Can a blood test tell you if you’re perimenopausal?

What perimenopause is

Menopause is the point when periods have stopped for good. The NHS says it usually happens between the ages of 45 and 55, and it can happen earlier.

Perimenopause is the time leading up to it. Your hormones start to change and you may notice symptoms, but you're still having periods, even if they're becoming irregular. For many women this stage lasts several years.

The NHS lists a wide range of symptoms, including:

• changes to your periods
• hot flushes and night sweats
• difficulty sleeping
• mood swings, low mood or anxiety
• brain fog and problems with memory or concentration
• joint and muscle aches
• headaches and palpitations
• lower sex drive and vaginal dryness

Many of these can also have other causes, which is part of why perimenopause can be hard to recognise.

What your hormones do across the transition

The best picture we have comes from SWAN, a large US study that followed women through the menopause transition and measured their hormones over many years.

On average, it found:

• FSH (follicle stimulating hormone) began to rise about six years before the final period, sped up about two years before, and levelled off about two years after.
• Oestradiol (the main form of oestrogen) did not change much until about two years before the final period. Then it fell, and settled about two years after.

Average pattern across the menopause transition, from the SWAN study. Individual patterns vary, and hormone levels can swing month to month.

FSH is a message from your brain to your ovaries. As the ovaries respond less, the brain sends a louder message, so FSH goes up. In other words, your brain notices the change before you do.

These are averages across many women. Your own pattern may look different.

Why one result can't settle it

In perimenopause, hormone levels don't fall in a straight line. They swing. FSH can be high one month and back down the next. Oestradiol can rise and fall, sometimes higher than before. That's why symptoms can come and go.

A single blood test is a snapshot of one day. On another day, the same woman could get a quite different result.

Other things change the numbers too:

• The day of your cycle. Oestradiol, FSH and LH all move through the month, so the same woman can have very different results a week apart.
• Hormonal contraception and HRT. The pill and some other contraceptives suppress your body's own hormones. Some HRT contains oestradiol and will raise the reading. If you use either, a hormone test won't show your natural levels.
• Pregnancy and breastfeeding.

GPs on an NHS England podcast for World Menopause Day said hormone testing in perimenopause is often unnecessary, and that NICE advises against routine oestradiol testing. In UK practice, perimenopause in women over 45 is usually recognised from symptoms rather than blood tests. If you're over 45 and have symptoms, your GP is the right first step.

So what can a hormone blood test show?

Used for the right reasons, a hormone test gives you useful information.

Your levels on the day. You see where your hormones were when you took the sample, with each result shown against the reference range used by the lab.

A baseline for the future. One result is a snapshot. Two start to tell a story. Testing in your late 30s or early 40s gives you something to compare against as things change.

Other markers whose symptoms overlap. Tiredness, low mood, weight change, poor concentration and heavier or irregular periods appear on the NHS symptom list for an underactive thyroid as well as for perimenopause. Raised prolactin, a hormone made by the pituitary gland, can make periods irregular or stop them. Seeing thyroid and prolactin alongside your female hormones gives a fuller picture.

GPs on the same NHS England podcast said tests for anaemia and thyroid remain relevant when symptoms suggest them. Those markers are in Claryty Energy and Claryty Complete.

What's in Claryty Hormones

Claryty Hormones looks at 11 markers from a home finger-prick kit:

• Oestradiol: your main oestrogen. It has a hand in your bones, heart, skin and brain, not just your cycle.
• FSH and LH: messages from your brain to your ovaries.
• Prolactin: best known as the milk hormone. When it's raised for other reasons, it can affect your periods.
• Testosterone, free testosterone, SHBG and free androgen index: women make testosterone too. SHBG is a protein that holds on to it, a bit like a sponge, so these markers together show how much is available to use.
• TSH, free T4 and free T3: your thyroid. TSH is the message your brain sends to your thyroid; higher TSH points to a thyroid working less.

Every result comes with the reference range used, what the marker measures, why it's tested and what can influence it, in plain English. Samples are analysed by our UK laboratory partner, and results typically arrive 1–2 working days after your sample reaches the lab.

Claryty Hormones is not a menopause test or a fertility test, and it doesn't measure progesterone or AMH.

When to speak to your GP

Speak to your GP if:

• you have symptoms that are affecting your life, whatever your age
• your periods have become very heavy, or you bleed between periods or after sex
• you're under 45 and think you may be going through perimenopause or menopause
• anything feels new, worrying or different from your normal

Your GP can talk through your symptoms and the options, including treatments. Claryty provides information, not diagnosis, and our results are designed to help you have a better-informed conversation, not to replace one.