Redrawing the map: Why the current menopause criteria may be outdated

The journey through menopause, a significant life stage marking the end of a woman's reproductive years, typically spans several years and includes distinct phases – late premenopause, perimenopause (early and late), and postmenopause.

Each phase is associated with a variety of symptoms, yet distinguishing between these stages has been challenging – especially for women who no longer menstruate in their late premenopausal years.

However, new research from Monash University challenges current clinical assumptions and is reshaping how we understand and identify these transitions, with profound implications for clinical care and women’s health.

The comprehensive study, recently published in The Lancet Diabetes & Endocrinology, has shed light on the menopausal transition. Involving 5509 women aged 40 to 69, the study provides a clearer clinical picture of how symptoms vary – and sometimes blur – across the stages.

According to lead researcher Professor Susan Davis, head of the Monash Women’s Health Research Program, vasomotor symptoms (VMS) that comprise hot flushes and night sweats are now shown to be the most defining characteristics of perimenopause.

These symptoms were found to be five times more prevalent in early perimenopause compared with premenopause.

Vaginal dryness, another often-overlooked symptom, was also highlighted as a significant marker – 2.5 times more likely in perimenopausal women than in premenopausal ones.

While other symptoms were observed, such as memory issues and low mood, they were less specific to perimenopause, with poor memory being only 1.7 and 1.3 times more likely in early and late perimenopause, respectively.

Read more: Menopause wars: How much treatment is too much?

“A major finding was that women with regular cycles yet have changed menstrual flow (heavier or lighter periods) and VMS, who are presently classified as premenopausal, had a similar severity of a wide range of symptoms as early perimenopausal women. This indicated these women should be considered clinically perimenopausal,” Professor Davis says.

“We already knew that VMS symptoms like hot flushes and night sweats were typical menopausal symptoms. However, our study clearly shows that a new onset of VMS is highly specific to perimenopause, being nearly five times more likely than in premenopause.

“While other symptoms might emerge in the perimenopausal stage, they lack specificity to that stage as other symptoms, such as poor memory.

“This study also suggests that classic VMS should be considered as a diagnostic criterion for perimenopause or postmenopause when menopause can’t be distinguished by the bleeding pattern. For example, after a hysterectomy, women with a hormonal IUD, or women with regular cycles,” she says.

“Additionally, women whose periods have become much heavier or much lighter and have VMS are likely to have started their perimenopause.”

A redefinition of perimenopause

The study calls for a redefinition of perimenopause that includes symptoms rather than menstrual bleeding patterns alone, in order to help identify when women whose bleeding patterns are unreliable or absent, such as after a hysterectomy or in women using a hormonal IUD, have reached perimenopause.

First author on the study, Dr Rakib Islam, from Monash University’s School of Public Health and Preventive Medicine, says:

“This study stands out for its national reach and methodological depth, linking clearly-defined menopausal stages with validated symptom profiles in more than 5500 women. This level of detail is essential to improve how we identify and manage the menopause transition.

“Current approaches for classifying women by menopause stage overlook women with regular cycles and women who no longer menstruate, for example, after a hysterectomy.

“Our findings support a more symptom-based approach, enabling earlier recognition of perimenopause and more timely care,” Dr Islam says.

The stages of menopause

Premenopause

This stage encompasses the years of regular menstrual cycles, with hormonal fluctuations aligning with each menstrual cycle phase.

Perimenopause

This transitional phase leading up to the menopause can last several years. This is presently defined as occurring when menstrual cycle length varies by at least seven days. Women typically experience increasing menopausal symptoms such as hot flushes, night sweats, low mood, and sleep disturbances.

Perimenopause is often divided into:

• Early perimenopause: Menstrual cycles vary in length (shorter or more spaced apart) by at least seven days. Hormone levels start to become more erratic.

• Late perimenopause: At least two to three months between menstrual bleeds. Hormone levels remain erratic, with estradiol levels fluctuating from very high to very low.

3. Postmenopause
   The time after the final menstrual period. The final menstrual period is not defined as such until a woman hasn’t had a menstrual bleed for at least 12 months. The production of estrogen and progesterone by the ovaries is minimal. Some symptoms, such as vasomotor symptoms, may persist for years, while others, such as vaginal dryness, may worsen with years post-menopause due to prolonged estrogen deficiency.

Professor The Hon Jill Hennessy, Chair of Monash Women's Health Alliance said: “This landmark study reinforces just how critical it is to listen to women and take their symptoms seriously. Too many go untreated for debilitating symptoms like hot flushes and night sweats. Research like this is essential to ensure women get the timely, evidence-based care they deserve during perimenopause.”  

“Menopause is a major women’s health issue that has been overlooked for too long. By defining the symptoms that truly mark this transition, this study empowers women and clinicians alike with better knowledge and tools to improve women’s health and wellbeing.”