Menopause is the end of menstrual cycles in women and signals the complete depletion of eggs. Although this event is often described as a single point in time it is actually part of a much longer transition that is often termed the perimenopause. The average age of menopause in the United States is 51 years of age but the perimenopausal transition that precedes it lasts approximately four years.
Although the technical definition involves the loss of eggs and follicles (the small cysts that normally contain the eggs during reproductive life) in the ovary, the significant changes in circulating hormones in the woman have an impact on many other organ systems in the body.
When the woman has normal menstrual cycles, between about age 12 until menopause, the hormones estrogen and progesterone fluctuate in an orchestrated cycle each month. The depletion of eggs at the time of menopause means that these hormones are significantly diminished. The ovary does continue to make hormones such as testosterone. The adrenal gland also continues to make hormones such as androstenedione. These hormones are androgens (commonly perceived to be “male” hormones) and they can be changed into weak estrogens in fat and muscle cells. The amount of each of these hormones that circulate in a particular woman may vary a great deal which can impact the type of symptoms that she has as she transitions through the menopause. Treatment of the menopausal woman therefore needs to be highly individualized.
Some women undergoing the menopausal transition, or after they have fully stopped menstruating, will experience symptoms such as poor sleep, hot flashes, or changes in their sexual desire. These problems are often approached with simple hormone replacement therapy with a woman’s own gynecologist. In some cases, the solutions to these symptoms may be more complex. Individual medical history, the other medical conditions a woman may have, and her hormone profile may impact on treatment options which are suggested to her.
Among the most common of the menopausal symptoms is the hot flash. A woman may notice the sudden onset of flushing of the face and head with accompanying redness and sweating in these areas. While nobody knows the reasons that hot flashes occur, it is associated with a decrease in the amount of circulating estrogen hormone. Reinforcing this fact is the significant reduction in hot flashes occurring once estrogen is replaced in the post-menopausal woman. These episodes often occur at night, waking the woman and interrupting restful sleep. Hot flashes occur variably among individuals but up to three-fourths of women past the menopausal transition experience them. If untreated, this symptom resolves anywhere from a few months to five years after the onset of low estrogen levels. They can also still occur while the woman is having somewhat regular menstrual bleeding.
Vaginal dryness and urogenital atrophy (thinning of the tissue) can also occur. Low estrogen levels allow the vagina to become thin, red and vulnerable to trauma such as what might occur during intercourse. Libido or a woman’s interest in sexual intercourse may be compromised due to the discomfort that occurs. Since the urethra and part of the bladder are estrogen sensitive, a woman may also experience burning on urination and sometimes frequency loss of bladder control. Replacement estrogen may resolve these symptoms to some extent.
Somewhat more difficult to assess, a woman may also suffer some decrease in cognitive ability (thinking and reasoning). This may be from the interference with a normal sleeping pattern that occurs from the hot flashes or from another unknown cause. Some women also experience an increase in irritability, possibly as a result of the effects of low estrogen levels and sleep disruption.
Bone is known to be dependent on estrogen for its normal growth. It has long been recognized that post-menopausal women suffer from debilitating osteoporosis: a loss of bone strength, which may predispose the individual to a non-traumatic fracture. Fractures can occur in the spine, hip and forearm. Classic studies in the 1970s clearly show that replacing estrogen stopped bone loss, stabilized bone strength and in some cases added bone.
The most common cause of death for post-menopausal women in the United States is cardiovascular disease. After menopause, levels of HDL (the “good” cholesterol) decrease, possibly increasing a woman’s risk of heart disease. In addition, the coronary vessels, which provide nutrition and oxygen to the heart itself, have estrogen receptors. Binding of estrogen to these receptors has been shown to relax the vessels so that flow of blood to the heart is improved. It is possible that the loss of estrogen after menopause enhances constriction of these vessels, reducing flow to the heart.
For many years, studies showed that there was a reduction in myocardial infarctions (heart attacks) in women who were undergoing estrogen replacement therapy. However, more recent studies, including the Women’s Health Initiative, suggest that women on estrogen therapy may actually have more heart attacks. Currently, women should not take estrogens to prevent heart disease since there are other medications that are far more effective for this purpose. However, the population that was studied in the WHI was on average older than women who are typically treated for the first time after menopause. In general, women should understand that while there may be a slight increase in the risk of heart disease while being treated with estrogen, the benefit of significant relief from severe menopausal symptoms may be worth the minimal risk.
Decrease in circulating estrogens after menopause results in a reduction in breast volume. There is also an age-related increase in breast cancer risk. Some studies have shown that estrogen replacement may increase this risk, although many researchers dispute this. The risks of replacement should always be weighed against the potential benefit derived from taking estrogens.
Continue reading about possible treatments for menopause symptoms in our Services section.