Why Blood Tests Are Often Normal in Perimenopause

When you have finally asked for help, when you have explained how bad it has been, when you have hoped someone will say "yes, I see what you mean," being told everything is normal can feel like the door shutting in your face.

It makes you question yourself. Maybe you are making too much of it. Maybe other women cope better. Maybe you should just get on with it.

You are not making too much of it. The test is not designed to pick up what you are experiencing. That is not the same as nothing being there.

Rachel

Rachel came to see me after six months of feeling worse and worse. She had already seen two other GPs at a different practice.

Bad sleep. Anxiety she had never had before. Brain fog so thick that she had started writing things down because she could not trust her memory.

Both previous appointments had ended the same way. "We'll do some bloods to check everything's okay."

The bloods came back normal. Both times.

"The second doctor said it was probably stress," she told me. "She suggested I try yoga."

By the time Rachel sat in my room, she was angry, and underneath the anger she was frightened. Frightened that nobody was going to take her seriously. Frightened that she was going to keep feeling this way forever. Frightened, most of all, that she was making it up.

She was not making it up.

The problem with testing hormones in perimenopause

Think of trying to understand British weather by stepping outside once, for five minutes, on a random Tuesday in April.

You might get bright sunshine. You might get heavy rain. You might get that odd bit where it is doing both at once.

Would that five-minute snapshot tell you what the weather has been like all month? Of course not.

That is what a blood test does in perimenopause. It captures one moment.

But perimenopause is not a one-moment situation. It is a moving one. Your oestrogen and progesterone do not drop in a tidy, straight line. They spike and crash. They go up, down, up, down, sometimes within the same week.

If your blood is taken on a "high" day, the result looks normal. Three days later you might feel terrible, but the test does not know that. It only knows what was in your blood on the morning you happened to give the sample.

The test was not lying about that moment. It was just looking at one moment, in a condition that does not stay still.

What about the FSH test?

FSH stands for follicle-stimulating hormone. It is the test most often used to "check for menopause."

When your ovaries slow down their oestrogen production, your brain releases more FSH, trying to get them going again. High FSH suggests you are getting close to menopause. Normal FSH suggests you are probably not there yet.

That sounds simple. Here is why it is not.

FSH also goes up and down in perimenopause. You can have a high reading one month and a normal one the next. One test does not tell you much.

And here is the bigger point. You can have a completely normal FSH and still be firmly in perimenopause, with every symptom there is.

The FSH test was not designed to diagnose perimenopause. It was designed to confirm menopause once your FSH stays high all the time. Using it to diagnose perimenopause is a bit like using a pregnancy test to confirm you are in labour. Wrong tool. Wrong time.

This is why NICE guidance says that for women over 45 with typical symptoms, an FSH test is not needed at all. The diagnosis is made on the symptoms. The test, when it is done, is often done despite the guidance, not because of it.

What about private hormone panels?

I want to be direct with you, because I do not want you to spend money you do not need to spend.

Some women, after a normal NHS result, go private. Saliva tests. Urine tests. Detailed blood panels checking everything you can think of. They are hoping for answers. They are hoping that paying for more numbers will explain how they feel.

Most of these tests do not add useful information for diagnosing perimenopause. They are still snapshots. They still go up and down. And in most cases, they will not change what a sensible doctor would recommend doing anyway.

You are not getting better care by paying for more numbers on a page.

Save the money. Spend it on something that actually helps. Better sleep. A good therapist. Movement that feels good. Or, honestly, a decent night out with a friend who understands.

So how do we actually diagnose perimenopause?

If blood tests are unreliable, how does anyone work out whether someone is in perimenopause?

By using what actually works.

Your age. If you are in your late thirties or your forties, perimenopause is possible.

Your symptoms. What has changed? When did it start? How is it affecting your life?

Your cycle. Is it different from your usual pattern? Heavier, lighter, longer, shorter, skipping months?

That is the diagnosis. Perimenopause is diagnosed by listening to you and putting the pieces together. Not by staring at a blood test result.

When blood tests do matter

Blood tests are not useless. They have a job. It is just not the one many women have been told it is.

We use them to check for other things that can cause similar symptoms. Thyroid problems. Anaemia. Vitamin deficiencies. Autoimmune conditions. Diabetes.

We are not doing them to prove perimenopause. We are doing them to make sure nothing else is going on that needs different treatment.

That is a big difference, and it is worth knowing as you go into your next appointment.

What to do if you are stuck in normal-test limbo

Go back. Book another appointment. If your surgery has a GP with an interest in women's health or perimenopause, ask reception whether you can see that GP specifically.

When you are there, say it clearly. "I know my blood tests are normal. My symptoms are affecting my life. I would like to talk about perimenopause."

Describe the impact, not just the symptoms. "I am not sleeping, which means I am struggling at work and short with my children",  lands differently than "I am tired." The picture matters more than the list.

Ask about treatment options. Even without a blood test that "proves" anything, there are things that can help. Some are lifestyle. Some are medical. Sometimes both.

And if the appointment does not go well, if you leave feeling dismissed again, you can ask for a second opinion. You are entitled to one. Not every GP is up to date on perimenopause. That is not your fault.

What I want you to take from this

Your symptoms matter more than a number on a page.

If you are not sleeping, if your mood has changed, if you are struggling in ways you have not before, if your periods are different, that information is the diagnosis. A blood test that says "normal" does not cancel out what you are living.

It just means the test did not catch it.

The next post on this blog will be about what to take with you when you go back to your GP. Not just the questions to ask. The way to ask them, so that the appointment uses your ten minutes well.

Patient details have been changed. The clinical pattern is real

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Medical Disclaimer: All content is for educational purposes and does not constitute medical advice or a doctor-patient relationship; always consult your own doctor for clinical concerns