Perimenopause in Your Late 30s: No, You’re Not Too Young

Perimenopause symptoms in your late 30s are real — and they’re often missed. Here’s what the early signs can look like, when to seek support, and what may help.

You’re 37.

Maybe 38.

And something feels… off.

Your periods are suddenly doing things they’ve never done before.

You’re waking at 3am, wide awake, with absolutely no idea why.

Your mood feels less predictable.

You’re struggling to find words you normally use without thinking.

And perhaps you’ve caught yourself wondering:

“Is this just stress… or is something else going on?”

Because you’re in your late 30s, you might assume perimenopause couldn’t possibly be part of the picture.

But here’s the thing:

Menopause usually happens between 45 and 55 — but the hormonal transition leading up to it can begin earlier.

And if you’re experiencing significant changes before 40, it’s particularly important not to simply brush them off. NICE recommends assessment for possible premature ovarian insufficiency (POI) in people under 40 with menopause-associated symptoms.

So no, asking questions about your hormones in your late 30s isn’t being dramatic.

It’s paying attention.

The signs nobody tells you to look for

Most of us grow up thinking menopause is a 50s problem.

We picture hot flushes.

Maybe night sweats.

Maybe a few jokes about forgetting where we put our keys.

But perimenopause can be much less obvious — and symptoms can vary hugely from one person to another.

One of the first things to notice can be a change in your menstrual cycle.

Your periods might become:

• More frequent

• Less frequent

• Heavier

• Lighter

• Longer

• Shorter

• Less predictable

The NHS notes that changes to your periods are often one of the first signs of perimenopause.

And then there are the symptoms that are much easier to blame on… well, everything else.

Sleep that suddenly doesn't behave

You fall asleep fine.

Then — hello, 3am.

Wide awake.

Brain switched ON.

And suddenly you're thinking about an email you sent three weeks ago.

Sleep problems are a recognised symptom of perimenopause and menopause, alongside symptoms such as low mood, anxiety and memory or concentration difficulties.

Your mood feels different

Maybe you're more irritable.

Maybe you're more emotional.

Maybe your resilience just isn't what it used to be.

And no, that doesn't mean you're simply being “hormonal”.

Hormonal changes can be associated with changes in mood, and the NHS lists low mood and anxiety among menopause and perimenopause symptoms.

Brain fog

You know the word.

You've used it approximately 4,000 times.

Except suddenly… you can't remember it.

You walk into a room and forget why.

You start a sentence and lose the plot halfway through.

You wonder whether you're just exhausted.

Memory and concentration problems can occur during perimenopause and menopause too.

And that's where things get interesting.

Because none of these symptoms necessarily screams “hormones” on its own.

But when several changes start appearing together — particularly alongside changes to your cycle — it's worth stepping back and looking at the bigger picture.

“But my blood tests were normal…”

This is one of the trickier parts of the conversation.

Hormones fluctuate. So a single blood test isn't necessarily a complete picture of what's happening — and the way menopause is assessed depends partly on your age and symptoms.

For people aged 45 and over with typical symptoms, NICE recommends identifying perimenopause and menopause based on symptoms rather than routine hormone blood tests.

But that's different if you're younger.

NICE says FSH testing can be considered when menopause is suspected in people aged 40–45, and recommends FSH testing on two occasions, 4–6 weeks apart, when diagnosing premature ovarian insufficiency in people under 40.

So if you're 37, 38 or 39 and experiencing significant changes, don't assume you're “too young” simply because you're not 45 yet.

Your symptoms deserve to be properly explored.

And importantly, other possible causes of changes to your periods or symptoms should be considered too.

So, what can actually help?

This is where I always encourage women to step away from the idea that there's one magic fix.

There isn't.

And “natural” doesn't automatically mean “safe” or “effective” either.

A more useful starting point is understanding what is actually happening for you.

That might mean looking at:

Your cycle:
What's changed? When did it change? Are your periods becoming heavier, closer together or less predictable?

Your sleep:
Are you struggling to fall asleep, waking during the night, or waking earlier than usual?

Your mood:
Are anxiety, irritability or low mood showing up differently?

Your cognitive symptoms:
Are concentration and memory becoming noticeably harder?

Your wider health picture:
What else is happening in your life, health, nutrition, stress levels and medications?

From there, you can make much more informed decisions about the support that's appropriate for you.

For some women, this may include lifestyle changes, nutritional support or psychological approaches. For others, medical treatment may be appropriate.

And if you're considering herbal medicine, it's worth getting personalised advice rather than simply grabbing a “menopause supplement” off the shelf. Evidence for many herbal products marketed for menopause symptoms is limited or inconsistent, and some herbs can interact with medicines or have side effects.

The goal isn't to throw everything at your hormones.

It's to understand your individual picture and choose support based on that.

You're not imagining it. But don't diagnose yourself from Instagram, either.

Here's the bit I really want you to take away:

Feeling different doesn't automatically mean you're in perimenopause.

But being in your late 30s doesn't automatically rule it out, either.

If your cycle has changed and you're experiencing new symptoms — particularly if you're under 40 — it's worth speaking to a GP or appropriately qualified healthcare professional rather than writing it off as stress, getting older, or “just one of those things”.

And if your periods have become significantly heavier, especially alongside other changes, that's worth discussing with your GP too.

Because your body isn't being difficult.

It's giving you information.

The trick is learning how to listen to it.

Wondering where to start?

