Menopause is a normal condition that all women experience as they age. The term “menopause” is commonly used to describe any of the changes a woman experiences either just before or after she stops menstruating, marking the end of her reproductive period.
What Causes Menopause?
A woman is born with a finite number of eggs, which are stored in the ovaries. The ovaries also produce the hormones estrogen and progesterone, which regulate menstruation and ovulation. Menopause occurs when the ovaries no longer release an egg every month and menstruation stops.
Menopause, when it occurs after the age of 40, is considered a normal part of aging. But some women can experience menopause early, either as a result of surgery, such as hysterectomy, or damage to the ovaries, such as from chemotherapy. Menopause that occurs before the age of 40, regardless of the cause, is called premature menopause.
How Does Natural Menopause Occur?
Natural menopause is the permanent ending of menstruation that is not brought on by any type of medical or surgical treatment. For women undergoing natural menopause, the process is gradual and is described in three stages:
- Perimenopause. Perimenopause typically begins several years before menopause, when the ovaries gradually produce less estrogen. Perimenopause lasts up until menopause, the point when the ovaries stop releasing eggs. In the last one to two years of perimenopause, the decrease in estrogen accelerates. At this stage, many women experience menopause symptoms (see below).
- Menopause. Menopause is the point when it’s been a year since a woman last had her last menstrual period. At this stage, the ovaries have stopped releasing eggs and producing most of their estrogen.
- Postmenopause. These are the years after menopause. During this stage, menopausal symptoms, such as hot flashes, ease for most women. However, health risks related to the loss of estrogen increase as the woman ages.
What Conditions Cause Premature Menopause?
Premature menopause can be the result of genetics, autoimmune disorders, or medical procedures. Other conditions that may cause early menopause include:
- Premature ovarian failure. Normally, the ovaries produce both estrogen and progesterone. Changes in the levels of these two hormones occur when the ovaries, for unknown reasons, prematurely stop releasing eggs. When this happens before the age of 40, it is considered to be premature ovarian failure. Unlike premature menopause, premature ovarian failure is not always permanent.
- Induced menopause. “Induced” menopause occurs when the ovaries are surgically removed for medical reasons, such as uterine cancer or endometriosis. Induced menopause can also result from damage to the ovaries caused by radiation or chemotherapy.