Why Thyroid Problems and Autoimmunity Often Flare During Perimenopause
Many women arrive in perimenopause expecting hot flushes and irregular periods.
What they don’t expect is for long-standing allergies to worsen, Hashimoto’s disease to appear, or for thyroid symptoms to suddenly become much harder to ignore.
If you’ve found yourself wondering whether it’s hormones, your thyroid or something else entirely, you’re not alone.
Perimenopause is more than a reproductive transition. It’s also a time of immune and metabolic recalibration.
Having lived with autoimmune thyroid disease and now navigating perimenopause myself, this is a topic I’ve become deeply interested in, not just professionally, but personally.
Key Takeaways
✔ Thyroid conditions often become more noticeable during perimenopause.
✔ Hormonal changes can influence thyroid function and immune activity.
✔ Symptoms of thyroid dysfunction, insulin resistance and perimenopause often overlap.
✔ Autoimmune thyroid disease is common in women over 40.
✔ Looking beyond hormones can help identify other contributors to symptoms.
Are Your Symptoms From Hormones Or Something Else:
I don’t see perimenopause as an ending. I see it as a period of recalibration.
During the recalibration that is perimenopause, existing vulnerabilities often become more obvious. That vulnerability could involve the thyroid, blood-sugar regulation, an autoimmune condition, nutritional status, chronic stress, or several of these interacting at once.
Thyroid disease, insulin resistance and autoimmune conditions don’t necessarily begin in perimenopause, but this transition can reveal them.
Perimenopause doesn't create every problem.
One of the biggest mistakes I see in clinic is women assuming every symptom is “just hormones.”
Sometimes hormones are the main driver.
Sometimes thyroid dysfunction is.
Sometimes insulin resistance.
Sometimes chronic stress.
And very often, it’s several things interacting.
That’s why I don’t like chasing individual symptoms.
I prefer understanding the whole picture.
Perimenopause As A Time Of Immune Recalibration
I often describe perimenopause as a time of immune recalibration.
That is not a medical diagnosis. It is a way of explaining how changing hormone patterns may influence the systems that regulate inflammation, immune activity and resilience.
Immune cells have receptors for sex hormones, which means changes in oestrogen and progesterone can affect how the immune system communicates and responds. Research suggests that the menopausal transition is associated with changes in inflammatory signalling and immune function, although we are still learning exactly what this means for individual autoimmune conditions.
This does not mean perimenopause causes every new symptom or autoimmune condition. But it may help explain why some women notice worsening allergies or inflammatory symptoms during midlife.
If you’re experiencing worsening allergies or histamine-related symptoms, you might also find my article on histamine and perimenopause helpful.
Perimenopause Hormone Shifts
The menopause transition is associated with changes in body-fat distribution and metabolic health.
Fluctuating oestrogen, declining progesterone, disrupted sleep, changes in body composition and a reduced ability to compensate for stress may place more pressure on systems that were already vulnerable.
‘Perimenopause may not create every problem, but it can reveal where the body was already struggling to compensate’
This is why a problem that was previously mild, well managed or barely noticeable can suddenly become harder to ignore.
‘I often think of perimenopause as a period when the foundations become less stable’
The body is recalibrating to new levels of hormones, and during that transition, existing issues with thyroid function, blood-sugar regulation or immune activity may rise to the surface.
Thyroid Dysfunction In Perimenopause
The thyroid helps regulate energy production, temperature, digestion, mood, heart rate and many other functions. Thyroid hormone receptors are widely spread throughout the body much like sex hormone receptors.
This is why thyroid dysfunction can look remarkably similar to perimenopause. Fatigue, changes in weight, poor concentration, sleep disturbance, altered menstrual bleeding, low mood and hair changes may occur in both.
The relationship between reproductive hormones and thyroid function is complex, with each influencing the other. During perimenopause, changing hormone patterns may affect how thyroid hormones are transported and used, while autoimmune thyroid disease may become more noticeable during this period of hormonal and immune recalibration.
What Is Thyropause?
Thyropause is not a medical diagnosis. It is an informal term used to describe the overlap between perimenopause and declining or disrupted thyroid function.
The symptoms can be remarkably similar. Fatigue, brain fog, weight changes, hair loss, mood changes, altered periods and changes in cholesterol may occur with perimenopause, thyroid dysfunction or both.
This overlap can make it easy to assume that every new symptom is caused by reproductive hormones.
Maybe it is.
But maybe an already existing thyroid condition has become more noticeable.
Sometimes thyroid dysfunction is developing at the same time that hormones are shifting.
And sometimes both systems are contributing.
‘Rather than describing a new disease, thyropause is a helpful way of describing the overlap between changing hormones and thyroid function during midlife’.
Insulin Resistance & Perimenopause
Insulin resistance can also sit quietly beneath symptoms that are blamed on perimenopause.
