Menopause occurs when you haven't had a menstrual period in 12 consecutive months. During perimenopause, hormone production by the ovaries decreases and a woman loses the ability to conceive.

Perimenopause usually occurs between ages 45 and 55, though the center says it may happen as early as the 30s. Symptoms of perimenopause include changes in menstruation, hot flashes and night sweats, insomnia, irritability, changes in mood and changes in hair growth.

Eating a healthy diet, getting regular exercise and practicing stress-management techniques can help some women cope with symptoms of perimenopause, according to the center.

-- Diana Kohnle