Menopause and Perimenopause: What Blood Tests Can Tell You

The menopause transition can bring a bewildering mix of symptoms, and many women want to know whether a blood test can confirm what's happening. The honest answer is: sometimes. Hormone tests have a real role, but also clear limits. Understanding both helps you know when testing is worth it — and when your symptoms and age tell the story on their own.

Perimenopause vs menopause

Perimenopause is the years-long run-up when hormones fluctuate and periods become irregular. Menopause is a single point — 12 months after your last period — after which you're described as postmenopausal. Most symptoms people call "the menopause" actually happen during perimenopause, while hormones are swinging up and down.

Common symptoms

• Irregular, heavier or lighter periods
• Hot flushes and night sweats
• Sleep problems and fatigue
• Mood changes, anxiety or low mood, and brain fog
• Vaginal dryness and reduced libido
• Joint aches and skin changes

What blood tests can — and can't — show

The main hormones measured are FSH (which tends to rise as the ovaries wind down) and oestradiol (which tends to fall). The catch is that in perimenopause these levels fluctuate day to day, so a single result can look "normal" even when you're clearly perimenopausal. That's why UK guidance says that for women over 45 with typical symptoms, diagnosis is usually clinical — based on your symptoms and cycle, not a blood test.

When testing is more useful

Hormone testing genuinely helps in specific situations:

• You're under 45 with menopausal symptoms (to look for early menopause).
• You're under 40, where premature ovarian insufficiency is a possibility and usually needs repeated FSH testing.
• The picture is unclear, or symptoms could have another cause.
• You've had a hysterectomy and can't use periods as a guide.

Because thyroid problems mimic menopause so closely, thyroid function is often checked at the same time to avoid missing a treatable overlap.

How results guide treatment

Test results are a starting point for a conversation, not a prescription in themselves. If your symptoms are affecting your quality of life, your doctor can discuss options including hormone replacement therapy (HRT), weighing the benefits and any personal risks with you. Many women are offered HRT based on symptoms alone, with blood tests used mainly in the less clear-cut cases above.

When to get checked

If menopausal symptoms are disrupting your sleep, mood or daily life — especially if you're under 45, or unsure whether your symptoms are hormonal — it's worth testing and speaking to a clinician. You don't have to simply put up with it.

Written by Dr Ibrar Ahmed — MBChB MRCP MRCGP PhD PG Dip (Cardiology)
Specialist interest: Cardiovascular Medicine · OneMedicine, CQC-registered clinic