The brain fog of menopause

YOUR BRAIN ON MENOPAUSE: In this seven-part series, I explore menopause from a brain health perspective with a particular focus on the neurobiology of hot flashes, sleep, mood and memory, the role of hormone therapies and their long-term effects on the brain. This is Part 5.

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This is a long and detailed read. Click here to download the series as a PDF to read offline.

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Brain fog during menopause is common

Memory loss and brain fog are very common experiences for women going through the menopause transition.

And one of the fears midlife women have is whether their foggy brain is an early sign of an inevitable decline towards dementia.

When I was writing my book on women’s brain health, I spoke to a friend who is a dementia researcher in her late 40s. She confessed to she’d visited her GP to discuss symptoms as she was terrified she had early-onset dementia. Her fears were not unfounded —menopausal brain fog and early-stage dementia share many of the same symptoms, including those my neuroscientist friend had a detailed professional understanding of.

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But, it is important to know that brain fog is not an early sign of dementia.

Menopausal brain fog is temporary and typically disappears after the transition is over.

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Obstetrician and gynaecologist Jen Gunter who has written the excellent book The Menopause Manifesto, likens brain fog and the hormonal chaos of the menopause transition to a computer uploading a new program:

“During the upload (the menopause transition) things run a little slower. Once loaded, there may be a glitch or two before this new program is running smoothly and then things settle as the new program takes over. After all, both computer code and hormones are forms of language.”

Jen Gunter, The Menopause Manifesto

What are the symptoms of brain fog?

‘Brain fog’ is an umbrella term used to describe problems with memory or concentration.

Symptoms may include:

• Slow or fuzzy thinking
• Problems finding the ‘right’ word or remembering names
• Difficulty focusing
• Confusion
• Forgetfulness.

Professor John Eden, a gynaecologist and reproductive endocrinologist and director of Women’s Health and Research Institute of Australia (WHRIA), told me a change in ‘word-finding ability’ is common in the women he treats. He mentioned lawyers, in particular, notice this symptom early, presumably because they rely so heavily on verbal gymnastics and sharp recall!

Research suggests that brain fog is a real but temporary experience for some women.

Approximately 60% of women over 40 report experiencing brain fog. While some clinical studies support these subjective experiences, others find that cognitive testing often doesn’t detect subtle or measurable changes in cognition. This discrepancy is good news, as it suggests that while many women perceive a decline, it may not necessarily indicate significant cognitive impairment.

• A 2014 meta-analysis compared young healthy fertile women with peri- and post-menopausal women. Post-menopausal women performed significantly worse than fertile and perimenopausal women on verbal memory tasks (i.e remembering a list of words or a story).
• A 2019 systematic review and meta-analysis of women undergoing surgical menopause (ovaries removed for cancer treatment) show a faster decline in various tests of memory and accumulation of Alzheimer’s neuropathology.
• A group of Harvard researchers compared memory in men and women ages 45 to 55 using a range of cognitive task. Women’s memory skills declined slight over the menopause transition. But, at all ages, regardless of menopausal status, women outperformed men! This cognitive advantage persists in women with a dementia diagnosis.
• A paper published in Nature Scientific Reports in 2021 by Lisa Mosconi and her team carefully charting the brain changes that take place across the menopausal transition. They found no differences in ‘global cognition’ scores between pre-, peri- and post-menopausal women.

Four cognitive trajectories through menopause

Like other major life changes, menopause encompasses a wide range of experiences that are very different for each woman.

Rather than generalising or averaging the cognitive changes experienced by all women, it is more insightful to consider ‘groups’ or subsets. This approach allows us better to understand the range of cognitive profiles and experiences.

Let’s consider the different cognitive profiles that appear during this important time by looking at specific data from a small but insightful study. The 2021 study by Pauline Maki and colleagues tracked 87 perimenopausal women, each undergoing detailed cognitive testing twice annually over several years, generating 415 observations. The researchers applied machine learning (AI) techniques and statistical modelling to identify four distinct groups of women.

• Cognitively Normal: This group, representing approximately 40% of women, maintain normal functioning across all cognitive tests during perimenopause.
• Verbal Learning and Memory Challenges: Including about 20-30% of the women, this group experience specific difficulties with verbal learning and memory and report more sleep disturbances than other groups.
• Verbal Learning and Memory Strengths: About 20-30% of the women experience enhanced verbal learning and memory abilities. These women experience fewer depressive and hot flash symptoms.
• Attention and Executive Function Strengths: About 10% of women demonstrate strong performance in attention and executive functioning tasks. The women report less sleep disturbance

These four profiles show how memory and ‘brain fog’ experiences can vary among women during menopause, highlighting the individuality of each woman’s experience.

The study also identified potential protective factors:

• Hormonal Variability: Differences in oestrogen and follicle-stimulating hormone levels.
• Physical Symptoms: Sleep disturbances, depressive symptoms, & hot flashes significantly influenced cognitive changes.
• Education: Higher levels of education were associated with better cognitive performance, highlighting the role of cognitive reserve.

