Perimenopause or Nervous System Dysregulation? Why So Many Women in Their Late 30s Are Being Misdiagnosed

Anxiety, brain fog, poor sleep, mood swings in your late 30s? It might be perimenopause - or nervous system dysregulation - or both. Here's how to tell the difference.

You are thirty-seven. Or forty-one. Or somewhere in between.

You are not sleeping well. Your anxiety has ramped up in a way that feels qualitatively different from before - more physical, more sudden, less connected to anything you can point to. Your brain feels slower. Your moods swing in ways that surprise even you. Your digestion has become unpredictable. You are tired in a way that doesn't lift. And you feel, in some way you struggle to articulate, like you are not quite yourself anymore.

You go to your doctor. You describe your symptoms. And one of two things happens.

Either you are told it is probably perimenopause - here is some information about HRT, come back if things don't improve. Or you are told your hormones look fine for your age, it is probably stress, perhaps try mindfulness. Either way, you leave with the sense that something has been missed. Because the explanation you've been given doesn't quite account for everything you are experiencing. And the treatment, if you've been offered one, doesn't quite reach all of it.

Here is what I want to offer you in this post. Not a simple answer - because there isn't one. But a framework that most women in their late thirties and early forties are not being given, and that I believe would change everything about how they understand and address what is happening in their bodies.

The framework is this: perimenopause and nervous system dysregulation share almost identical symptoms. They interact with and amplify each other. And treating one without addressing the other is one of the most common reasons women in this age group find themselves stuck - partially better, but not well.

What Perimenopause Actually Is - and When It Starts

Let's begin with the basics, because perimenopause is significantly earlier and significantly more varied than most women are told.

Perimenopause is not menopause. It is the transition toward menopause - a period of hormonal fluctuation, rather than hormonal absence, that can begin as early as the mid-thirties and typically lasts anywhere from two to ten years. It ends twelve months after your last period. Everything before that point is perimenopause.

The menopausal transition is a major neurological transition state - the brain is exposed to drastically changing levels of ovarian hormones, similar to puberty but in reverse. And because estrogen and progesterone are not just reproductive hormones - they are neuroactive hormones that directly influence brain chemistry and nervous system function - the effects of their fluctuation are felt throughout the entire body, not only in the reproductive system.

Estrogen supports serotonin and dopamine, two key neurotransmitters that regulate mood, motivation, and calm. As estrogen levels fluctuate and eventually decline, the brain's access to these stabilising chemicals becomes less predictable. Progesterone has a naturally sedating effect through its action on GABA receptors - the same receptors that anti-anxiety medications work on. As progesterone drops, the nervous system's natural capacity to self-soothe decreases. And estrogen also helps regulate cortisol - your primary stress hormone. When estrogen drops, cortisol spikes more easily, keeping your nervous system on alert longer than it used to.

The five most common perimenopausal symptoms, according to a large 2024 study, are not hot flushes and night sweats. They are fatigue, memory problems, difficulty concentrating, irritability, and feeling tense or nervous. Hot flushes ranked eighteenth.

Read that again. The most common symptoms of perimenopause are the same symptoms that characterise nervous system dysregulation, chronic stress, and burnout.

This is where the diagnostic confusion begins. And it is why so many women are being partially treated - or not treated at all.

What Nervous System Dysregulation Looks Like at This Life Stage

Now let me describe nervous system dysregulation - specifically as it presents in high-functioning women in their late thirties and early forties.

Your nervous system has been under load. Years of it, in most cases. The career, the relationships, the caregiving, the mental load of managing a life that demands constant output. Many women in this age group are also at peak professional responsibility, peak domestic complexity, and frequently mid-way through processing things from earlier in their lives that never fully resolved - old relational patterns, old stress that was moved through rather than metabolised, old versions of themselves that kept going because stopping wasn't an option.

When a nervous system has been in chronic sympathetic activation for long enough, it begins to show up in the body. The symptoms look like this.

Anxiety that has no clear cause, or that is disproportionate to circumstances. Sleep that is poor, fragmented, or unrefreshing even when duration is adequate. Brain fog - the inability to concentrate, to find words, to hold threads of thought. Digestive irregularity. Emotional reactivity that surprises you. Fatigue that rest doesn't resolve. A general sense that your resilience has thinned - that things that used to roll off you now linger for days.

