5 Unexpected Signs of Perimenopause (That Many Women Don’t Recognise)
Perimenopause is often associated with hot flushes and irregular periods, but many of the earliest signs are far less obvious.
Because hormone fluctuations affect the brain, metabolism, sleep, and nervous system, symptoms can appear in ways that are easily mistaken for stress, ageing, or lifestyle factors.
Here are 5 unexpected signs of perimenopause that are commonly missed.
1. Waking at 3–4am for no clear reason
One of the most common early signs is disrupted sleep—particularly waking in the early hours and struggling to fall back asleep.
This is often driven by:
fluctuating oestrogen affecting sleep regulation
changes in progesterone (a calming hormone)
increased cortisol sensitivity overnight
Many women describe feeling “tired but wired” at this time.
2. Increased anxiety or physical “stress sensitivity”
You may notice:
feeling more easily overwhelmed
sudden waves of anxiety
heart racing or palpitations
feeling “on edge” without a clear trigger
Hormonal fluctuations affect neurotransmitters such as serotonin and GABA, which regulate calmness and stress response. This can make the nervous system more reactive than before.
3. Brain fog and reduced mental clarity
This is one of the most under-recognised symptoms.
Women often describe:
difficulty concentrating
forgetting words or tasks
slower thinking
feeling mentally “less sharp”
Oestrogen plays a role in cognitive function, so fluctuations can affect focus and memory even in high-functioning women.
4. Sudden changes in body composition
Without major changes in diet or exercise, you may notice:
weight gain around the abdomen
loss of muscle tone
changes in how your body stores fat
This is related to hormonal shifts affecting metabolism, insulin sensitivity, and fat distribution.
It is not simply “ageing” or lack of discipline.
5. Changes in emotional resilience
Many women report:
crying more easily
feeling less emotionally “resilient”
increased irritability
stronger emotional reactions to small triggers
This reflects hormonal influence on mood regulation pathways in the brain, not personality change.
Why these signs are often missed
Perimenopause is frequently under-recognised because:
periods may still be regular in early stages
symptoms fluctuate
blood tests may appear normal
symptoms overlap with stress, burnout, or anxiety
As a result, many women are told it is “just stress” or lifestyle-related, delaying diagnosis and support.
When perimenopause may be the cause
You may be experiencing perimenopause if:
you are typically in your 40s or early 50s
symptoms are new or changing
there is a combination of sleep, mood, and physical changes
symptoms come and go or vary in intensity
What can help
Support should always be individualised, but may include:
1. Clinical assessment
A symptom-based approach is often more useful than relying solely on blood tests.
2. Hormone replacement therapy (HRT)
For many women, HRT can improve:
sleep quality
mood stability
brain fog
energy levels
3. Lifestyle and metabolic support
strength training and movement
blood sugar stability
sleep hygiene
stress regulation
4. Excluding other conditions
It is important to rule out:
thyroid dysfunction
iron deficiency
vitamin deficiencies
mental health conditions where appropriate
The key message
Perimenopause does not always start with obvious reproductive symptoms.
For many women, it begins subtly—with changes in sleep, mood, cognition, and energy that are easy to dismiss or misattribute.
Recognising these early signs can make a significant difference to treatment, quality of life, and long-term health.
