may be nonexistent, mild, moderate, or severe. Perimenopausal symptoms are thought to be caused by the fluctuations in hormone levels that occur as women approach menopause.

Irregular menstrual periods, which occur more or less often, may be the first symptom of perimenopause. Periods may be shorter or longer, lighter or heavier. They may not occur for months, then become regular again. However, periods may occur regularly until menopause.

Hot flashes affect three fourths of women. Most women have hot flashes for more than 1 year, and up to one half of women have them for more than 5 years. What causes hot flashes in unknown, but they may be related to fluctuations in hormone levels. Hot flashes seem to result in the widening (dilating) of blood vessels near the skin's surface. As a result, blood flow increases, causing the skin, especially on the head and neck, to become red and warm (flushed). Perspiration may be profuse. Hot flashes are sometimes called hot flushes because of this warming effect. A hot flash lasts from 30 seconds to 5 minutes and may be followed by chills.

Other symptoms that may occur around the time of menopause include mood changes, depression, irritability, anxiety, nervousness, insomnia, loss of concentration, headache, and fatigue. These symptoms may be related to the decreases in estrogen levels occurring at the same time. But the precise relationship between estrogen levels and symptoms is unclear. Night sweats, which are related to hot flashes, may disturb sleep, contributing to fatigue and irritability. However, sleep disorders are common even among women who do not have hot flashes.

Women may feel dizzy occasionally or have tingling (pins-and-needles) sensations. They may feel the heart beating very forcefully or rapidly (have palpitations). Weight gain may occur during perimenopause and continue after menopause. But this weight gain is unrelated to the changes in hormone levels and may just be part of normal aging.

Many of the symptoms of perimenopause, although disturbing, become less frequent and less intense after menopause. In contrast, the complications of menopause, which result from the decrease in estrogen, are progressive, unless measures to prevent them are taken.

After menopause, the decrease in estrogen causes changes in the reproductive tract over a period of months or years. The lining of the vagina becomes thinner, drier, and less elastic (a condition called vaginal atrophy). These changes may make sexual intercourse painful and may increase the risk of inflammation (vaginitis). Other genital organs--the labia minora, clitoris, uterus, and ovaries--decrease in size. Sex drive (libido) commonly decreases. The effect of menopause on the ability to have an orgasm varies from woman to woman. In many women, the ability is unaffected. It improves in some women but is lost in others.

The lining of the urethra becomes thinner, and the muscles that control the outflow of urine (around the bladder outlet) become weaker. As a result, a burning sensation may occur when urinating, and urinary tract infections may develop more easily. Many postmenopausal women have stress incontinence, in which small amounts of urine escape from the bladder during laughing, coughing, or other activities that put pressure on the bladder (see Section 11, Chapter 147). Some women develop urge incontinence, which is an abrupt, intense urge to urinate that cannot be suppressed.

As estrogen decreases, the amount of collagen, a protein that makes skin strong, and elastin, a protein that makes skin elastic, also decrease. Thus, the skin may become thinner, dryer, less elastic, and more vulnerable to injury.

The decrease in estrogen often leads to a decrease in bone density and sometimes to osteoporosis (see Section 5, Chapter 60), because estrogen helps maintain bone. Bone becomes less dense and weaker, making fractures more likely. During the first 2 years after menopause, bone density decreases by about 3 to 5% each year. After that, it decreases by about 1 to 2% each year.

After menopause, levels of lipids, particularly LDL cholesterol, increase in women. The increase in lipid levels may partly explain why coronary artery disease becomes more common among women after menopause. Also, until menopause, the high estrogen levels seems to protect against the disease.

Diagnosis

In about three fourths of women, menopause is obvious. If menopause needs to be confirmed (particularly in younger women), blood tests are performed to measure levels of estrogen and follicle-stimulating hormone (which stimulates the ovaries to produce estrogen and progesterone).

Before any treatment is started, doctors ask women about their medical and family history and perform a physical examination, including breast and pelvic examinations and measurement of blood pressure. Mammography is also performed. Blood tests may be performed, and bone density may be measured. The information thus obtained helps doctors determine the woman's risk of developing disorders after menopause. For women with a history of abnormal bleeding from the vagina, an endometrial biopsy (see Section 22, Chapter 242) may be performed to check for signs of cancer. A small sample of tissue is removed from the lining of the uterus (endometrium) and is examined under a microscope.

