Other changes also occur at this time. Most women experience menopause between the ages of 45 and 55. The average is around 51. Cigarette smokers tend to reach menopause earlier than nonsmokers. Premature menopause may happen naturally, or it may be caused by another medical condition, injury to the ovaries, or surgery.
Natural menopause occurs when the body's production of sex hormones declines dramatically.
Ovulation and menstruation no longer occur. After menopause, the adrenal glands continue to produce androstenedione, which is converted in fat cells to a form of estrogen called estrone. Because obese women have more fat, they may produce more estrone, resulting in fewer menopausal symptoms. The levels of two other hormones, progesterone and testosterone, also drop at this time. Menopause can also occur as the result of disease, injury, or surgery.