By focusing on these groups rather than averaging over everyone, we can appreciate the individuality of each woman’s experience, acknowledging both cognitive resilience and vulnerability.

Why do some women experience temporary brain fog during the menopause transition?

When writing my book, I had numerous conversations with researchers and clinicians about menopausal chicken and egg scenarios. One likely explanation is the well-established link between sleep and brain fog. Some research attributes memory lapses and inability to concentrate to disrupted sleep, especially in women who have hot sweats and night sweats.

In a previous blog post Menopause And Sleep Problems: Are You Too Hot To Sleep?, I discussed how fluctuating levels of oestrogen can disrupt thermoregulation circuits in the hypothalamus and the knock-on effect on sleep.

I’ve asked numerous women’s health clinicians if hot flashes and sleep problems contribute to brain fog. Most experts simply concluded brain fog symptoms, sleep and hot flashes are “linked.”

Sonia Davison, consultant neuroendocrinologist to the Jean Hailes Foundation wrote in an email,

“Hot flashes and sweats, sleep disturbance, low mood and anxiety, all can have a negative impact on higher brain function.”

Sonia Davison, consultant neuroendocrinologist to the Jean Hailes Foundation

Professor Sue Davis from Monash University chatted to me over the phone, and said,

“You can’t dissect out hot flashes and sweats from sleep disturbance. We know sleep is really important for consolidation of memory.

But is brain fog due to disturbed sleep, anxiety, or hormones? We just don’t know.”

Sue Davis from Monash University

And Jen Gunter writes in The Menopause Manifesto,

“Women who are under more stress, have depression or anxiety, have other health concerns, or who aren’t sleeping well and/or who have more vasomotor symptoms are more likely to judge their cognitive performance more harshly.

Vasomotor symptoms can even prime the brain to be more receptive to negative experiences. This is the mind-body connection in action.”

Jen Gunter writes in The Menopause Manifesto

What about the relationship between ovarian hormones and cognition?

Neurally speaking, oestrogen keeps your brain healthy.

As discussed in the blog post ‘Are your menopause symptoms all in your head? Or brain?’, oestrogen enables sharp thinking by promoting neuron and synapse growth and survival.

We know exactly what happens in rats and mice — when oestrogen surges during the oestrous cycles of rodents, dendritic spines from the hippocampus and prefrontal cortex flourish. The spines are later pruned away as oestrogen levels wane.

Dramatic pruning of spines is seen in menopausal monkeys and rats who’ve had their ovaries removed. And in both monkeys and rats spine pruning is correlated with worse memory. We have no idea if this is the case in women going through menopause, but is certainly plausible.

We also understand that oestrogen supports the biochemical pathways that use insulin and generate energy from glucose. Changes in oestrogen may change how efficiently neurons use glucose and in turn memory and attention.

Mosconi’s 2021 research provides strong support for this notion. Glucose metabolism slowed in the brains of post-menopausal women. However, the brain compensated for this slowing by increasing blood flow and increasing ATP metabolism.

Mosconi suggests instead the brain cleverly compensates for changing hormone levels, and finds a ‘new normal’ after menopause.

“…human menopause is a dynamic neurological transition that reshapes the neural landscape of the female brain during midlife endocrine aging, and provide preliminary evidence for an adaptive process serving the transition into late life.”

Mosconi et al, 2021

Does hormone therapy fix brain fog?

Rather annoyingly (!), the evidence is mixed and leans towards menopausal hormone therapy (MHT) not clearing brain fog.

Some women who start taking MHT have found no benefit (and no risk) to cognition. But for others, once their sleep improves their brain fog clears.

You can read more from two different trials here and here.

Speaking to Scientific American, Victor Henderson, a neurologist at Stanford University who worked on one of the trails,

“Our results suggest that there’s no reason for healthy women to consider taking hormone therapy to improve memory, regardless of their age.

On the other hand, if women are considering taking hormone therapy for approved indications such as treatment of moderate-to-severe hot flashes and night sweats or for osteoporosis prevention, then they don’t need to be overly concerned about negative effects of estrogen on memory.”

Victor Henderson, Scientific American

For younger women who experience surgical menopause to remove their ovaries (as part of cancer treatment or other health issues), surgery results in a sudden and dramatic reduction of levels of ovarian hormones including oestrogen. These women experience various health consequences including declines in learning and remembering words.

Again, clinical trials have failed to show any benefit of hormone therapy on cognition (but keep in mind this is different from ‘brain fog’. But work is continuing on the importance of timing of hormone therapy especially in women who have their ovaries removed in their 20s, 30s and 40s.

“MHT may correct the memory deficit directly, but the improved cognition may be due to improvement in other symptoms that are synergistic in exacerbating the memory loss such as sleep deprivation and hot flushes.”

