What are the stages of menopause? Let’s get clear about this transition

If you've ever searched "what are the stages of menopause?" you've probably already found a fairly standard answer. Perimenopause, menopause, post-menopause. Done.

And while that's technically correct, it leaves out something that I consider to be just as important as the clinical definition. Something that most women are never told, and that can change everything about how they understand their own experience.

So in this post, I want to give you the complete picture. The medical facts, clearly explained. The timeline, broken down. And, crucially, the part of this conversation that is still being missed: that the menopause transition can start far earlier than most women expect, and that some women move through it without ever knowing it's happening.

Let's start from the beginning.

What is menopause, exactly?

First, a definition worth getting right.

Menopause is not a phase. It is a single point in time. Specifically, the moment that marks 12 consecutive months without a period. Your GP will confirm menopause once that 12-month threshold has been reached.

Before that point, you are in perimenopause. After it, you are in post-menopause.

Menopause marks the end of your menstrual cycle. It happens when your ovaries stop releasing eggs and oestrogen production drops significantly. Unlike the other stages, menopause is a single event rather than an ongoing phase.

The average age of menopause in the UK is 51. But as we'll come to, that average tells only part of the story.

The stages of menopause explained

Stage 1: Perimenopause

The transition often lasting 4 to 10 years

Perimenopause is the stage most women actually mean when they say they are "going through menopause." It is the transitional period during which the ovaries gradually produce less oestrogen and progesterone, and it is where the vast majority of symptoms occur.

Perimenopause can begin as early as 10 years before menopause. Most women reach menopause around age 51, but perimenopause often begins in their 40s. During this stage, the ovaries produce less oestrogen and progesterone, which can cause an array of ‘common’ menopause symptoms such as hot flushes, night sweats, joint pain and changes in mood.

But it's not just physical. The emotional and cognitive symptoms of perimenopause are just as real and far less talked about. Women navigating this stage often describe:

• Loss of confidence and a sudden increase in self-doubt

• Anxiety and low mood that feels disproportionate or hard to explain

• Brain fog, memory difficulties, and difficulty concentrating

• Disrupted sleep and profound fatigue

• Emotional reactivity and sensitivity that feels unlike themselves

• A shifting sense of identity and not quite knowing who they are anymore

  
  

Early in the menopausal transition, menstrual cycle lengths can becomes variable, with intervals differing by 7 or more days between cycles. Progressive changes during this stage may lead to episodes of amenorrhoea (the absence or lack of menstrual periods) lasting 60 or more days. Development of such prolonged amenorrhoea signals entry into the late menopausal transition stage, which typically occurs one to three years before the final menstrual period.

In other words, perimenopause is not a single, uniform experience. It has its own early and late phases, and the late stage, where the hormonal drop accelerates, is often when symptoms intensify most.

What many women don't realise: perimenopause can begin in the mid-30s. Some women notice the first changes such as subtle shifts in mood, energy, cycle length in their late 30s, often without any awareness that hormones could be involved. This is one of the most significant gaps in how we currently talk about this transition.

Stage 2: Menopause

A single moment, not a phase

As mentioned, menopause itself is the 12-month marker. Once you have gone 12 consecutive months without a period, menopause has occurred.

Menopause is diagnosed after 12 months of amenorrhoea. Hormonal changes and clinical symptoms occur over a period leading up to and immediately following menopause. This period is frequently termed climacteric but is increasingly referred to as the menopausal transition.

It is worth knowing that in the absence of a blood test, the diagnosis of menopause can only be made retrospectively, which is why women are often unsure whether they have "reached" menopause while they are in the midst of it. If you are still having occasional periods, even infrequent ones, you are still technically in perimenopause.

Stage 3: Post-menopause

The rest of your life after menopause

Post-menopause is the stage following menopause. It can last until the end of life.

This stage is defined not by symptoms but by the passage of time since the final period. Many women find that the more acute symptoms of perimenopause such as hot flushes, sleep disruption, extreme mood changes can begin to ease in postmenopause, as the body gradually adjusts to its new hormonal baseline.

However, post-menopause comes with its own health considerations. Lower oestrogen levels over the long term affect bone density, cardiovascular health, and cognitive function which is why ongoing medical support and awareness remain important well beyond the transition itself.

Early post-menopause includes several substages following the final menstrual period, the first of which encompasses the 12 months following that final period.

The part most guides leave out: early and premature menopause

Here is where the standard "three stages" answer becomes inadequate and where I want to spend some time, because this is the part of the conversation that is still not reaching the women who need it most.

Early menopause

The average age a woman experiences menopause in the UK is 51 years. However, many women have an earlier menopause. If you are under 45, it is referred to as an early menopause. Around 5 in 100 people enter menopause between the ages of 40 and 44.

