A woman is through menopause when she had not menstruated for one full year. On average, according to the National Institute on Aging, this occurs at age 51. The symptoms of menopause might begin before or during the year before the last period, a time often called peri-menopause, and they might be minor or last for several years.
Diagnosing Menopause
Lab Tests Online describes how laboratory testing can help determine if a woman is menopausal. One test measures a type of estrogen called estradiol. When estradiol falls below 36, a woman is most likely in menopause. Another test, called an FSH, for follicle stimulating hormone, also might be run. FSH is a signal from the brain to the ovary, asking the ovary to make estrogen. When less estrogen is being produced, the FSH level rises. Above a level of 30 to 40mIU/mL (micro International Units per microliter), menopause is likely.
Early Menopause
Menopause that occurs before age 40 is called premature menopause, and it is usually caused by surgical removal of the uterus and ovaries, called a total hysterectomy, illness, genetics or medication. Menopause after age 40 but before age 51 is considered normal.
Health Considerations in Early Menopause
By shortening the number of years during which the body is exposed to high levels of estrogen, early menopause can reduce the risk of hormone-sensitive cancers, such as breast, ovarian and colorectal cancer. The risk of osteoporosis, however, is higher in women who have had premature menopause. The Women's Health division of the U.S Department of Health and Human Services cautions that premature menopause, especially when brought on suddenly by surgery or medication, can cause severe symptoms, such as insomnia, hot flashes and mood changes.
Late Menopause
Age 51 is the average age of menopause for women, but it can take a woman until her late 50s to complete the change to post-menopausal. Menopause is considered late when it occurs after age 55, which may occur in overweight women or women with uterine fibroids. Although less common than early menopause, a study by Norwegian researchers that was published in 2003 in the "American Journal of Epidemiology" found that late menopause is moderately related to a decrease in deaths from all causes.
Health Considerations in Late Menopause
According to Gabe Mirkin, M.D., the presence of estrogen late in a woman's life has been found to extend her lifespan. Estrogen enhances bone density and the thickness of skin, protecting her from falls. Although there might be an increased risk of breast cancer from the extended years of estrogen exposure, the risk of cardiovascular disease is reduced by late menopause.
References
- US National Institutes of Health. National Institute on Aging: Age Page: Menopause.
- Lab Tests Online. Menopause: Tests
- Department of Health and Human Services: Women's health: Understanding Menopause
- Dr. Mirkin.com: Late Menopause Associated with Longevity
- "American Journal of Epidemiology"; Age at Natural Menopause and All-Cause Mortality: A 37 year follow-up of 19,731 Norwegian women; Jacobsen BK, et al. 2003; 157(10):923-929.