Treatment

Not consuming spicy foods, hot beverages, caffeine, and alcohol may help prevent hot flashes, because these substances can trigger hot flashes. Eating foods rich in B vitamins or vitamin E or foods rich in plant estrogens (phytoestrogens), such as tofu, soy milk, tempeh, and miso, may also help. Not smoking, avoiding stress, and exercising regularly may help improve sleep as well as relieve hot flashes. Wearing layers of clothing, which can be taken off when a woman feels hot and put on when she feels cold, can help her cope with hot flashes. Wearing clothing that breathes, such as cotton underwear and sleepwear, may enhance comfort.

Aerobic exercise, relaxation techniques, meditation, massage, and yoga may help relieve depression, irritability, and fatigue, as well as reduce hot flashes. Reducing the number of calories consumed and exercising more can help prevent weight gain. Weight-bearing exercise (such as walking, jogging, and weight lifting) and taking calcium and vitamin D supplements slow the loss of bone density.

Many of these measures--losing weight if needed, stopping smoking, and exercising regularly--plus decreasing the total amount of fat and cholesterol in the diet may be recommended to help lower cholesterol levels and thus reduce the risk of atherosclerosis.

If vaginal dryness makes sexual intercourse painful, an over-the-counter vaginal lubricant may help. Staying sexually active also helps by stimulating blood flow to the vagina and surrounding tissues and by keeping tissues flexible. Kegel exercises may help with bladder control (see Section 22, Chapter 250). For these exercises, a woman tightens the pelvic muscles as if stopping urine flow.

Hormone Therapy: For women who have a uterus, hormone therapy usually includes a progestin, such as medroxyprogesterone, as well as estrogen. A progestin, a drug similar to the hormone progesterone, is given with estrogen to reduce the risk of cancer of the uterine lining (endometrial cancer). A progestin without estrogen may be prescribed for women who have endometrial cancer or breast cancer. Progestins are available in synthetic and natural forms. The natural forms are identical to a woman's own progesterone.

Benefits and risks: Hormone therapy (estrogen plus a progestin) can relieve many symptoms of menopause and may be appropriate if the benefits seem to outweigh the risks. Whether to take hormone therapy is a difficult decision that must be made by a woman and her doctor based on the woman's individual situation. The decision is complicated because interpreting and applying the information about estrogen's benefits and risks is difficult. Recent evidence suggests that hormone therapy is not appropriate for all women. Recent evidence has also raised questions about the long-term use of hormone therapy. For this reason, taking hormone therapy for more than 5 years is no longer recommended.

Estrogen is the most effective treatment for hot flashes. It can prevent the drying and thinning of vaginal and urinary tract tissues, thus improving sexual function and helping prevent infections. Estrogen may help prevent the skin from becoming dry and inelastic.

Estrogen helps prevent or slow the progression of osteoporosis. During the first year estrogen is taken, bone density may increase by 3% and remain at that level as long as estrogen is taken. Women who are taking hormone therapy to relieve symptoms experience this benefit. However, for most women, taking hormone therapy with the sole purpose of preventing osteoporosis is no longer recommended.

The effect of estrogen on the development of atherosclerosis, including the risk of heart attack and stroke, is not as clear-cut. Estrogen decreases the level of low-density lipoprotein (LDL) cholesterol, the bad cholesterol, and increases the level of high-density lipoprotein (HDL) cholesterol, the good cholesterol. However, estrogen does not appear to improve outcome after a heart attack, increases the risk of blood clots, and may increase the risk of heart attack and stroke. Therefore, taking hormone therapy (estrogen plus a progestin) to prevent coronary artery disease or its consequences (such as heart attack or stroke) is no longer recommended regardless of whether or not a woman has had a heart attack, a stroke, or blood clots.

Estrogen used alone increases the risk of endometrial cancer from about 1 to 4 in 1,000 women each year. The risk is higher with higher doses and longer use of estrogen. Taking a progestin with estrogen almost eliminates the risk of endometrial cancer and reduces the risk below that for women who do not take hormone therapy. A woman whose uterus has been removed has no risk of developing this cancer and thus does not need to take a progestin. Usually, estrogen, with or without a progestin, is not prescribed for women who have or have had advanced endometrial cancer or who have vaginal bleeding of unknown cause.

Taking hormone therapy for more than 4 years appears to increase the risk of breast cancer. The longer women take hormone therapy and the higher the dose, the higher the risk of developing breast cancer.

During the first year of estrogen therapy, the risk of developing gallstones is modestly increased.

Estrogen therapy may worsen liver disorders and acute intermittent porphyria. Therefore, this therapy is usually not prescribed for women who have or have had these disorders.

