Why Hormone Blood Tests might not tell the whole story!

Here’s Why Hormone Blood Tests Aren’t Always Accurate in Perimenopause & Menopause

And what UK guidance actually says… so you can advocate for yourself with confidence.

If you’ve ever been told, “Your blood tests are normal, so it’s not menopause,” you’re not alone.

In fact, this is one of the most common (and most frustrating) experiences women share with me.

Here’s the truth:

Hormone blood tests can be helpful, but during perimenopause they are often completely unreliable — and even the NHS and UK menopause bodies know this.

Let’s break it down in a way that makes sense, removes the confusion, and gives you the knowledge to walk into your next appointment feeling M~Powered.

1. Hormones in Perimenopause Are Wildly Fluctuating — Not Steady

Your sex hormones aren’t steady little soldiers marching neatly across the month.

Even in a normal menstrual cycle, oestrogen and progesterone rise and fall dramatically depending on the phase.

But in perimenopause?

Those swings become erratic, unpredictable and often extreme.

Research has shown that:

   •   Hormone levels in perimenopause can vary massively from day to day and cycle to cycle.

   •   Around 90% of perimenopausal women show big changes in oestrogen across cycles, and progesterone may be high one month and absent the next.

Which means…

A single blood test is just one snapshot of your hormones at one moment — and it can’t reflect the chaos happening behind the scenes.

You can have:

   •   “Normal” oestrogen on the day of your test

   •   But still experience hot flushes, anxiety, night sweats, mood swings, brain fog, low libido, joint pain and irregular periods

Because symptoms are often driven by fluctuations, not the reading taken on Tuesday at 9.12am.

2. What the UK Actually Says About Hormone Testing

This bit is important…

Because many women don’t realise the UK guidance is already on their side.

✔ NICE Guidance (NG23 – the UK menopause guideline)

For women aged 45 and over, NICE says:

Do NOT use blood tests to diagnose perimenopause or menopause.

Diagnosis should be based on symptoms.

They also say:

   •   Do not use oestrogen levels

   •   Do not use AMH

   •   Do not use inhibin tests

   •   Do not rely on FSH in women using hormonal contraception

They are very clear:

If you are 45+ and have symptoms, you do not need a blood test for a diagnosis.

✔ British Menopause Society (BMS)

The BMS agrees, stating that hormone testing is not required for diagnosing peri/menopause in women 45+ unless there is diagnostic uncertainty.

3. Why Blood Tests Can Mislead Women

There are several reasons your test might look “fine” even when you feel anything but fine.

a) Cycle timing matters — a lot

Oestrogen and progesterone look totally different:

   •   Before ovulation

   •   During ovulation

   •   After ovulation

But in perimenopause your cycle may be:

   •   Longer

   •   Shorter

   •   Irregular

   •   Anovulatory

   •   Double ovulatory

…so timing a test becomes almost impossible.

b) Hormones change hourly

Estradiol in particular has been shown to fluctuate within hours.

This is why symptoms can hit suddenly even when tests look “normal.”

c) Medications and HRT affect the numbers

This includes:

   •   The combined pill (suppresses FSH, LH)

   •   Progestogen-only contraception

   •   Mirena and other IUS

   •   HRT itself

So your numbers may not truly reflect your natural hormone state.

d) Different labs use different reference ranges

One lab’s “normal” can be another lab’s “low.”

This is especially true for estradiol.

4. The UK Numbers: Why This Matters

This is not a small issue.

In the UK:

   •   There are 7.2 million women aged 45–60

   •   Around 4 million women aged 45–55 are currently in the workforce

   •   Most women experience menopause between 45–55, but perimenopause often starts up to 10 years earlier

So millions of women are being told their symptoms “aren’t menopause” because of a single blood test…

even though UK experts say blood tests are often unnecessary and misleading.

5. So Should We Scrap Hormone Blood Tests?

Not at all — they have their place.

They’re useful when:

✔ A woman is under 40 and POI is suspected

✔ A woman is 40–45 with symptoms and irregular cycles

✔ A doctor needs to rule out other issues (thyroid, pituitary, prolactin, etc.)

But for most women over 45 with classic symptoms…

A blood test is not needed and often doesn’t tell the real story.

Your symptoms do.

This is exactly what NICE and the BMS state — and what many GP consultations still miss.

6. What You CAN Do as an Informed Woman

Here’s how to take your power back:

Track your symptoms

Your story is often more accurate than a lab report.

Know your rights

If you’re 45+, symptomatic, and being denied help because of “normal” bloods — that is not in line with UK guidance.

Ask how the test changes your care

If the answer is “to see if it’s menopause,”

that’s not a clinically supported use of testing for 45+.

Advocate gently but firmly

You are NOT being dramatic.

You are NOT imagining it.

Your symptoms matter, and the guidance supports you.

Final Word: Trust Your Body — Not Just Your Blood Test

Perimenopause and menopause are clinical diagnoses.

They are based on how you feel, how your cycle behaves, and how your symptoms affect your life.

You know your body better than any lab sheet.

And if you need support with symptoms, guidance or a personalised peri/menopause plan, my Meno Method and 1:1 mentoring are here to help you feel like YOU again — energised, empowered and back in control.

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