What is menopause?

Menopause is defined as the state of an absence of menstrual periods for 12 months. The menopausal transition starts with varying menstrual cycle length and ends with the final menstrual period. Perimenopause means "the time around menopause" and is often used to refer to the menopausal transitional period. It is not officially a medical term, but is sometimes used to explain certain aspects of the menopause transition in lay terms. Postmenopause is the entire period of time that comes after the last menstrual period.
Menopause is the time in a woman's life when the function of the ovaries ceases. The ovary (female gonad), is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs (ova) and female hormones such as estrogen. During each monthly menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a Fallopian tube to the uterus.
The ovaries are the main source of female hormones, which control the development of female body characteristics such as the breasts, body shape, and body hair. The hormones also regulate the menstrual cycle and pregnancy. Estrogens also protect the bone. Therefore, a woman can develop osteoporosis (thinning of bone) later in life when her ovaries do not produce adequate estrogen.
Perimenopause is different for each woman. Scientists are still trying to identify all the factors that initiate and influence this transition period.

Sign And Symptoms
Technically, you don't actually "hit" menopause until it's been one year since your final menstrual period. In the United States, that happens about age 51, on average.
The signs and symptoms of menopause, however, often appear long before the one-year anniversary of your final period. They include:

Irregular periods
Decreased fertility
Vaginal dryness
Hot flashes
Sleep disturbances
Mood swings
Increased abdominal fat
Thinning hair
Loss of breast fullness

What Causes Menopause
Causes of menopause include:

Natural decline of reproductive hormones. As you approach your late 30s, your ovaries start making less estrogen and progesterone, the hormones that regulate menstruation. During this time, fewer potential eggs are ripening in your ovaries each month, and ovulation is less predictable. Also, the post-ovulation surge in progesterone — the hormone that prepares your body for pregnancy — becomes less dramatic. Your fertility declines, partially due to these hormonal effects.
These changes become more pronounced in your 40s. Your menstrual periods may become longer or shorter, heavier or lighter, and more or less frequent, until eventually, your ovaries stop producing eggs, and you have no more periods. It's possible, but very unusual, to menstruate every month right up to your last period. More likely, you'll experience some irregularity in your periods.
Hysterectomy. A hysterectomy that removes your uterus, but not your ovaries, usually doesn't cause menopause. Although you no longer have periods, your ovaries still release eggs and produce estrogen and progesterone. But an operation that removes both your uterus and your ovaries (total hysterectomy and bilateral oophorectomy) does cause menopause, without any transitional phase. Your periods stop immediately, and you're likely to have hot flashes and other menopausal signs and symptoms.
Chemotherapy and radiation therapy. These cancer therapies can induce menopause, causing symptoms such as hot flashes during the course of treatment or within three to six months.
Primary ovarian insufficiency. Approximately 1 percent of women experience menopause before age 40. Menopause may result from primary ovarian insufficiency — when your ovaries fail to produce normal levels of reproductive hormones — stemming from genetic factors or autoimmune disease, but often no cause for primary ovarian insufficiency can be found.

Stages of menopause
Because the menopausal transition occurs over months and years, menopause is commonly divided into these stages:

Perimenopause. This is the time you begin experiencing menopausal signs and symptoms, even though you still menstruate. Your hormone levels rise and fall unevenly, and you may have hot flashes and other symptoms. Perimenopause may last four to five years or longer. During this time, it's still possible to get pregnant, but it's quite unlikely.
Postmenopause. Once 12 months have passed since your last period, you've reached menopause. Your ovaries produce much less estrogen and no progesterone, and they don't release eggs. The years that follow are called postmenopause.

What are the complications and effects of menopause on chronic medical conditions?

Osteoporosis
Osteoporosis is the deterioration of the quantity and quality of bone that causes an increased risk of fracture. The density of the bone (bone mineral density) normally begins to decrease in women during the fourth decade of life. However, that normal decline in bone density is accelerated during the menopausal transition. As a consequence, both age and the hormonal changes due to the menopause transition act together to cause osteoporosis.
The process leading to osteoporosis can operate silently for decades. Women may not be aware of their osteoporosis until suffering a painful fracture. The symptoms are then related to the location and severity of the fractures.

