Understanding Perimenopause: Symptoms, Stages and When to See Your GP

Perimenopause is the transitional stage leading up to menopause, and for many women it is the most symptomatic and confusing part of the entire journey. It can begin several years before your periods stop altogether, sometimes in your early forties or even your late thirties. Despite how common it is, many women reach this stage without understanding what is happening, or why they feel so different.

What perimenopause actually means

Menopause itself is defined as the point when you have not had a period for 12 consecutive months. Perimenopause is everything that comes before that: the months or years during which your ovaries gradually produce less oestrogen and progesterone, and your menstrual cycle becomes increasingly unpredictable. Some women breeze through it; others find it profoundly disruptive.

The average age of menopause in the UK is 51, but perimenopause can start 4 to 10 years earlier. That means a woman in her early forties, or even her late thirties, may be experiencing hormonal changes that she does not recognise as part of this transition.

The stages of the perimenopause transition

Perimenopause is not a single event. It unfolds in broad stages, though the boundaries between them are not always clear cut:

• Early perimenopause: cycles remain relatively regular, but you may notice subtle changes. Periods might be a day or two shorter or longer, PMS may intensify, and sleep may become less reliable. Hormonal blood tests at this stage can look normal, which is why symptoms are often dismissed.
• Mid perimenopause: cycle length starts to vary noticeably. You may skip periods or have them closer together. Symptoms such as hot flushes, night sweats, mood changes and brain fog become more apparent. Oestrogen levels can fluctuate dramatically, sometimes spiking before dropping.
• Late perimenopause: periods become increasingly infrequent, with gaps of 60 days or more between cycles. Symptoms may be at their most intense during this phase. Once you have gone 12 months without a period, you have reached menopause.

It is worth noting that the transition is rarely linear. You may have several months of intense symptoms followed by a stretch of feeling entirely normal, only for symptoms to return. This unpredictability is itself one of the most challenging aspects.

Common perimenopause symptoms

Perimenopause symptoms extend well beyond hot flushes. They can affect almost every system in the body, and many women do not realise their symptoms are hormonally driven:

• Irregular periods: shorter, longer, heavier, lighter or skipped altogether
• Hot flushes and night sweats
• Sleep disturbance and fatigue
• Mood changes: anxiety, irritability, low mood, tearfulness
• Brain fog, difficulty concentrating and memory lapses
• Joint and muscle aches
• Headaches and migraines, often worsening premenstrually
• Reduced libido and vaginal dryness
• Heart palpitations
• Weight changes, particularly around the middle
• Urinary symptoms such as increased frequency or urgency
• Skin and hair changes, including dryness and thinning

One of the most common things I hear in consultations is, "I had no idea these symptoms were connected to my hormones." Anxiety, palpitations and joint pain are frequently investigated in isolation, leading to frustration and delayed recognition.

How perimenopause is different from menopause

While menopause marks the end of ovarian function, perimenopause is a state of flux. Oestrogen levels can swing unpredictably from high to low, sometimes within the same cycle. This hormonal volatility explains why symptoms can feel so erratic: you may have a dreadful week followed by a perfectly normal one. By contrast, once you reach menopause, oestrogen settles at a consistently low level and symptoms often become more stable (though they may persist for years).

Why standard blood tests can be misleading

Many women are told their blood tests are "normal" and therefore they cannot be in perimenopause. This is a common source of confusion. FSH (follicle-stimulating hormone) levels fluctuate widely during perimenopause, and a single reading can fall within the normal range even when the transition is well under way. NICE guidance is clear: in women over 45 with typical symptoms, perimenopause is a clinical diagnosis and routine hormone testing is not required. For women under 45, blood tests may be more helpful, but they should be interpreted alongside symptoms, not used to rule the diagnosis out.

When to see your GP

You do not need to wait until symptoms are severe to seek help. Consider seeing your GP or a menopause specialist if:

• Your symptoms are affecting your quality of life, sleep, relationships or work
• You are experiencing heavy or very irregular bleeding that feels abnormal for you
• You are under 45 and suspect you may be in perimenopause, or under 40 and experiencing symptoms (this may indicate premature ovarian insufficiency, which needs specific investigation)
• You have tried managing symptoms on your own without improvement
• You want to discuss whether HRT or other treatments might be appropriate for you
• You are experiencing low mood, anxiety or cognitive changes that you suspect are hormonal

There is no minimum threshold of suffering required before you "deserve" help. If you are noticing changes and want to understand them, that is reason enough.

What can be done

Perimenopause is highly treatable. Options include HRT, which remains the most effective treatment for vasomotor symptoms and can also help with mood, sleep and joint pain. For women who cannot or prefer not to use HRT, there are effective non-hormonal alternatives. Lifestyle measures, including regular exercise, balanced nutrition, stress management and good sleep hygiene, play an important supporting role alongside any medical treatment.

The most important step is recognition. Once you understand that what you are experiencing has a hormonal basis, the path to feeling better becomes much clearer.

“Perimenopause is not something you simply have to endure. Understanding what is happening is the first step, and there is effective help available at every stage.”

Dr Itunu Johnson

Clinical content flagged for Dr Itunu Johnson's review before publication.

If you would like to discuss your perimenopause symptoms, or want a personalised plan, you can book a consultation or read more about my menopause care.