Australian Menopause Society

What lifestyle changes help lift brain fog during menopause?

If hormone therapy doesn’t help with brain fog. What can you do?

Jen Gunter offers the following suggestions in The Menopause Manifesto:

• Be reassured: temporary changes with memory, attention, and the feeling of brain fog are typical symptoms of the menopause transition, and while they feel alarming they aren’t a cause for alarm. This isn’t a sign that there’s a steep memory cliff ahead.

• Consider asking your GP for help with depression, anxiety, and sleep disturbance: these affect cognitive performance and when treated memory may improve.

• Exercise: at least 150 minutes a week of moderate activity is the goal. Moving your body is the best exercise you can provide for your brain.

• Consider stress: there’s no easy fix here, but a psychologist may be able to help reframe life stressors, give support, and provide strategies for coping.

I’ll also add data from Pauline Maki’s study that highlights the importance of sleep.

If you’re a in the midst of midlife, think about what you have going on. Are you raising teenagers? Home schooling younger children? Worrying about ageing parents overseas? Juggling work? Keeping your marriage on track? Having an existential about the pandemic and/or climate change? All of these factors undoubtedly increase stress and exacerbate the cognitive blips you’re experiencing.

How do I know if I have brain fog or dementia?

When I posed this question to Professor John Eden at WHRIA, he answered that it can be difficult, and often the simplest way to find out is to give women two months of hormone therapy and see if their symptoms improve (presumably as a consequence of improved sleep).

The symptoms of dementia and brain fog may be similar, but remember that dementia is a disease of unhealthy ageing.

Jen Gunter reminds us that dementia is uncommon in women in their 40s and 50s, and men of the same age rarely worry about memory lapses, she notes,

“The way we think about menopause feels like an exercise in confirmation bias about the supposed ineptitude of older women.”

Jen Gunter, The Menopause Manifesto

Dementia often begins with lapses in memory and difficulty in finding the right words for everyday objects, and according to Alzheimer’s Australia, other symptoms may include:

• Persistent and frequent memory difficulties, especially of recent events
• Vagueness in everyday conversation
• Apparent loss of enthusiasm for previously enjoyed activities
• Taking longer to do routine tasks
• Forgetting well-known people or places
• Inability to process questions and instructions
• Deterioration of social skills
• Emotional unpredictability

It is important to realise a certain degree of forgetfulness is normal at any stage of life. We all have ‘tip-of-the-tongue’ moments, call our children by the wrong name, or can’t remember why we walked into a room. We just tend to become more conscious of them and fret over moments of memory loss the older we get.

As a rule, normal memory loss involves forgetting to add the eggs when you’re baking a cake. Dementia involves opening a box of eggs and not knowing what to do with them.

Similarly, normal memory loss involves forgetting where you put your car keys. Dementia involves not know what your keys are for when you eventually find them.

As always, call your doctor if memory changes come on suddenly, or are accompanied by hallucinations, paranoia, or delusions, affecting your ability to drive or cook safely.

The final big question: does menopause hormone therapy cause or prevent dementia?

So far the focus of this article is on MHT and brain fog. Remembering that brain fog is not the same as cognitive decline or dementia.

Whether MHT provides protection against cognitive aging and Alzheimer’s disease remains unclear.

Overall, hormone therapy’s efficacy is thought to depend on the timing of when you start taking it with respect to age at menopause – the so-called critical window theory whereby the earlier you start treatment the safer. This is especially the case for younger women who have surgical menopause.

For older women who start taking hormone therapy after the age of 65 (and outside the ‘critical window’ when it is deemed safe), they experience accelerated cognitive decline (decline in thinking, language, memory, understanding, and judgment) and dementia.

And the official line on menopause hormone therapy (MHT) from the Australian Menopause Society

• At present, it is premature to recommend MHT for cognitive function until more substantiated clinical correlates are available.
• Lessening vasomotor symptoms with MHT or non-hormonal treatments may improve cognitive function.
• Improving sleep, using mnemonic devices or engaging in physical activity may also lessen menopause transition cognitive deficits.
• Cognitive testing is not indicated unless the symptoms are progressive and interfere with work performance or relationships.

And I’ll leave the last word to the heroic Jen Gunter,

“…many harmful cultural narratives tie a woman’s competence to her hormones. We’re accused of being too hormonal before each period, during our period, during pregnancy, and after having a baby.

And what happens when we finally rid ourselves of these supposedly toxic hormones? Our brains are now supposedly unable to function.

Girls have amazing, capable brains before they enter puberty and many women who never take estrogen continue to achieve great things after their final menstrual period.”

The Menopause Manifesto

YOUR BRAIN ON MENOPAUSE: In this seven-part series, I explore menopause from a brain health perspective with a particular focus on the neurobiology of hot flashes, sleep, mood and memory, the role of hormone therapies and their long-term effects on the brain. This is Part 5.

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This is a long and detailed read. Click here to download the series as a PDF to read offline.