5 Early Signs of Perimenopause Most Women Miss

The five most commonly missed early signs of perimenopause are irregular periods, disrupted sleep, brain fog or memory lapses, mood changes, and fatigue that doesn't improve with rest. Because these symptoms often start gradually in your late 30s or 40s, long before hot flushes appear, many women put them down to stress, ageing, or simply "a busy life" rather than perimenopause.

Do any of these early signs of perimenopause sound familiar?

1. Irregular periods

This is usually the first sign, and often the one that gets recognised, eventually. Cycles might become shorter, longer, heavier, lighter, or just less predictable than they used to be. It's easy to dismiss a few "off" months, but a genuine shift in your usual pattern is one of the clearest early markers of hormonal change. We recommend using an app such as Flo to track your periods.

2. Disrupted sleep

Waking at 3am and lying there wide awake, even when you're exhausted, is a hallmark early sign. This isn't just "getting older" or a bad week. Falling oestrogen and progesterone directly affect sleep patterns, so this happens before other symptoms do. We cover practical strategies for this in our post on improving sleep during perimenopause.

3. Brain fog and memory lapses

Walking into a room and forgetting why, losing a word mid-sentence, struggling to concentrate at work, or forgetting famous peoples names! This is one of the most common and most under-recognised perimenopause symptoms. A recent UK survey of women attending a menopause clinic found memory problems and difficulty concentrating were reported by the vast majority of participants, alongside fatigue, yet these cognitive symptoms rarely get discussed as early perimenopause signs.

4. Mood changes and anxiety

Irritability, low mood, or anxiety that feels different from your usual is worth paying attention to. Many women are offered antidepressants for this before discussing the possibility of perimenopause, when the root cause is often hormonal rather than purely psychological.

5. Fatigue that doesn't lift with rest

Ordinary tiredness improves with a good night's sleep or a quieter weekend. Perimenopausal fatigue (sometimes referred to as crashing fatigue) often doesn't, it's a heavier, more persistent exhaustion that's there even after rest, frequently tied to blood sugar swings and disrupted sleep working together.

How is perimenopause actually diagnosed?

There is no single test. Current NICE guidance (NG23) states that in otherwise healthy women aged 45 or over, perimenopause can be identified based on symptoms alone, specifically the recent onset of vasomotor symptoms (like hot flushes) alongside changes in your menstrual cycle, without needing laboratory tests such as an FSH blood test. This is exactly why the signs above matter so much: recognising the pattern yourself is often the first real step, before any clinical test would confirm it.

Symptoms like brain fog, mood changes, and fatigue can start well before hot flushes do, which is a big part of why they're so often missed or misattributed to something else entirely.

What should you do if you recognise these early signs of perimenopause?

You don't need to wait for symptoms to become severe, or for a doctor to confirm perimenopause with a test that may not even be appropriate, before taking action. A good starting point is simply naming what's happening and understanding how nutrition, blood sugar balance, and lifestyle changes can genuinely help manage these early symptoms, alongside speaking to your GP about the full range of options available to you, including HRT if it's right for you.

If fatigue is one of your main symptoms, or you're weighing up whether HRT, nutrition, or both is the right next step, these posts go into more detail. And if you're starting to look for support and aren't sure what to look for in a practitioner, our guide on how to choose a nutritionist for perimenopause and menopause covers exactly that.

Want a simple starting point? Download our free guide, The 5-Day Energy Reset, or book a free, no-obligation Health and Energy Review to talk through what's going on. Book your free Health and Energy Review →