We read and hear so much about menopause that you would think that the definition is straightforward, and it would be easy for a woman to know whether she’s experienced it or not. Not so. Menopause is a process, not an event.
Simply defined, menopause is when a woman stops having periods, signaling the end of her ability to have children. But women usually do not have regular periods that suddenly stop one day. There is a period of transition from regular periods to menopause, during which most women have irregular cycles. They may go one or more months without a period, then begin again.
So when can you be relatively certain that your periods have ended? Practically speaking, it’s the test of time. If you haven’t had a period for a year, chances are that you have gone through menopause. Having symptoms of menopause, such as hot flashes and/or vaginal dryness, supports this diagnosis. But these symptoms can occur before, during and after your last period.
In addition to the test of time, a blood test usually can verify if you are in menopause. An FSH test measures the level of a substance called follicle stimulating hormone, which tells the ovary to develop an egg and then release it into the fallopian tube where it will travel to the uterus, waiting for a sperm. An FSH greater than 40 is the generally accepted level at which a women is considered through perimenopause and in menopause.
The FSH test may be helpful for many women when they are considering hormone therapy for hot flashes. However, some women need hormone therapy to treat hot flashes and vaginal dryness even if they have normal FSH levels or still have an occasional period.
A group of reproductive researchers convened in 2001 at the Stages of Reproductive Aging Workshop (STRAW) to finalize recommendations for defining menopause and the stages before and after. The researchers concluded that the transition into menopause occurs first as periods change in length, then as you skip periods or have very heavy bleeding. Menopausal symptoms usually occur in the late stage of the transition.
Perimenopause is that transitional phase between the time periods become irregular and when one year has passed since the last menstrual period. This phase often lasts several years. In addition to irregular periods, women can experience hot flashes, vaginal dryness, and mental or psychological symptoms.
The postmenopause stage begins after your last period. But since you don’t know for sure it’s your last period until a year has passed, it is better to wait until twelve months after your last period to say you are postmenopausal. During those months between what you think is your last period it is better to think of yourself as in perimenopause.
The following table illustrates the various stages.
Source: Adapted from the Stages of Reproductive Aging Workshop
When I ask my female patients over the age of 50, “Have you gone through menopause, or the change of life?” I follow it up with, "When was your last period?" because some women don’t realize they are in the transition to menopause if they have irregular periods. Similarly, I ask women in their 40s if their periods are regular, and if they are having any symptoms.
If a woman believes she has gone through menopause and answers that her last period was less than one year ago, the next question is, "Are you having hot flashes, vaginal dryness, memory problems, irritability or mood changes?" If yes, she could be in the final months of transition to menopause and her last period. If no, she may or may not be in the transition to menopause. Either way, she should make sure to continue methods of birth control, as she can still get pregnant.
If a woman says her last period was more than a year ago, then she is postmenopausal. (But if you are a woman who never had regular periods and can skip almost a year, this may not apply to you.)
Why do we say that you can still get pregnant if you’re in menopause? Well, this usually means you are actually in the perimenopause. Although one month your hormone levels may be low, your ovary might make one last egg in the following month. If you don't have a period for a full year, you can feel quite confident that you will not get pregnant.
How ironic that you need to consider pregnancy while your body is sending signals of transition to a very different phase!
This transitional period is often called “change of life,” a term that resonates with many women and works well, given the way stages can overlap. Occurring at an average age of 51, menopause is often a time of life changes, physically, socially and emotionally. Your children may be leaving home; you may be promoted in your work life, contemplating retirement or working part time.
Menopause also marks a period of time when health risks increase, especially for heart disease, breast cancer and osteoporosis. If you are perimenopausal or postmenopausal it is important to see your health care professional to talk about ways to lower your risks and screen for the early signs of problems.
Alice Y. Chang, M.D. is a former instructor in medicine at Harvard Medical School. She is currently associated with University of Texas Southwestern Medical Center. Her clinical interests and experience are in the fields of primary care, women's health, hospital-based medicine and patient education.