Menopause & the Menstrual Cycle
My clients frequently ask me, “How long does perimenopause last?”. It is an important question, especially for those experiencing menopausal symptoms who want to know when they are likely to end.
Unfortunately, there is no definitive answer, as everyone experiences the menopausal transition differently. However, there are some clues we can look out for that may give us a hint as to where we are in our journeys. Many of these lie in our menstrual cycles.
Read on to learn more about menstrual cycles and menopause, and the changes we might expect to see along the way.
Phases of the Menstrual Cycle
Before we dive into how menopause affects menstrual cycles, I will briefly summarise the different phases of the menstrual cycle and the key hormones involved in each one.
Menstrual cycles are measured from the first day of bleeding (Day 1) and typically last around 28 days, although cycles ranging from 21 to 35 days can be considered normal. Some people experience regular cycles for most of their reproductive years, while others have more irregular periods.
The menstrual cycle can be divided into two halves, the follicular phase and the luteal phase. They are separated by ovulation, which typically occurs on Day 14 of a 28-day cycle.
Follicular Phase
During the follicular phase, follicle-stimulating hormone (FSH) and oestrogen levels steadily rise as a dominant follicle is selected and begins to mature. Follicles are tiny structures on the ovaries that contain oocytes (egg cells), and as they mature, these cells develop into an ovum (egg) to be released at ovulation.
In Chinese medicine, this is known as the yin phase, and in the popular “inner seasons” model, it represents spring. It typically involves a steady increase in energy and is often seen as a good time to plan projects and begin new enterprises.
Ovulation
At ovulation, the pituitary gland releases a surge of luteinising hormone (LH). FSH and oestrogen levels peak simultaneously. This burst of hormones causes the follicle to release its ovum, resulting in ovulation.
At this time, the body temperature rises significantly, and this is often used as a marker of ovulation. Many people also notice a change in their cervical mucus, which tends to become copious, clear, and stretchy prior to ovulation. At this stage of the menstrual cycle, fertility peaks.
In Chinese medicine, this is known as the yang phase, and in the inner seasons model, it represents summer. It typically involves an increase in social and sexual energy, and many people feel they are at their peak performance during ovulation.
Luteal Phase
After ovulation, FSH, LH, and oestrogen levels fall. After releasing its ovum, the follicle shrivels to become what is known as a corpus luteum, or “yellow body.” The corpus luteum secretes progesterone, a hormone that supports pregnancy, should it occur. This coincides with the endometrium (the lining of the uterus) thickening, in preparation for a possible pregnancy.
Progesterone levels peak around Day 21 of a 28-day cycle, accompanied by a second smaller rise in oestrogen levels. If pregnancy does not occur, the secretion of these hormones reduces steadily from Day 21 to Day 28.
In Chinese medicine, this is known as the qi phase, and in the inner seasons model, it represents autumn. It is a time that requires gentle movement as we wind down and prepare to bleed. It is also when many people experience qi stagnation, resulting in pre-menstrual symptoms.
Menstruation
If pregnancy has not occurred, progesterone production ceases and the endometrium sheds, resulting in menstrual bleeding. The length of this phase is highly variable, as is the colour and volume of menstrual blood produced. Bleeds between five and seven days are most common.
In Chinese medicine, this is known as the Blood phase, and in the inner seasons model, it represents winter. It is a time that requires both rest and nourishment so we can replenish ourselves, ready for the next cycle to begin.
Cycle Changes During Perimenopause
The word “menopause” is technically defined as the time point 12 months after the final menstrual period. Many people notice menstrual cycle changes as they approach menopause, and traditionally, this has been used as a predictor of when menopause will occur.
However, many people never experience regular menstrual cycles, and numerous factors can affect the frequency, duration, and characteristics of our bleeds. Therefore, this is no longer considered a particularly accurate method.
That said, there are some subtle clues that might suggest menopause is in sight. For example, a study of 511 women found that cycle length remained fairly stable until four years before the final menstrual period, at which point it tended to become longer. This coincided with a reduction in evidence of luteal activity, suggesting that ovulation occurred less often as the women approached menopause (anovulation).
Another study of 804 women found that anovulation was associated with both shorter (under 21 days) and longer (over 36 days) menstrual cycles. Furthermore, the study suggested that anovulation could result in short (1-3 days) and long (8+ days) durations of menstrual bleeding.
However, heavy bleeding was not associated with anovulation and was more likely to occur in obese participants or those with uterine fibroids. Therefore, significant changes in cycle length and bleeding duration may be more accurate ways to predict the approach of menopause than the heaviness of bleeding.
The Stages of Reproductive Ageing
In 2011, a new framework was developed to define the stages of reproductive ageing. Known as the STRAW 10+ criteria, this was intended to be a more accurate and inclusive way to understand the hormonal and physical changes that occur during the pre-, peri-, and post-menopausal periods.
The criteria provide a numerical “timeline,” beginning with the onset of menstruation (-5) and ending with the late post-menopausal period (+2). The final menstrual period occurs at zero. The stages relevant to the peri- and post-menopausal periods are summarised below:
Stages -3b/-3a (Late Reproductive Phase)
FSH and oestrogen levels start to become variable
Menstrual cycles remain regular or become slightly irregular
Occasional menopausal symptoms are possible
Pregnancy is still possible
Stage -2 (Early Perimenopause)
FSH and oestrogen levels remain variable
Menstrual cycles become increasingly irregular
Menopausal symptoms become more likely
Pregnancy is still possible
Stage -1 (Late Perimenopause)
FSH levels rise
Oestrogen levels fall
Menstrual cycles lengthen, possibly to 60+ days
Menopausal symptoms are highly likely
Pregnancy is still possible, but unlikely
Final Menstrual Period (0)
The final menstrual period is identified retrospectively. It is measured from the first day of the last bleed preceding 12 consecutive months without a period (menopause).
Stages +1a,b,c, +2 (Postmenopausal Phase)
FSH levels remain elevated
Oestrogen levels remain low
Menstruation ceases
Menopausal symptoms become more variable
Pregnancy is not possible
The risk of chronic medical conditions increases
Menopause and Menstrual Cycles: Summary
Menstrual cycles tend to become increasingly irregular throughout the perimenopausal period until they eventually cease at menopause. For some people, noticing cycle changes can be a helpful predictor of menopause approaching. However, it is not entirely accurate, and hormonal changes and the frequency and intensity of symptoms should be considered too.
Unfortunately, there is no unequivocal way to estimate precisely when menopause will occur. Nonetheless, paying attention to our cycles and noting any changes can be a beneficial exercise, not only for these purposes but also to try to find patterns in how we feel and behave during different phases of our menstrual cycles.
This can help us to understand fluctuations in our emotions and energy levels, plan our activities more effectively, and remind us to give ourselves care and nourishment when it is most needed.
To learn more about how menopause influences our hormones and how to manage symptoms effectively, check out my Embracing Menopause online course.