The Basics of Menopause

The change of life. The end of fertility. The beginning of freedom. Whatever people call it, menopause is a unique and personal experience for every woman. It's a natural event that marks the end of fertility and childbearing years. Technically, menopause results when the ovaries run out of eggs and decrease production of the sex hormones estrogen, progesterone and, to a lesser extent, androgen.

Why or how does this happen? A woman is born with about 500,000 egg cells, but only about 400 to 500 ever mature fully to be released during the menstrual cycle. The rest degenerate over the years. During the reproductive years, a gland in the brain generates hormones that cause a new egg to be released from its follicle each month. As the follicle develops, it produces the sex hormones estrogen and progesterone, which thicken the lining of the uterus. This enriched lining is prepared to receive and nourish a fertilized egg, which could develop into a fetus. If fertilization does not occur, estrogen and progesterone levels drop, the lining of the uterus breaks down, and menstruation occurs.


For reasons unknown, your ovaries gradually begin to change in hormone production during your mid-30s. In your late 40s, the process accelerates and hormones fluctuate more, causing irregular menstrual cycles and unpredictable episodes of menstrual bleeding. By your early to mid-50s, periods finally end altogether. However, estrogen production does not completely stop. The ovaries decrease their output significantly, but still may produce a small amount of estrogen.

The other female hormone

Progesterone, the other female hormone, works during the second half of the menstrual cycle to prepare the uterine lining as a viable home for an egg, and to shed the lining if the egg is not fertilized. If you skip a period, your body may not be making enough progesterone to break down the uterine lining. However, your estrogen levels may remain high even though you are not menstruating. At menopause, hormone levels don't always decline uniformly. Production of estrogen and progesterone is erratic and unpredictable at this time.

Most women can tell if they are approaching menopause because their menstrual periods start changing. The "menopause transition" is a term used to describe this time. Perimenopause is another term used by some to describe as "being in menopause." But menopause itself — as defined by health care professionals — is only one day in a woman's life — the day after she has not had a menstrual period for 12 consecutive months, and no other biological or physiological cause can be identified. Until 12 consecutive months have passed without a menstrual period, a woman in her late 40s may still be able to get pregnant, despite irregular periods.

Although the majority of women experience "natural" or spontaneous menopause, some women may experience menopause due to one of a number of medical interventions. Surgically removing both ovaries, a procedure known as bilateral oophorectomy, will trigger menopause, at any age. Induced menopause can also occur if the ovaries are damaged by radiation, chemotherapy or by certain drugs. Certain medical conditions also may cause menopause to occur earlier.

Copyright 2003 National Women's Health Resource Center Inc. (NWHRC)

The Basics of Menopause (<i>cont'd</i>)

Everybody's menopause is unique

Just as every woman's body is unique, your menopause experience will be a highly personal one. For example, 15 to 20 percent of women experience no physical symptoms at all, except the end of their menstrual periods.


Some women go through menopause before age 51 and some experience it a bit later. Early menopause is defined as occurring at any age younger than age 40 or 45. Early menopause can occur naturally, but premature menopausal symptoms may signal an underlying condition, so it is important to discuss any symptoms with your health care professional. Menopause can occur as early as your 30s and, rarely, as late as in your 60s. However, there is no correlation between the time of a woman's first period and her age at menopause. In addition, age at menopause is not influenced by race, height, the number of children a woman has had or whether she took oral contraceptives for birth control.

What does influence the time of menopause? Genetics are a key factor. And, women who smoke cigarettes experience menopause two years earlier, on average, than nonsmoking women.

About six years prior to natural menopause, typically in a woman's late 40s, menopause-related changes begin. Physical changes triggered by hormonal fluctuations during this time frame include irregular menstrual patterns.

