For a life stage that every woman who lives long enough will go through, menopause remains astonishingly under-taught. Most of us pick up fragments from mothers, sisters, friends, or the occasional article, and end up with a patchwork of information that only becomes useful once we start noticing changes ourselves. Here is the version worth having earlier.
What Perimenopause Actually Is
Perimenopause is the transition leading up to menopause, when the ovaries gradually produce less oestrogen. It usually begins in the mid-40s but can start earlier, sometimes in the late 30s. The length varies from woman to woman, with an average of four to eight years.
During this time, oestrogen does not decline in a straight line. It fluctuates erratically, sometimes higher than usual, sometimes lower, which is why symptoms can feel unpredictable. Progesterone declines more steadily as ovulation becomes less consistent.
What Menopause Actually Is
Menopause itself is a single point in time. It is defined as the day that is exactly twelve months since your last period. In other words, you only know you have reached menopause looking backwards.
The average age of menopause is 51 in most Western populations, although it can happen naturally anywhere from the mid-40s to late 50s. Anything before 45 is considered early menopause. Anything before 40 is called premature ovarian insufficiency (POI), which affects around 1 in 100 women and warrants proper medical care, including replacement of the hormones the body would otherwise still be producing.
What Postmenopause Actually Is
Postmenopause is everything after the twelve-month marker. It is not a transition. It is the rest of your life, which for most women is around a third of it. Oestrogen levels stay low, and while some symptoms ease over time (hot flushes eventually settle for most women), others such as vaginal dryness and bone loss tend to progress unless addressed.
The Hormonal Picture
Two main hormones drive the changes of perimenopause and menopause. Oestrogen is produced mainly by the ovaries. It declines overall but fluctuates wildly in perimenopause, which is what causes many of the more unpredictable symptoms. Progesterone is produced after ovulation and declines earlier, as ovulation becomes less regular.
A third hormone often mentioned is FSH (follicle-stimulating hormone), which is produced by the brain to prompt the ovaries. FSH rises as the ovaries become less responsive, which is why raised FSH is sometimes used as a marker in blood tests. It is not reliable in perimenopause though, because levels fluctuate too much from cycle to cycle.
When It Becomes Useful to Speak to Someone
You do not need severe symptoms to seek support. Reasons to speak to a clinician include:
Periods becoming heavier, more painful, or dramatically irregular
Symptoms affecting your sleep, mood, work, or relationships
Any bleeding after 12 months without a period (this always warrants review)
Symptoms in your 30s or early 40s, when early menopause should be ruled out
Wanting to understand your options before symptoms become disruptive
Perimenopause is not a phase to endure quietly. It is a phase to understand. Knowing what stage you are in, and what is driving it, is where informed care begins.