Insulin is the hormone that helps move glucose from your bloodstream into your cells to be used for energy. When your cells become less responsive to insulin, your body has to work harder to keep blood sugar under control.
Women with insulin resistance may notice:
- increasing abdominal weight
- difficulty losing weight
- energy crashes
- cravings
- elevated triglycerides or cholesterol
- rising blood glucose
- fatigue or brain fog
Many of these symptoms overlap with both perimenopause and thyroid dysfunction, which can make it difficult to know what is driving what.
That is why I prefer to look at patterns rather than isolated symptoms.
Weight gain, fatigue or brain fog may be hormonal.
They may also be metabolic.
Often, they are influenced by both.
They are a sign that the internal environment has changed and the strategy needs to change with it. What worked for you before may no longer.
| Symptom | Perimenopause | Thyroid | Insulin Resistance |
|---|---|---|---|
| Fatigue | ✓ | ✓ | ✓ |
| Weight gain | ✓ | ✓ | ✓ |
| Brain fog | ✓ | ✓ | ✓ |
| Hair loss | ✓ | ✓ | |
| Heavy periods | ✓ | ✓ | |
| High cholesterol | ✓ | ✓ |
The Autoimmune Connection
Perimenopause is also a time of immune recalibration.
Immune cells have receptors for sex hormones, so changes in oestrogen and progesterone can influence inflammatory signalling and immune activity.
Women make up around 80% of people living with autoimmune disease, although the balance varies between conditions.
Hashimoto’s disease is especially relevant because it affects the thyroid and is far more common in women.
Hormonal change does not automatically cause autoimmune disease. However, it may alter the environment in which an existing vulnerability is expressed.
Perimenopause may not create an autoimmune vulnerability, but it can change the environment in which that vulnerability comes to the surface.
What I See In Clinic
Very rarely is there one single answer.
Sometimes hormones are the biggest driver.
Sometimes thyroid dysfunction.
Sometimes insulin resistance.
Sometimes nutrient deficiencies or chronic stress.
Often it’s several things interacting.
That’s why I step back and look at the whole picture before deciding where to focus.
Wondering If Your Symptoms Are Hormones, Thyroid Or Something Else?
If you’ve been told your symptoms are “just perimenopause” or offered no answer at all, it’s worth looking at the bigger picture.
Hormones matter – but they’re rarely the whole story.
Thyroid health, metabolic health, immune function and the foundations that support them all deserve consideration too.
If you’re struggling to make sense of your symptoms, and are not sure where to start, I can help you look beyond hormones and identify the factors that may be contributing.
Together we’ll explore your health history, symptoms, nutrition, lifestyle and relevant testing to build a personalised plan that supports your long-term health and fits your lifestyle.
👉 Book an online consultation to get started.
FAQ's On Thyropause & The Immune System In Perimenopause
Yes. Hormonal fluctuations during perimenopause can influence thyroid hormone availability and may make existing thyroid issues more noticeable. Perimenopause can also coincide with the development or progression of autoimmune thyroid disease in some women.
Thyropause is a term sometimes used to describe changes in thyroid function that can occur around perimenopause and menopause. It isn’t a formal medical diagnosis, but it reflects the close relationship between sex hormones and thyroid hormones.
Perimenopause doesn’t necessarily cause Hashimoto’s disease, but hormonal changes may contribute to a flare or bring an underlying autoimmune process to light in women who are genetically susceptible.
Thyroid antibodies aren’t included in routine thyroid screening. Depending on your symptoms and history, they may provide useful information, particularly if autoimmune thyroid disease is suspected.
Yes.
Fatigue, weight gain, brain fog, mood changes, heavy periods and hair loss can occur in both thyroid dysfunction and perimenopause, which is why looking at the whole clinical picture is important.
References:
Mintziori G, Veneti S, Poppe K, et al. (2024). EMAS Position Statement: Thyroid Disease and Menopause. Maturitas, 185, 107991.
Taylor PN, Lansdown A, Witczak J, et al. (2023). Age-related variation in thyroid function: A narrative review highlighting important implications for research and clinical practice. Thyroid Research, 16, 7.
Brown EDL, Obeng-Gyasi B, Hall JE, Shekhar S. (2023). The thyroid hormone axis and female reproduction. International Journal of Molecular Sciences, 24(12), 9815.
Chaker L, Bianco AC, Jonklaas J, Peeters RP. (2017). Hypothyroidism. The Lancet, 390(10101), 1550–1562.
Gameiro CM, Romão F, Castelo-Branco C. (2010). Menopause and aging: Changes in the immune system—a review. Maturitas, 67(4), 316–320.
Desai MK, Brinton RD. (2019). Autoimmune disease in women: Endocrine transition and risk across the lifespan. Frontiers in Endocrinology, 10, 265.