Estrogen, especially at high doses, may have side effects, including nausea, breast tenderness, headache, fluid retention, and mood changes.

A progestin taken alone may relieve hot flashes and may help prevent osteoporosis but does not affect vaginal dryness. Synthetic progestins increase the LDL (the bad) cholesterol level and decrease the HDL (the good) cholesterol level and may increase the risk of atherosclerosis. Side effects of progestins include abdominal bloating, breast discomfort, headache, mood changes, and acne. However, a type of progestin called micronized progesterone appears to have fewer side effects and may not adversely affect cholesterol levels.

Dosage forms: Estrogen and a progestin can be taken in several ways. They may be taken as two tablets or a combination tablet. Commonly, estrogen and a progestin are taken every day. This schedule typically causes irregular vaginal bleeding for the first year or more of therapy. Alternatively, a cyclic monthly schedule may be followed: Estrogen is taken daily, and a progestin is taken for 12 to 14 days each month. With this schedule, most women have monthly vaginal bleeding.

Other forms include progestin injections, an estrogen skin patch (transdermal estrogen), a combination estrogen-progestin patch, and estrogen creams.

An estrogen cream may be applied to the vagina, or a ring may be inserted into the vagina (similar to a diaphragm). Or an estrogen tablet may be inserted into the vagina. Applied in these ways, estrogen may help prevent thinning and drying of the vaginal lining. Such treatment helps prevent intercourse from being painful. Some of the estrogen cream is absorbed into the bloodstream, particularly as the vaginal lining becomes healthier. Theoretically, the cream form of estrogen can increase the risk of endometrial cancer. Therefore, if women use this form, they should also take a progestin. The vaginal tablet and ring forms (which do not enter the bloodstream in substantial amounts) may be suggested for women who have breast cancer or a high risk of developing it.

Selective Estrogen Receptor Modulators (SERMs): These drugs function like estrogen in some parts of the body. The only SERM currently used to prevent problems related to menopause is raloxifene. Like estrogen, raloxifene helps prevent bone density from decreasing in postmenopausal women and increases the chance of developing blood clots (from 1 to 2 or 3 in 10,000 women). Raloxifene also prevents fractures of the bones in the spine (vertebrae). However, raloxifene may have effects opposite to those of estrogen in other parts of the body. For example, hot flashes worsen in about 1 in 10 women. It also does not appear to increase the risk of endometrial cancer, and it inhibits the growth of breast tissue.

Tamoxifen, another SERM, is used to treat breast cancer and prevent its recurrence and to prevent breast cancer in women who have a high risk of developing it. Because raloxifene is similar to tamoxifen, raloxifene is being studied for the prevention of breast cancer.

Other Drugs: Several other types of drugs can help reduce the severity of some of the symptoms associated with menopause. Clonidine, which is used to treat high blood pressure, can reduce the intensity of hot flashes. An antidepressant, such as paroxetine, sertraline, or venlafaxine, may relieve hot flashes. Antidepressants may also help relieve depression, anxiety, and irritability (see Section 7, Chapter 101). Sleep aids may help relieve insomnia (see Section 6, Chapter 81).

Lipid-lowering drugs (see Section 12, Chapter 157) may be taken to lower cholesterol levels, reducing the risk of atherosclerosis. Bisphosphonates, used alone or taken with estrogen, can be taken to reduce the risk of osteoporosis (see Section 5, Chapter 60). They increase bone density and are the only drugs proved to reduce the risk of spine and hip fractures.

Testosterone, the main male sex hormone, taken with estrogen is an option for relief of some symptoms of menopause. Taking testosterone may help increase sex drive, increase bone density, improve mood, and increase energy. Synthetic testosterone is available as a tablet (combined with estrogen). Natural testosterone is available as an injection or a cream. Side effects include decreasing the HDL (the good) cholesterol level. When taken in usual doses, testosterone may have some masculinizing effects.

See the drug table Some Drugs Used to Treat Symptoms and Complications of Menopause.

Alternative Medicine: Some women take medicinal herbs and other supplements to relieve hot flashes, irritability, mood changes, and memory loss. Examples are black cohash, DHEA (dehydroepiandrosterone), dong quai, evening primrose, ginseng, and St. John's wort. However, such remedies are not regulated. That is, they have not been shown to be safe or effective for this use, and what their ingredients are and how much of each ingredient a product contains are not standardized (see Section 2, Chapter 19). Furthermore, some supplements can interact with other drugs and can worsen some disorders. Women who are considering taking such supplements are advised to discuss them with a doctor.