When menopause occurs naturally, it tends to take place anywhere between the ages of forty-eight and fifty-two, but it can occur as early as your late thirties, or as late as your mid-fifties. When menopause occurs before thirty-five, it is technically considered premature menopause, but just as menarche is genetically predetermined, so is menopause. For an average woman with an unremarkable medical history, what she eats or does in terms of activity will not influence the timing of her menopause. Women who have had chemotherapy, though, or have been exposed to high levels of radiation (such as radiation therapy in their pelvic area for cancer treatment) may go into menopause earlier. In any event, the average age of menopause is fifty.

Other possible causes of early menopause include mumps (in small groups of women, the infection causing the mumps has been known to spread to the ovaries, prematurely shutting them down) and specific autoimmune diseases, such as lupus or rheumatoid arthritis (in some of these women, their bodies develop antibodies and attack the ovaries). Smokers also tend to have earlier menopause.

The Stages of Natural Menopause

Socially, the word menopause refers to a process, not a precise moment in the life of your menstrual cycle. Medically, the word menopause does indeed refer to one precise moment: the date of your last period. The events preceding and following menopause amount to a huge change for women both physically and socially. Physically, this process has four stages:

1. Premenopause. Although some doctors may refer to a thirty-two-year-old woman in her childbearing years as premenopausal, this is not really an appropriate label. The term premenopause ideally refers to women on the cusp of menopause. Their periods have just started to get irregular, but they do not yet experience any classic menopausal symptoms such as hot flashes or vaginal dryness. A woman in premenopause is usually in her mid-to-late forties. If your doctor tells you that you're premenopausal, you might want to ask him or her how he or she is using this term.
2. Perimenopause. This term refers to women who are in the thick of menopause. Their cycles may be wildly erratic, and they are experiencing hot flashes and vaginal dryness. This label is applicable for about four years, covering the first two years prior to the official "last" period to the next two years following the last menstrual period. Women who are perimenopausal will be in the age groups discussed above, averaging about age fifty-one.
3. Menopause. This refers to your final menstrual period. You will not be able to pinpoint your final period until you've been completely free from periods for one year. Then, you count back to the last period you charted, and that date is the date of your menopause. Note: After more than one year of no menstrual periods, any vaginal bleeding is now considered abnormal.
4. Postmenopause. This term refers to the last third of most women's lives, ranging from women who have been free of menstrual periods for at least one year to women celebrating their one hundredth birthday. In other words, once you're past menopause, you'll be referred to as postmenopausal for the rest of your life. The terms postmenopausal and perimenopausal are sometimes used interchangeably, but this is technically inaccurate.

Used in a social context, nobody really bothers to break down menopause as precisely. When you see the word menopausal in a magazine article, you are seeing what's become acceptable medical slang, referring to women who are premenopausal and perimenopausal, a time frame that includes the actual menopause. When you see postmenopausal in a magazine article, you are seeing another accepted medical slang, which includes women who are in perimenopause and "official" postmenopause.

"Diagnosing" Premenopause or Perimenopausal

When you begin to notice the signs of menopause, either you'll suspect the approach of menopause on your own, or your doctor will put two and two together when you report your symptoms. Two very simple tests will accurately determine what's going on and what stage of menopause you're in. Your follicle stimulating hormone (FSH) levels will dramatically rise as your ovaries begin to shut down; these levels are easily checked through one blood test. In addition, your vaginal walls will thin, and the cells lining the vagina will not contain as much estrogen. Your doctor will simply take a Pap-like smear from your vaginal walls -- simple and painless -- and analyze the smear to check for vaginal "atrophy," the thinning and drying out of your vagina. As I'll discuss below, you'll need to keep track of your periods and chart them as they become irregular. Your menstrual pattern will be an added clue to your doctor about whether you are pre- or perimenopausal.

Recognizing the Signs of Natural Menopause

In the past, a long list of hysterical symptoms have been attributed to the "change of life," but medically, there are really just three classic short-term symptoms of menopause: erratic periods, hot flashes, and vaginal dryness. All three are caused by a decrease in estrogen. As for the emotional symptoms of menopause, such as irritability, mood swings, melancholy, and so on, they may or may not be directly related to hormone changes. Some women may find that estrogen therapy improves these symptoms, some may not, and some actually have psychiatric illnesses that require appropriate treatment. Decreased levels of estrogen, however, can make you more vulnerable to stress, depression, and anxiety, because estrogen loss affects REM sleep.

Every woman entering menopause will experience a change in her menstrual cycle. Not all women will experience hot flashes or even notice vaginal changes. This is particularly true if a woman is overweight. Estrogen is stored in fat cells, which is why overweight women also tend to be more at risk for estrogen-dependent cancers. The fat cells convert fat into estrogen, creating a type of estrogen reserve that the body will use during menopause, which can reduce the severity of estrogen loss symptoms. In addition, many women go through menopause without experiencing changes in their moods. The assumption that mood swings always accompany menopause, or that women who suffer from premenstrual syndrome (PMS) will always experience more severe menopausal symptoms, is an absolute myth. It is believed, however, that women who do suffer from PMS are more likely to experience mood swings.

Erratic Periods

Every woman will begin to experience an irregular cycle before her last period. Cycles may become longer or shorter with long bouts of amenorrhea. Sometimes she will just stop having her periods, never experiencing an erratic phase in her cycles. Periods may suddenly become light and scanty or heavy and crampy. The impact of suddenly irregular, "wild" cycles can be disturbing because menstrual cycle changes may also signify other problems. It's imperative to chart your periods and try to sort out your own pattern of "normal" irregular cycles. Bring your chart to your gynecologist to help confirm your suspicions that you are indeed entering menopause. If you're not entering menopause, you'll need to isolate the cause of your cycle changes.