One of the most common and annoying symptoms you may notice during your 40s is that your periods become irregular. They may be heavy one month and then very light the next. They may get shorter or last longer. You may even begin to skip your period every few months or lose track of when your periods should start and end. These symptoms are caused by irregular estrogen and progesterone levels. Levels of hormones vary erratically and may be higher or lower than normal during any cycle. For example, if you don't ovulate one month — which is common for women in their late 40s — progesterone isn't produced to stimulate menstruation and estrogen levels continue to rise. This can cause spotting throughout your cycle or heavy bleeding when menstruation does start.

One note of caution: although irregular menstrual periods are common as you get closer to menopause, they can also be a symptom of uterine abnormalities or uterine cancer. If your periods stop for several months and then start again with heavy bleeding or if you start bleeding after menopause, consult with an obstetrician/gynecologist as soon as possible for an evaluation. Irregular bleeding can also be a symptom of cervical cancer which should be picked up by a Pap test (see screening recommendations below). Be sure to mention any menstrual irregularities during regular check-ups. A uterine biopsy or vaginal ultrasound are the only ways to evaluate if irregular symptoms are abnormal.

Copyright 2003 National Women's Health Resource Center Inc. (NWHRC)

The Basics of Menopause (<i>cont'd</i>)

Other changes and signs of menopause include:

  • hot flashes (sudden warm feeling, sometimes with blushing)
  • night sweats (hot flashes that occur at night, often disrupting sleep)
  • fatigue (probably from disrupted sleep patterns)
  • mood swings
  • early morning awakening
  • vaginal dryness
  • fluctuations in sexual desire or response
  • difficulty sleeping

Although there is a wide range of possible menopause-related conditions, most women going through natural menopause have only mild disturbances during the perimenopausal years. However, you should be aware that there are at least two major health conditions that can develop in the years ahead because of the decrease in hormone production that occurs at menopause: coronary artery disease and osteoporosis.


Up until menopause, estrogen helps protect against plaque buildup in your arteries. It does this by helping to raise HDL cholesterol (good cholesterol), which helps remove LDL-cholesterol (the type that contributes to the accumulation of fat deposits called plaque along artery walls). After menopause, your risk for developing coronary artery disease (CAD) — a condition in which the veins and arteries that take blood to the heart become narrowed or blocked by plaque — increases steadily. Heart attack and stroke are caused by atherosclerotic disease, in most cases.

Also, the body's own estrogen helps prevent bone loss and works together with calcium and other hormones and minerals to help build bones. Your body constantly builds and remodels bone through a process called resorption and deposition. Up until around age 30, the body makes more new bone than it breaks down. But, once estrogen levels start to decline, this process also slows down. By menopause, your body breaks down more bone than it rebuilds. In the years immediately after menopause, some women risk losing as much as 20 percent of their bone mass. Although bone loss eventually levels out in your late 50s, in the years ahead, keeping bone structures strong and healthy to prevent osteoporosis becomes more of a challenge. Osteoporosis occurs when bones become too weak and brittle to support normal activities.

Not all women develop heart disease or osteoporosis. Many more things affect your heart and your bones than estrogen alone. For example, exercise improves your cardiovascular system — your heart, lungs and blood vessels — at any age. It can help decrease high blood pressure, a concern for one out of every three women over age 60. It can also help reduce weight gain, a major risk factor for heart disease, diabetes and many other health conditions common to older women. You are never too old to begin or continue exercising. A simple walking routine for 30 minutes three to five days a week can provide health benefits. There are other exercise options. Talk to your health care professional about which ones fit your lifestyle and medical needs.

If your bones are strong and healthy as you enter menopause, you'll have better bone structure to sustain you as you age. Bone loss varies from woman to woman. You can also improve bone strength as you age by exercising regularly and making sure you get enough calcium in your diet or from supplements. Exercise also helps improve balance, muscle tone and flexibility, which can diminish with aging. Weakness in these areas can lead to more frequent falls, broken bones and longer healing periods.

Women today can expect to live as much as one-third of their lives beyond menopause. In the next decade, more women than ever before — as many as 52 million — will be age 50 or older. The years following menopause can be healthy years, depending on how you take care of yourself.

Copyright 2003 National Women's Health Resource Center Inc. (NWHRC)