Menopause is a natural stage of a woman's life and marks the end of her fertility. The North American Menopause Society (NAMS) defines menopause as being the state a woman reaches when she does not have a menstrual period for more than a full calendar year. NAMS indicates that 51 years old is the average age of menopause. Early menopause is the term used when a woman's periods permanently stop "well before" before the age of 51, in NAMS' language. This is not to be confused with premature menopause, which occurs before a woman's fortieth birthday. Early menopause can be natural, called spontaneous, or it can be induced for several reasons.
Premature Ovarian Failure
Premature ovarian failure (POF) is the medical term given to the cessation of the ovaries' function when a woman is younger than 40 year old. The ovaries must be able to release mature eggs in order for the menstrual cycle to function and if a woman is to become pregnant. When the ovaries do not function any more, menopause is the result. The Mayo Clinic explains that spontaneous POF is often the result of hormonal imbalances or chromosomal defects. Environmental pollutants such as cigarette smoke or pesticides may also cause POF and, therefore, early menopause.
Medical Menopause
Cancer treatments such as chemotherapy and radiation can lead to early menopause. Chemotherapy drugs and radiation can be highly toxic to healthy parts of the body, including the ovaries. Treatments of this kind can cause a woman in her 20s or 30s to experience premature ovarian failure before age 40, and this leads to early menopause. The term for this form of induced menopause is called medical menopause.
Surgical Menopause
Some women in their 40s must undergo surgery that leads to early menopause. The two types of surgery that induce menopause at any age are a full hysterectomy, in which the uterus and the ovaries are removed, and an oophorectomy, an operation in which the ovaries are surgically removed. Uterine infections, fibroids and endometriosis are all situations that can require a woman to need one of these types of surgery. A women under the "typical" menopause age of 51 who only has her uterus removed and retains working ovaries is not considered to be in early menopause because the ovaries continue to produce hormones normally even when menstruation has stopped. When the ovaries cease the production of estrogen, menopause begins.