Of course, since you can go into menopause earlier than you might have anticipated, irregular cycles may not always be on your list of suspected causes behind your sudden cycle changes. Is there any way you can more accurately predict when your own menopause might occur? Yes. Although most women can expect their menopause to occur in their fifties, women who go into earlier menopause will usually have a family history of earlier menopause. Periods will generally become erratic approximately two years before the final period. However, some women may experience a longer premenopausal process than others.

Hot Flashes

Roughly 85 percent of all pre- and perimenopausal women experience "hot flashes." Hot flashes can begin when periods are either still regular or have just started to become irregular. They usually stop one to two years after your final menstrual period. A hot flash can feel different for each woman. Some women experience a feeling of warmth in their faces and upper bodies; some women experience sweating and chills. Some women feel anxious, tense, dizzy, or nauseous just before the hot flash; some feel tingling in their fingers or heart palpitations just before. Some women will experience their hot flashes during the day; others will experience them at night and may wake up so wet from perspiration that they need to change their bedsheets or nightclothes.

Nobody really understands what causes a hot flash, but researchers believe it has to do with mixed signals from the hypothalamus, which controls both body temperature and sex hormones. Normally, when the body is too warm, the hypothalamus sends a chemical message to the heart to cool off the body by pumping more blood, causing the blood vessels under the skin to dilate, which makes you perspire. During menopause, however, it's believed that the hypothalamus gets confused and sends this "cooling off" signal at the wrong times. A hot flash is not the same as being overheated. Although the skin temperature often rises between 4 to 8*F, the internal body temperature drops, creating this odd sensation.

Why does the hypothalamus get so confused? The answer is decreasing levels of estrogen. We know this because when synthetic estrogen is given to replace natural estrogen in the body, hot flashes disappear. Some researchers believe that a decrease in luteinizing hormone (LH) is also a key factor, and a variety of other hormones that influence body temperature are being looked at as well. Although hot flashes are harmless in terms of health risks, they are disquieting and stressful. Women in the following categories will experience more severe hot flashes than will others:

• Women who are in surgical menopause.
• Women who are thin. When there's less fat on the body to store estrogen reserves, estrogen loss symptoms are more severe.
• Women who don't sweat easily. An ability to sweat makes extreme temperatures easier to tolerate. Women who have trouble sweating may experience more severe flashes.

Just as you must chart your periods when your cycles become irregular, it's also important to chart your hot flashes. Keep track of when the flashes occur, how long they last, and number their intensity from 1 to 10. This will help you determine a pattern for the flashes and allow you to prepare for them in advance, which will help reduce the stress. Report your hot flashes to your doctor, just as you would any changes in your cycle. Symptoms of hot flashes can also indicate other health problems, such as circulatory problems.

Short of taking ERT or HRT (see below), the only thing you can do about your hot flashes is to lessen your discomfort by adjusting your lifestyle to cope with the flashes. The more comfortable you are, the less intense your flashes will feel. Once you establish a pattern by charting the flashes, you can do a few things around the time of day your flashes occur. Some suggestions:

• Avoid synthetic clothing, such as polyester, because it traps perspiration.
• If you have night sweats, use only 100 percent cotton bedding.
• Avoid clothing with high necks and long sleeves.
• Dress in layers.
• Keep cold drinks handy.
• If you smoke, cut down or quit. Smoking constricts blood vessels and can intensify and prolong a flash.
• Avoid "trigger" foods such as caffeine, alcohol, spicy food, and sugar, and avoid eating large meals. Substitute herbal teas for coffee or regular tea.
• Discuss with your doctor the benefits of taking vitamin E supplements. Evidence suggests vitamin E is essential for proper circulation and production of sex hormones.
• Exercise to improve your circulation.
• Reduce your exposure to the sun; sunburn will aggravate your hot flashes because burnt skin cannot regulate heat as effectively. (Sun effects are discussed below.)

Vaginal Changes

Estrogen loss will also cause vaginal changes. Since the production of estrogen causes the vagina to stay moist and elastic, the loss of estrogen will cause the vagina to become drier, thinner, and less elastic. This may also cause the vagina to shrink slightly in terms of width and length. In addition, the reduction in vaginal secretions causes the vagina to be less acidic. This can put you at risk for more vaginal infections, particularly yeast overgrowth. Again, women who are in surgical menopause and women who are physically thinner tend to have more severe vaginal dryness and repeated yeast infections.

As a result of these vaginal changes, you'll notice a change in your sexual activity. Your vagina may take longer to become lubricated, or you may have to depend on lubricants to have comfortable intercourse.

Estrogen loss can affect other parts of your sex life as well. Your sexual libido may actually increase because testosterone levels can rise when estrogen levels drop. (The general rule is that your levels of testosterone will either stay the same or increase.) However, women who do experience an increase in sexual desire will also be frustrated that their vaginas are not accommodating their needs. First, there is the lubrication problem: More stimulation is required to lubricate the vagina naturally. Second, a decrease in estrogen means that less blood flows to the vagina and clitoris, which means that orgasm may be more difficult to achieve or may not last as long as it normally has in the past.

Other changes involve the breasts. Normally, estrogen causes blood to flow into the breasts during arousal, which makes the nipples more erect, sensitive, and responsive. Estrogen loss causes less blood to flow to the breasts, which makes them less sensitive. Finally, since the vagina shrinks as estrogen decreases, it doesn't expand as much during intercourse, which may make intercourse less comfortable, particularly since the vagina is less lubricated.

Source: M. Sara Rosenthal. From The Gynecological Sourcebook, Third Edition, by arrangement with The NTC/Contemporary Publishing Group, Inc.