If you're sitting there thinking:

“Okay… this sounds suspiciously familiar.”

Start by getting a clearer picture of your symptoms rather than trying to Google every single one at 2am.

Take the 2-minute Hormone Health Quiz to explore what may be going on and what your next steps could look like.

Take the 2-minute Hormone Health Quiz →

References

1. NICE. Menopause: identification and management (NG23). Updated April 2026. Guidance on identifying perimenopause and menopause, including assessment of premature ovarian insufficiency.

2. NHS. What are menopause and perimenopause? Information on the menopause transition, typical age range and common symptoms.

3. NHS. Symptoms of menopause and perimenopause. Information on menstrual changes, sleep, mood, memory and other symptoms.

4. NHS. Early or premature menopause. Information on menopause before 45 and premature menopause before 40.

5. British Menopause Society. Premature ovarian insufficiency. Guidance on diagnosis and management of POI.

6. National Center for Complementary and Integrative Health (NCCIH). Menopausal Symptoms: In Depth. Evidence and safety considerations for herbs, supplements and complementary approaches.

Medical note: This article is for general education and isn't a substitute for individual medical advice or diagnosis. If you're experiencing new, persistent or concerning symptoms, speak with your GP or another appropriately qualified healthcare professional.

Marie Mulcahy is a NIMH-registered Medical Herbalist supporting women through PCOS, perimenopause, PMDD and endometriosis, with clinics in Clitheroe and Darwen and UK-wide online consultations.

Frequently Asked Questions About Perimenopause in Your Late 30s

Can you start perimenopause in your late 30s?

The menopause transition can begin before the typical age of menopause, although menopause most commonly occurs between 45 and 55.

If you're experiencing menopause-associated symptoms before the age of 40, it's important to speak with your GP or another appropriately qualified healthcare professional. This is because premature ovarian insufficiency (POI) is one possible cause and may need specific assessment.

What are the first signs of perimenopause?

Changes to your menstrual cycle are often one of the first signs. Your periods may become heavier, lighter, longer, shorter, more frequent or less predictable.

Other symptoms can include sleep difficulties, mood changes, anxiety, memory or concentration problems, hot flushes and other physical symptoms.

The experience can look different from woman to woman, which is one reason perimenopause can be easy to miss.

Can perimenopause cause brain fog?

Yes. Memory and concentration difficulties are recognised symptoms associated with perimenopause and menopause.

You might notice that you're struggling to find words, losing your train of thought or finding it harder to concentrate on tasks that previously felt effortless.

That doesn't automatically mean perimenopause is the cause, though. If you're experiencing persistent or concerning changes, it's worth discussing them with a healthcare professional.

Can perimenopause affect sleep?

Yes. Sleep difficulties are common during perimenopause and menopause.

You might struggle to fall asleep, wake during the night or find yourself regularly waking earlier than usual.

If you're waking at 3am and suddenly finding your brain has decided it's time to conduct a full business meeting about everything you've ever done… you're definitely not alone.

But persistent sleep problems are worth discussing, particularly if they're affecting your mood, work or everyday life.

Can you have perimenopause symptoms with normal blood tests?

It depends on your age, symptoms and what is being investigated.

Hormone levels naturally fluctuate, so a single hormone measurement doesn't necessarily provide a complete picture.

NICE recommends different approaches depending on age. For people aged 45 and over with typical symptoms, perimenopause and menopause are generally identified based on symptoms rather than routine hormone blood tests.

If menopause is suspected before the age of 40, however, premature ovarian insufficiency (POI) needs to be considered and appropriate assessment may be recommended.

What should I do if I think I'm experiencing perimenopause in my late 30s?

Start by paying attention to your pattern.

Keep track of changes to your menstrual cycle alongside symptoms such as sleep disruption, mood changes, brain fog or other physical changes.

Then speak with your GP or another appropriately qualified healthcare professional about what you're experiencing.

If you're under 40 and experiencing symptoms associated with menopause, don't simply assume you're “too young” or that it's all down to stress. Your symptoms deserve to be properly explored.

Can herbal medicine help with perimenopause symptoms?

Some women explore herbal medicine and other complementary approaches to support their wellbeing during perimenopause.

However, evidence for many herbal products marketed for menopause symptoms is limited or inconsistent, and some herbs can interact with medicines or cause side effects.

If you're considering herbal medicine, personalised advice from an appropriately qualified practitioner is preferable to choosing a menopause supplement at random.

The right approach depends on your individual symptoms, health history and any medicines you're taking.

When should I speak to my GP about perimenopause symptoms?

Speak with your GP if you're experiencing new or persistent symptoms that are affecting your everyday life, particularly if your periods have changed significantly.

If you're under 40 and experiencing menopause-associated symptoms, it's particularly important to seek appropriate assessment rather than assuming you're simply experiencing typical perimenopause.

And if you have very heavy bleeding, bleeding between periods or other symptoms that concern you, don't just put it down to hormones. Get it checked.

Still wondering where to start?

If you're sitting there thinking, “Okay… this sounds suspiciously familiar,” you're not alone.

Rather than trying to Google every symptom at 2am, start by getting a clearer picture of what's actually going on.

Take the 2-minute Hormone Health Quiz →

Medical disclaimer: This article is for general educational purposes only and isn't intended to diagnose, treat or replace individual medical advice. If you're experiencing new, persistent or concerning symptoms, speak with your GP or another appropriately qualified healthcare professional.