That is 5% of women, a significant proportion of the female population. Reaching menopause while many are still building careers, trying for families, and navigating the most demanding years of their lives.

I know this firsthand. I was diagnosed with early menopause at 41. By the time I received that diagnosis, I had spent years not understanding what was happening to me like the anxiety, the loss of confidence, the feeling that I was losing myself, without anyone connecting those experiences to my hormones.

Premature Ovarian Insufficiency (POI)

If you are under 40, your condition is referred to as Premature Ovarian Insufficiency (POI). POI occurs when your ovaries no longer work properly under the age of 40. Your ovaries no longer produce normal amounts of oestrogen and therefore may not produce eggs, causing periods to stop or become irregular.

Premature Ovarian Insufficiency affects about 1 in 100 people which means the early loss of ovarian function in patients before the age of 40. Sometimes the function of the ovaries may come back intermittently, causing the return of periods and ovulation.

POI is more common than you may expect, affecting approximately 1 in 10,000 people before the age of 20, 1 in 1,000 before the age of 30, and 1 in 100 before the age of 40. However, recognising POI can be delayed or missed.

That last point matters enormously. Delayed and missed diagnosis is one of the defining features of both early menopause and POI. Women are told they are too young. Their symptoms are attributed to stress, anxiety, or depression. They are given antidepressants when they needed hormonal support, and they spend months, sometimes years not understanding what is happening to them.

Induced menopause

There is a fourth type of menopause that rarely features in general guides, but which affects a significant number of women: induced menopause. This occurs when the ovaries are removed surgically (oophorectomy), or when ovarian function is damaged or stopped by chemotherapy, radiotherapy, or certain medications.

Iatrogenic menopause can be caused by bilateral oophorectomy, chemotherapy or radiotherapy-induced ovarian failure, or other pharmacological treatments resulting in ovarian insufficiency.

Induced menopause typically causes a sudden and significant hormonal drop, often producing more acute symptoms than a gradual natural menopause. Women who experience induced menopause (often as a result of cancer treatment or gynaecological surgery) frequently report being unprepared for the emotional and psychological impact alongside the physical changes.

Why the average age is misleading

The average age of menopause in the UK is 51. This figure is repeated so widely and so often that it has become the benchmark against which millions of women measure their own experience and against which millions of women find themselves falling outside the expected time frame.

When a woman in her late 30s begins experiencing anxiety she has never had before, or a woman at 42 notices her cycle changing and her confidence disappearing, the thought that menopause could be involved rarely crosses her mind. Or her doctor's mind. Because the conversation has been built around 51.

The result is women who spend years misunderstood, misdiagnosed, and largely alone in an experience that is, in fact, far more common than they have been led to believe.

Understanding that the menopause transition is a spectrum; one that can begin in the 30s, that can arrive at 41, that affects around 5% of women before the age of 45 and 1% before 40; is not just medically useful. It is the thing that finally allows women to make sense of their

own story.

The emotional and identity dimension which is what the clinical stages don't capture

Reading a list of the stages of menopause gives you a framework. But it doesn't tell you what this transition actually feels like.

What the clinical stages don't fully capture is that this is not just a hormonal shift. For many women, it is an identity shift. A period of profound internal change that touches who they are, how they see themselves, and what they believe about their own worth, capability, and future.

Many women describe feeling like they no longer recognise themselves. Their confidence disappears. Their inner critic gets louder. The emotional regulation that used to feel manageable suddenly doesn't. And because no one is talking about menopause in this way, with honesty, with depth, with an acknowledgement of the psychological weight of this transition, women internalise it. They blame themselves. They assume something is wrong with them, rather than understanding that something is happening to them.

This is why I believe emotional and psychological preparation for the menopause transition is as important as physical preparation. Knowing what is coming and having support that addresses the whole experience - not just the symptoms - changes everything.

When to speak to your GP

If you are experiencing symptoms that could be related to perimenopause or early menopause (regardless of your age) it is worth speaking to your GP. You do not have to wait until you are in your late 40s for this conversation to be relevant.

If you are under 45 and suspect early menopause, or under 40 and experiencing changes in your cycle alongside other symptoms, ask specifically about early menopause and POI. Blood tests measuring FSH (follicle-stimulating hormone) levels can help inform a diagnosis, though they are not always conclusive during perimenopause itself.

You know your body. If something feels different, that matters - at any age.

If you'd like support beyond the clinical picture

Understanding the stages is one thing. Navigating the emotional, psychological, and identity shifts that come with this transition is another. That is the work I do with women, helping them make sense of their experience, rebuild their confidence, and move through this transition without losing themselves in it.

If this post has resonated with you, whether you are trying to understand what is happening right now, or piecing together an experience that has already passed, I would love to connect.

You can find out more at jorennie.com, or book a free discovery call to talk about where you are.

Jo 🦋