If you are reading both lists and noticing that they are essentially the same list, that is not an accident.

The Overlap That Is Causing Women to Fall Through the Cracks

Here is the clinical reality that is not being communicated clearly enough.

Perimenopause and nervous system dysregulation share a symptom profile that is almost entirely identical. Both produce anxiety, sleep disruption, brain fog, mood instability, fatigue, and digestive issues. Both are influenced by cortisol dysregulation. Both affect the same neurotransmitter systems. Both show up in women at the same life stage - typically the late thirties to mid-forties - because perimenopause begins earlier than most people realise, and because the cumulative load of that decade of adult life tends to land on the nervous system at exactly the same time.

The interaction between them makes things more complicated still.

A dysregulated nervous system amplifies perimenopausal symptoms. Chronically elevated cortisol - the signature of a nervous system stuck in threat mode - disrupts the hormonal cascade that perimenopause is already destabilising. Poor sleep, which nervous system dysregulation produces and perimenopause worsens, depletes both hormonal and neurological resources simultaneously. The anxiety driven by fluctuating progesterone is significantly worse in a nervous system that is already running on a dysregulated baseline. And the cognitive symptoms - brain fog, difficulty concentrating, memory issues - are produced by both oestrogen fluctuation and cortisol excess, compounding in ways that a single-axis explanation cannot account for.

Conversely, perimenopausal hormonal changes dysregulate the nervous system directly. The loss of progesterone's GABA-mediated calming effect means the nervous system has less endogenous capacity to regulate itself. The erratic estrogen fluctuations sensitise the stress response. Women who had relatively regulated nervous systems before perimenopause often find that the transition tips them into dysregulation for the first time.

What this means in practice is that treating hormones alone will help - but may not fully resolve the anxiety, the sleep disruption, or the emotional reactivity, if the nervous system itself is dysregulated and unaddressed. And treating only the nervous system will help - but may not be sufficient if the hormonal foundation is genuinely shifting and those shifts are driving biological changes that nervous system work alone cannot reach.

Both need to be addressed. Not instead of each other. Alongside each other.

Why Women Are Still Being Misdiagnosed

The diagnostic problem here has several layers, and I think it is worth naming them honestly.

The first is that perimenopause is still dramatically under-recognised in clinical settings - particularly in its early stages, and particularly in women under forty. Many doctors have not been trained to consider perimenopause as a possibility in a thirty-seven-year-old, even when the symptom picture is clear. Women at this age are frequently told their hormones are normal - when the relevant point is not the absolute level of hormones at a single blood test, but the pattern of fluctuation over time, which a one-off panel cannot capture.

The second layer is that the nervous system dimension is almost never included in the clinical conversation about perimenopause or in the conversation about anxiety and burnout. A woman presenting with anxiety and fatigue at forty is most likely to be offered antidepressants, a referral to a therapist, or basic lifestyle advice. The possibility that her nervous system is operating from a dysregulated baseline - and that addressing that baseline might be the thing that allows everything else to work better - is rarely raised.

The third layer is the one that lands hardest for the women I work with. When you cannot get a clear explanation for what is happening in your body, when the tests come back normal and the treatments only partially work, the narrative that tends to fill the gap is: the problem is me. I am not coping well enough. I am too sensitive. I should be able to manage this.

That narrative is not the truth. It is the consequence of being under-explained.

How to Think About Where to Start

I want to offer you a practical framework here - not a prescription, because your situation is specific to you and deserves to be treated as such. But a way of thinking about this that might help you navigate a medical and wellness landscape that has not yet caught up to the complexity of what you're experiencing.

Start with a proper hormonal assessment. Not a single blood test, but a conversation with a practitioner who understands perimenopause - ideally a menopause specialist or a gynaecologist with specific training in this area - who can assess your symptom picture longitudinally and who will take your experience seriously rather than defaulting to your age as a reason to look elsewhere. HRT, when appropriate, can be genuinely transformative. It deserves to be properly considered.

