In the months or years leading up to menopause (perimenopause), you might experience these signs and symptoms:

• Irregular periods
• Vaginal dryness
• Hot flashes
• Chills
• Night sweats
• Sleep problems
• Mood changes
• Weight gain and slowed metabolism
• Thinning hair and dry skin
• Loss of breast fullness

Symptoms, including changes in menstruation, are different for every woman. Most likely, you'll experience some irregularity in your periods before they end.

Skipping periods during perimenopause is common and expected. Often, menstrual periods will skip a month and return, or skip several months and then start monthly cycles again for a few months. Periods also tend to happen on shorter cycles, so they are closer together. Despite irregular periods, pregnancy is possible. If you've skipped a period but aren't sure you've started the menopausal transition, consider a pregnancy test.

Menopause can result from:

• Natural decline of reproductive hormones. As you approach your late 30s, your ovaries start making less estrogen and progesterone — the hormones that regulate menstruation — and your fertility declines. In your 40s, your menstrual periods may become longer or shorter, heavier or lighter, and more or less frequent, until eventually — on average, by age 51 — your ovaries stop producing eggs, and you have no more periods.
• Hysterectomy. A hysterectomy that removes your uterus but not your ovaries usually doesn't cause immediate menopause. Although you no longer have periods, your ovaries still release eggs and produce estrogen and progesterone. But surgery that removes both your uterus and your ovaries (total hysterectomy and bilateral oophorectomy) does cause immediate menopause. Your periods stop immediately, and you're likely to have hot flashes and other menopausal signs and symptoms, which can be severe, as these hormonal changes occur abruptly rather than over several years.
• Chemotherapy and radiation therapy. These cancer therapies can induce menopause, causing symptoms such as hot flashes during or shortly after the course of treatment. The halt to menstruation (and fertility) is not always permanent following chemotherapy, so birth control measures may still be desired.
• Primary ovarian insufficiency. About 1 percent of women experience menopause before age 40 (premature menopause). 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 can be found. For these women, hormone therapy is typically recommended at least until the natural age of menopause in order to protect the brain, heart and bones.

After menopause, your risk of certain medical conditions increases. Examples include:

• Heart and blood vessel (cardiovascular) disease. When your estrogen levels decline, your risk of cardiovascular disease increases. Heart disease is the leading cause of death in women as well as in men. So it's important to get regular exercise, eat a healthy diet and maintain a normal weight. Ask your doctor for advice on how to protect your heart, such as how to reduce your cholesterol or blood pressure if it's too high.
• Osteoporosis. This condition causes bones to become brittle and weak, leading to an increased risk of fractures. During the first few years after menopause, you may lose bone density at a rapid rate, increasing your risk of osteoporosis. Postmenopausal women with osteoporosis are especially susceptible to fractures of their spine, hips and wrists.
• Urinary incontinence. As the tissues of your vagina and urethra lose elasticity, you may experience frequent, sudden, strong urges to urinate, followed by an involuntary loss of urine (urge incontinence), or the loss of urine with coughing, laughing or lifting (stress incontinence). You may have urinary tract infections more often.

Strengthening pelvic floor muscles with Kegel exercises and using a topical vaginal estrogen may help relieve symptoms of incontinence. Hormone therapy may also be an effective treatment option for menopausal urinary tract and vaginal changes which can result in urinary incontinence.

• Sexual function. Vaginal dryness from decreased moisture production and loss of elasticity can cause discomfort and slight bleeding during sexual intercourse. Also, decreased sensation may reduce your desire for sexual activity (libido).

Water-based vaginal moisturizers and lubricants may help. If a vaginal lubricant isn't enough, many women benefit from the use of local vaginal estrogen treatment, available as a vaginal cream, tablet or ring.

• Weight gain. Many women gain weight during the menopausal transition and after menopause because metabolism slows. You may need to eat less and exercise more, just to maintain your current weight.