Treatment of osteoporosis
The goal of osteoporosis treatment is the prevention of bone fractures by slowing bone loss and increasing bone density and strength. Although early detection and timely treatment of osteoporosis can substantially decrease the risk of future fracture, none of the available treatments for osteoporosis are complete cures for the condition. Therefore, the prevention of osteoporosis is as important as treatment.
Osteoporosis treatment and prevention measures are:

Lifestyle changes including cessation of cigarette smoking, curtailing alcohol intake, exercising regularly, and consuming a balanced diet with adequate calcium and vitamin D.
Calcium and vitamin D supplements may be recommended for women who do not consume sufficient quantities of these nutrients.
Medications that stop bone loss and increase bone strength include alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), zoledronic acid (Reclast), raloxifene (Evista), and calcitonin (Calcimar). Teriparatide (Forteo) is a medication that increases bone formation.

Cardiovascular disease
Prior to menopause, women have a decreased risk of heart disease and stroke when compared with men. Around the time of menopause, however, a women's risk of cardiovascular disease increases. Heart disease is the leading cause of death in both men and women in the U.S.
Coronary heart disease rates in postmenopausal women are two to three times higher than in women of the same age who have not reached menopause. This increased risk for cardiovascular disease may be related to declining estrogen levels, but in light of other factors (see Treatment section below), postmenopausal women are not advised to take hormone therapy simply as a preventive measure to decrease their risk of heart attack or stroke.

Treatments and Pharmacology

Menopause itself requires no medical treatment. Instead, treatments focus on relieving your signs and symptoms and on preventing or lessening chronic conditions that may occur with aging. Treatments include:

Hormone therapy. Estrogen therapy remains, by far, the most effective treatment option for relieving menopausal hot flashes. Depending on your personal and family medical history, your doctor may recommend estrogen in the lowest dose needed to provide symptom relief for you.
Low-dose antidepressants. Venlafaxine (Effexor), an antidepressant related to the class of drugs called selective serotonin reuptake inhibitors (SSRIs), has been shown to decrease menopausal hot flashes. Other SSRIs can be helpful, including fluoxetine (Prozac, Sarafem), paroxetine (Paxil, others), citalopram (Celexa) and sertraline (Zoloft).
Gabapentin (Neurontin). This drug is approved to treat seizures, but it also has been shown to significantly reduce hot flashes.
Clonidine (Catapres, others). Clonidine, a pill or patch typically used to treat high blood pressure, may significantly reduce the frequency of hot flashes, but unpleasant side effects are common.
Bisphosphonates. Doctors may recommend these nonhormonal medications, which include alendronate (Fosamax), risedronate (Actonel) and ibandronate (Boniva), to prevent or treat osteoporosis. These medications effectively reduce both bone loss and your risk of fractures and have replaced estrogen as the main treatment for osteoporosis in women.
Selective estrogen receptor modulators (SERMs). SERMs are a group of drugs that includes raloxifene (Evista). Raloxifene mimics estrogen's beneficial effects on bone density in postmenopausal women, without some of the risks associated with estrogen.
Vaginal estrogen. To relieve vaginal dryness, estrogen can be administered locally using a vaginal tablet, ring or cream. This treatment releases just a small amount of estrogen, which is absorbed by the vaginal tissue. It can help relieve vaginal dryness, discomfort with intercourse and some urinary symptoms.

Before deciding on any form of treatment, talk with your doctor about your options and the risks and benefits involved with each.

Non-pharmaceutical therapies

In women for whom oral or vaginal estrogens are deemed inappropriate, such as breast cancer survivors, or women who do not wish to take oral or vaginal estrogen, there are a variety of over-the-counter vaginal lubricants. However, they are probably not as effective in relieving vaginal symptoms as replacing the estrogen deficiency with oral or local estrogen.

Lifestyle factors in controlling the symptoms and complications of menopause

Many of the symptoms of menopause and the medical complications that may develop in postmenopausal women can be lessened or even avoided by taking steps to lead a healthy lifestyle. Regular exercise can help protect against cardiovascular disease as well as osteoporosis, and exercise also has known mental health benefits. Proper nutrition and smoking cessation will also reduce your risk of cardiovascular disease

REFERENCES:

Newton KM; Reed SD; LaCroix AZ et al. Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial. Ann Intern Med. 2006 Dec 19;145(12):869-79.

Rossouw JE; Anderson GL; Prentice RL et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial. JAMA 2002 Jul 17;288(3):321-33.

Utian WH; Archer DF; Bachmann GA, et al. Estrogen and progestogen use in postmenopausal women: July 2008 position statement of The North American Menopause Society. Menopause. 2008 Jul-Aug;15(4 Pt 1):584-602.

Previous contributing authors and editors:
Carolyn Janet Crandall, MD, FACP and Dennis Lee, MD