The average age for women to have their last period is about 50. But it's normal for menopause to occur any time from age 41 to 59. A woman often goes through menopause at about the same age as her mother.

Women who have both ovaries removed will go through "surgical menopause" at the time of their surgery. If the uterus is taken out but the ovaries are left, a woman won't have periods but she will only go through menopause when her ovaries stop making estrogen.If you stop having periods early--before age 40--your doctor can do a blood test to see if you're going through menopause.

Menopause is a gradual process that can take several years. You're not really through menopause until you haven't had a period for 12 months.Menopausal hormone therapy is a treatment that can relieve the symptoms many women have during menopause. Regular doses of hormones are taken to replace some of the natural hormones that decrease at menopause. The 2 main female hormones are estrogen and progesterone.

Hormone Replacement Therapy (HRT) is medication containing one or more female hormones, commonly estrogen plus progestin (synthetic progesterone). Some women receive estrogen-only therapy (usually women who have had their uterus removed).

Until July 2002, hormone replacement therapy had been the standard therapy in the United States for treating menopausal symptoms. Not only did hormone replacement therapy relieve such discomforts as hot flashes and vaginal dryness, it also seemed to protect against several postmenopausal conditions, such as osteoporosis and heart disease.

The loss of natural estrogen as women age may contribute to the higher risk of heart disease after menopause. However, in light of recent results from clinical trials, the American Heart Association does not advise women to take postmenopausal hormone therapy (PHT, formerly called hormone replacement therapy or HRT) to reduce the risk of coronary heart disease or stroke.

But in July 2002, the Women's Health Initiative — a large, multitiered clinical trial sponsored by the National Institutes of Health — reported that hormone replacement therapy actually posed more health risks than benefits for women in the clinical trial. And as the number of health hazards attributed to hormone replacement therapy grew, doctors discontinued routine prescriptions for this popular treatment. The main reason for stopping the estrogen-progestin study was because of a 26% increase in breast cancer.

The Heart Estrogen/progestin Replacement Study (HERS) published earlier in 2002 also showed no benefit for the heart of taking estrogen and progestin. These women were followed for almost 7 years.HRT should not be given strictly for the prevention of high cholesterol or heart disease. Generally, lifestyle changes and medications to lower cholesterol and control blood pressure are recommended for those conditions.

Estrogen taken with progesterone (Prempro) increases the risk of breast cancer.Estrogen taken without progesterone increases the risk of cancer of the uterus. you are at greatest risk of having this type of cancer if you have a condition that causes your body to produce a lot of the hormone estrogen and you have gone through menopause. Having a high level of estrogen in your body does not create a high risk of cancer by itself. It is a risk only when your body also does not have enough of another hormone called progesterone. After you go through menopause, the progesterone in your body decreases or disappears. Usually estrogen levels also drop quite a bit.

Women with breast cancer or a history of blood clots should not take hormone replacement therapy. Also avoid hormone replacement therapy for preventing memory loss, heart disease, heart attacks or strokes.Estrogen plus progestin increased the risk of stroke in older and younger postmenopausal women, in those with and without high blood pressure and in those with no prior history of cardiovascular disease (CVD). Our finding is that this is absolutely not a strategy for primary prevention of cardiovascular disease.

Not only do these findings demonstrate that the combination therapy tested is not effective for primary prevention of stroke and ischemic heart disease, it also allows for women and their physicians to make a more informed decision about risk and benefit when hormone replacement therapy is considered for other conditions.It has become increasingly clear that oral progestin and equine estrogen pills can increase a number of risks, including the risks of exacerbation of existing liver or gallbladder problems and of dangerous blood clots.

Experimental data strongly suggest that estrogens have a role in the development and growth of breast cancer.The sharp decline in the rate of new breast cancer cases in 2003 may be related to a national decline in the use of hormone replacement therapy (HRT), according to a new report in the April 19, 2007, issue of the New England Journal of Medicine. The report used data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute (NCI), part of the National Institutes of Health.