Treat your nervous system as part of the picture, not separate from it. Even if the hormonal component is significant, the state of your nervous system will affect how well any intervention works, how severe your symptoms feel, and how quickly your body can stabilise. A chronically activated nervous system makes every perimenopausal symptom worse. Addressing that activation - through consistent regulation practice, sleep prioritisation, and nervous system-informed support - is not optional background work. It is a core part of the intervention.

Take sleep with the seriousness it deserves. Sleep is the place where nervous system regulation and hormonal balance intersect most directly. Poor sleep dysregulates cortisol, worsens hormonal fluctuation, depletes neurological resources, and amplifies every symptom in both categories. Add disrupted sleep from hot flashes or night sweats, and you create a feedback loop - poor sleep leads to higher stress reactivity, which increases anxiety, which worsens sleep. Protecting your sleep is not a lifestyle suggestion. At this life stage, it is one of the most clinically significant things you can do.

Track your symptoms across your cycle. If you are still cycling, even irregularly, your symptoms may show a perimenstrual pattern that gives you information about the hormonal dimension. Nervous system symptoms that are consistently worse in the week before your period, and that lift after it begins, are pointing toward a progesterone-related component. Symptoms that are more consistent across the cycle may have more to do with baseline nervous system dysregulation. Most women have elements of both - and tracking gives you data your doctor can actually use.

Get support that understands both sides. The practitioners most likely to miss something are those who work exclusively in one domain - either hormonal or psychological or nervous system - without understanding how these systems interact. You deserve a practitioner who can hold the complexity of what you are experiencing rather than reducing it to a single explanation.

You Are Not Imagining It. And You Are Not Failing.

I want to close with this, because I think it is the thing most women in this position need to hear most urgently.

The fact that you feel worse than you think you should, and cannot fully explain why, and have been trying hard to manage it without adequate support, is not evidence that you are failing.

It is evidence that you are navigating a genuinely complex biological transition - one that is still under-researched, still under-explained in clinical settings, and still systematically undertreated - without the framework that would make it comprehensible.

What is happening in your body makes sense. The hormonal shifts are real. The nervous system load is real. Their interaction is real. And the fact that the standard medical response has not fully reached it does not mean it cannot be reached.

It means you need a different approach. One that takes both dimensions seriously, addresses them together, and treats you as the specific, complex person you are rather than a set of symptoms to be allocated to a category.

Understand Your Nervous System Pattern First

If you are navigating this transition and want to understand what your nervous system is doing underneath the hormonal picture, the most useful starting point is knowing which pattern your system is running.

My free Nervous System Archetype Quiz takes three minutes. It identifies which of five nervous system patterns you're operating from, what has been maintaining it, and where to begin addressing it - in a way that works alongside, not instead of, any hormonal support you are pursuing or considering.

Take the free Nervous System Archetype Quiz here

And if you are ready for personalised support that holds both the nervous system and the hormonal complexity together, book a free 30-minute discovery call. This is exactly the work I do with women at this life stage - and it is some of the most meaningful work I do.

You are not imagining it. And you are not too much. You are under-supported. That is a solvable problem.

Please note: this article is for informational and educational purposes only. Perimenopause, hormonal changes, and nervous system dysregulation can all overlap with a range of medical and mental health conditions. Nothing in this post constitutes medical advice. Please consult a qualified doctor, gynaecologist, or menopause specialist for an individualised assessment of your symptoms and appropriate treatment options.

Related reading:

Whether it's perimenopause, dysregulation, or both — these 12 signs will help you understand what your body is actually doing:

Nervous System Dysregulation Symptoms: 12 Signs Your Body Is Stuck in Survival Mode

Sleep disruption is one of the most common symptoms at this life stage — and one of the most fixable: Why You're Exhausted But Can't Sleep — And It Has Nothing to Do With Your Bedtime Routine

Living and working in sync with your cycle is one of the most powerful tools for women in their late 30s and beyond.

Download the free guide: Aligned Living — Train, Work & Live In Sync With Your Cycle

For a complete framework that addresses stress, sleep, movement, nutrition, and connection together — the Calm & Resilient course was built for exactly where you are right now.