Sometimes it is a lurching, stop and start process that takes years. It can affect a woman's hormones, body and feelings. For most women it will last two or three years, though for some it lasts as long as 10 or 12 years. The ovaries' production of estrogen slows down, making hormones fluctuate and causing attendant physical changes. While menopause usually occurs around age 50, it can happen earlier due to heredity, health conditions, exposure to radiation or chemotherapeutic agents, surgical removal of the ovaries, or any surgery which compromises blood flow to the ovaries.
Surgical menopause begins immediately, with no perimenopause.
It can be caused by emotional strain, chemotherapy, grief or illness. There are women who sail through menopause. Contrary to what you may have heard, they do exist. Scientific evidence proves it. The effects of menopause aren't limited to the reproductive organs.