Age-adjusted breast cancer incidence rates in women in the United States fell 6.7 percent in 2003. During this same period, prescriptions for HRT declined rapidly, following highly-publicized reports from the Women’s Health Initiative (WHI) study that showed an increased risk of breast cancer, heart disease, stroke, blood clots, and urinary incontinence among postmenopausal women who were using hormone replacement therapy that included both estrogen and progestin. The two most commonly prescribed forms of HRT in the United States, Premarin® and Prempro™, had their steepest declines starting in 2002-2003 — from 61 million prescriptions written in 2001 to 21 million in 2004.

Led by senior investigator, Donald Berry, Ph.D., of the University of Texas M.D. Anderson Cancer Center, Houston, Texas, the research team showed that the decrease in breast cancer incidence began in mid-2002 and leveled off after 2003. Comparing rates from 2001 and 2004 showed a decrease in annual age-adjusted incidence of 8.6 percent. The decrease occurred only in women over the age of 50 and was more evident in women with cancers that were estrogen receptor (ER) positive — tumors that need estrogen in order to grow and multiply. The speed at which breast cancer rates declined after the WHI announcements may indicate that extremely small ER-positive breast cancers may have stopped progressing, or even regressed, after HRT was stopped.

“Breast cancer is the most frequently diagnosed cancer among women in the United States, and we have made great strides in its treatment,” said NCI Director John E. Niederhuber, M.D. “Still, we don’t know all the causes of breast cancer, and breast cancer rates had been increasing for two decades up to 2002. Finding the simple ways, such as limiting HRT use to decrease breast cancer risk, is a step forward.”

Preliminary findings of this report were presented at the 29th annual San Antonio Breast Cancer Symposium in 2006. Data from 2004, which was of great interest to those present for the meeting, were not available at that time. This report now includes the data from 2004, which show a leveling-off of breast cancer incidence from 2003 to 2004. This observation, combined with a stabilization of HRT use in 2004, further strengthens the association between breast cancer incidence and use of HRT.

Understanding the effect of cessation of HRT may be complex. Effects may vary depending on the type of HRT used and other factors specific to how the hormones affect the body. From the data in this report, it seems that the decline in breast cancer incidence that is related to a nationwide decline in use of HRT may have has run its course, and breast cancer incidence rates may stabilize or even begin to rise again. Researchers do not yet know if this reduction in HRT use will have a long-term effect on rates, or whether reduction in hormone levels simply slowed the growth of clinically detectable tumors, in which case as HRT use stabilizes, breast cancer incidence will begin to rise again.

Several other possibilities were considered to explain the sudden decrease in new breast cancer cases, including changes in reproductive factors, rates of mammography screening, environmental exposures, and changes in diet. HRT was the only risk factor that changed substantially from 2002 to 2003 and provides a possible explanation for this trend. “Recent reports have suggested a small decline in mammography use after 2000,” said Kathy Cronin, Ph.D., of the Surveillance Research Program at NCI. “Screening may play a role as well, and the contribution of mammography to the observed decline in incidence is currently being investigated.”

Because this analysis is based on population statistics, the study does not prove a link between HRT and breast cancer incidence. Only a randomized clinical trial could prove causation. When the link between breast cancer and HRT was first confirmed in the WHI, which was a randomized clinical trial, women in the study were asked to discontinue their study medications (either placebo or hormones), and were encouraged to continue undergoing annual mammography. These women are still being followed, and the WHI researchers are expected to release a follow-up report later this year about the group who received HRT (estrogen and progestin) later this year. This report will provide a much higher level of evidence about the influence of HRT (and cessation of HRT) on the incidence of breast cancer.

“The decision about use of HRT is complex,” says study researcher Christine Berg, M.D., from the National Cancer Institute. “While HRT provides relief from the symptoms of menopause, it may also increase one’s risk of breast cancer. It is important that women meet with their doctor to discuss what decision is right for them, particularly if they are at high risk for breast cancer.”