What Is The Difference Between Pre-menopause, Perimenopause, Menopause, And Post-menopause?
Pre-menopause is most commonly used to describe a woman’s reproductive phase when she is having periods regularly and ovulating. It’s when she has the best chance to become pregnant. (Studies put peak fertility at around 26.) It is also sometimes used more broadly to describe any time before a woman reaches menopause. In this way, it is sometimes used interchangeably with perimenopause. Because we’ve seen it used to describe so many different phases, we think it’s confusing, and we don’t use it on our site.
Perimenopause is a word with at least three definitions. Most generally, it’s used to describe the time leading up to menopause when hormonal patterns start to shift and fluctuate. The majority of healthcare providers would say a woman is “in perimenopause” when her cycles are of irregular lengths or she’s skipped a period. According to a framework used by the research community, the menopausal transition (aka perimenopause) begins when consecutive cycle lengths persistently vary by 6 or more days. Here, persistence is defined as at least 2 times in 12 months. We know from research that many women experience changes and symptoms associated with hormonal fluctuations before this point — when cycles are still coming every month. Through the information on this site and new research with collaborators, we are working to get more people to recognize this.
Menopause is the point at which a woman has gone 12 months without a menstrual period. It is identified retrospectively ( i.e. in hindsight) and marks the end of the reproductive years. The average age of menopause in the U.S. is 51.2 years, but onset varies significantly. The most common range is between ages 48 and 55, though a woman can have her last period anywhere between 40 and 60 and still be considered within the normal range.
Post-menopause is a term used to describe the years after a woman has reached menopause.
The menopausal transition is a term we will use to describe the phase when women’s hormones are changing during the many-year path to menopause. We break this into two phases:
A first phase when periods are coming monthly, but cycle length — the time between day 1 of flow (i.e. bleeding) of one cycle and day 1 of flow of the following — is shortening.
A second phase when cycles are more irregular and periods are skipped. A graphical depiction of that is here.
The graphic below illustrates how many different terms are used to describe these phases.
- It is a WLB perspective that both the “regular phase” and the “irregular phase” are both part of the menopausal transition. According to a research framework the menopausal transition doesn’t begin until cycles lengths change significantly.
- We think it’s important to validate people’s change in experience (aka new symptoms) before cycles are irregular. We are working to share this idea broadly.
Will My Mother’s Age At Menopause Give A Good Approximation Of Mine?
While some studies demonstrate this link, others don’t. There are many factors that influence the age of menopause. The single most influential factor was found to be smoking, which causes menopause to begin 1-2 years earlier than in non-smokers.
This paper, “The Timing of the Age at Which Natural Menopause Occurs,” gives a very detailed overview of the many possible influences on the age of menopause.
What Causes Hormonal Changes To Start?
Changing hormones are a normal part of the natural aging process. The beginning of the changes is triggered when a woman’s declining egg reserve reaches a low level. At this point, the rate of decline of eggs increases. This is around age 37-38.1
What Are The Earliest Signs That You Are In The Menopausal Transition?
Usually, the first sign of these changes is a slight shortening of the menstrual cycle by a couple of days. For example, if you used to get your period every 29 days during your 20s and 30s, you may notice that your cycle shortens to an average of 27 days. For many women, this change is imperceptible, especially if they don’t track their periods. The decline is not obvious month after month. See examples from our cycles here.
Do All Women Experience Symptoms?
No! Not all women experience symptoms, but many do. And we suspect that most women do, but the fact that it is under-acknowledged and under-discussed by both women and healthcare providers alike masks a higher incidence of symptoms. Estimates as to what percent of women experience symptoms vary very widely in the research and literature. We hope to collect data through this website to spur research that might uncover a more accurate picture.
What Is The Women’s Health Initiative (WHI)?
The Women’s Health Initiative (WHI) is the name of a group of studies initiated in 1991 to explore major health issues causing morbidity and mortality in postmenopausal women, specifically cardiovascular disease, cancer, and osteoporosis.2
Prior to the WHI, most studies of disease were conducted in men. In the 1980s, it had become apparent that past biomedical research had focused disproportionately on white men, often neglecting prevention and treatment studies of diseases that are either unique to or more common in women and minorities. In 1985, the Public Health Service Task Force on Women’s Health Issues issued recommendations that biomedical and behavioral research should be expanded to provide for the inclusion of diseases and conditions identified among women of all age groups. In 1986, the NIH issued recommendations that women be included in all research studies. To further promote the study of women, in 1990, the NIH created the Office of Research on Women’s Health.1
The WHI study actually had four different treatment groups:
- Dietary modification
- Hormone therapy: estrogen and progestin
- Hormone therapy: estrogen alone
- Calcium and vitamin D
When you hear the term “WHI study,” it is almost always in reference to the hormone therapy (HT) arm of the larger trial. These treatment groups looked at whether HT had preventative health benefits for women. These parts of the study were the first randomized, controlled studies to examine the hormones that had been prescribed to women for so many years.
In 2002, the study was halted after early results showed an increase in cancer and cardiovascular disease. Results did show a decrease, as expected, in hip fractures (a measure for osteoporosis).
There is a chart of the findings by treatment group on Wikipedia (scroll down to the section called “Study components and primary findings”).
You can also find more information on the history of hormone therapy here.
What is Compounding and Is It Safe?
Compounding is the process of creating a medicine tailored for a specific patient by mixing an active pharmaceutical ingredient (API) with other ingredients (excipients). A compounding pharmacist creates compounded products based on a prescription from a medical provider.
There is much debate in the medical community about the safety of compounded products, since they are not regulated by the FDA. The individual ingredients used are FDA-approved, but the ratio in which they are mixed and the process by which they are combined are not. So there are often concerns over whether the exact same amount of active ingredient is present across doses. In addition, there have been public scares — the most recent in October 2012 — about contaminated steroid injections from compounding pharmacies. This is often cited as a reason for concern about compounded hormone therapy.
Since the scare mentioned above, two measures have been put in place to increase safety: 1) the government passed the Drug Quality and Safety Act in November of 2013 and 2) the FDA created additional mechanisms for communication with State Boards of Pharmacy to put in place increased oversight and guidelines.
For more information about compounding, click here.
Is There A Difference Between Hormone Therapy, Hormone Replacement Therapy and Menopausal Hormone Therapy?
No. Note this has had to be updated as terms are ever volving. Menopausal Hormone therapy (MHT) is the term du jour. The word “menopausal” was added so as to differentiate these therapies from say insulin or thyroid therapies which are also hormonal therapies. When we launched this website in 2018, hormone therapy (HT) was the term du jour for the practice of treating menopausal symptoms with hormones. In the past, the term used was hormone replacement therapy (HRT), but many take issue with the idea of replacing hormones since a woman’s hormones are meant to decline as part of the natural aging process and what’s added back through therapy is usually a very small amount, not a full replacement. Other terms we’ve seen used are menopause therapy and ovarian therapy.
More definitions and more on hormone therapy here.
REFERENCES
1. Karl R. Hansen, Nicholas S. Knowlton, Angela C. Thyer, Jay S. Charleston, Michael R. Soules, Nancy A. Klein. A new model of reproductive aging: The decline in ovarian non-growing follicle number from birth to menopause. Human Reproduction, volume 23, issue 3, March 1, 2008, pages 699–708.
2. Wikipedia.