What Happens

In your late 30s, your egg supply begins to decline in number and quality. As a result, your hormone production changes. You may notice a shortened menstrual cycle and some premenstrual syndrome (PMS) symptoms that you didn't have before.

Gradually, your periods become irregular. This can start as early as your late 30s or as late as your early 50s. It continues for 2 to 8 years before menstrual cycles end.

During this time, your ovaries are sometimes producing too much estrogen and/or progesterone and at other times too little. Your progesterone is likely to fluctuate more than before. This can lead to heavy menstrual bleeding. (If you have heavy or unexpected vaginal bleeding, see your doctor to be sure it isn't caused by a more serious condition.)

About 6 months to a year before your periods stop, your estrogen starts to drop. When it drops past a certain point, your menstrual cycles stop. After a year of no menstrual periods, you are said to have "reached menopause."

During the next year or so, estrogen levels keep going down. This lowers your risk for certain types of cancers (estrogen is linked to some types of cancerous cell growth). But low estrogen also creates some health concerns, such as:

• Bone loss. Low estrogen levels after menopause speed bone loss, increasing your risk of osteoporosis.
• Skin changes. Low estrogen leads to low collagen, which is a building block of skin and connective tissue. It's normal to have thinner, dryer, wrinkled skin after menopause. The vaginal lining and the lower urinary tract also thin and weaken. This condition can make sexual activity difficult. It can also increase the risk of vaginal and urinary tract infections.
• Tooth and gum changes. Low estrogen affects connective tissue, which increases your risk of tooth loss and possibly gum disease.²

Although the reasons aren't well understood, a woman's risk of heart disease increases after menopause. Because heart disease is the number one killer of women, consider your heart risk factors when making lifestyle and treatment decisions.