Perimenopause symptoms
Brain fog and memory
Cognitive symptoms during perimenopause
You reach for a word that has always been there and it isn't. You walk into a room and the reason dissolves before you arrive. You read the same paragraph three times and retain nothing.
And underneath all of it, a thought you may not have said out loud: is this how it starts? If you have been frightened by changes to your memory, concentration, or mental sharpness, this page is for you. Because what you are describing has a name, a well-researched cause, and, for most women, a course that does not lead where you fear it might.
Oestrogen is not only a reproductive hormone. It has receptors throughout the brain and plays a role in how neural circuits function — including those involved in memory, attention, and processing speed. Longitudinal research from the SWAN study found real, measurable changes in cognitive performance during perimenopause, particularly in verbal learning, verbal memory, and processing speed — not explained by ageing alone. Crucially, the same research found these changes were time-limited for many women: cognitive performance showed signs of rebounding after the transition to postmenopause.
The cognitive changes of perimenopause are not the early signs of dementia. Dementia involves progressive, accumulating damage to brain tissue. What happens in perimenopause is a different process — a response to changing hormone levels that, for most women, stabilises or partially reverses after the transition. The fear is understandable. But the evidence does not support it as the likely explanation.
A quality of mental dullness or slowness that doesn't respond to rest. The sense of needing more effort than usual for tasks that used to feel automatic. Not inability — effort.
Misplacing things you never used to misplace. Forgetting the content of a conversation hours after it happened. Research consistently identifies verbal memory — used for names, words, and recent events — as the domain most affected.
Difficulty staying on task, especially with reading, sustained attention, or complex work. Being pulled off track more easily than before, and finding it harder to get back.
Reaching for a specific word and meeting a gap. Knowing the concept, knowing you know the word, but being unable to retrieve it in the moment. One of the most distressing cognitive symptoms because it is visible to others.
Finding decisions that would once have been easy now require more time and feel less clear. Difficulty switching quickly between tasks or holding multiple things in mind simultaneously.
Cognitive complaints are among the most frequently reported symptoms of perimenopause. A 2023 review in Current Psychiatry Reports confirmed that cognitive problems are common during perimenopause with significant impact on a substantial proportion of women. Depression, sleep disruption, and vasomotor symptoms are all associated with cognitive complaints during this period — creating a situation where several causes overlap and amplify each other.
Sleep is the most significant compounding factor. The cognitive changes of perimenopause and the sleep disruption of perimenopause are deeply connected — sleep deprivation of any cause worsens every dimension of cognitive performance. Mood also matters. Low mood, anxiety, and the emotional weight of multiple concurrent symptoms all reduce cognitive capacity — not as imagination, but as a measurable consequence of the mental resources they consume.
Cognitive symptoms are easy to underreport because they carry shame and fear. Women often minimise them in appointments, or fail to mention them at all, because they are afraid of what an assessment might show. But these changes are a legitimate part of perimenopause and belong in the conversation. It helps to describe when they started relative to other changes — in periods, in sleep, in mood — and to be honest about the fear underneath them, if it's there.
Mind and memory is one of the eight domains in the Thea Klara survey. The survey covers brain fog, concentration, forgetfulness, word finding, and difficulty with decisions — mapping the full cognitive picture rather than asking only about memory.
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Metcalf CA et al. Cognitive Problems in Perimenopause: A Review of Recent Evidence. Curr Psychiatry Rep. 2023.
Greendale GA et al. Menopause-associated Symptoms and Cognitive Performance. SWAN / Am J Epidemiol. 2010.
Weber MT et al. Cognition and Mood in Perimenopause. J Steroid Biochem Mol Biol. 2014.
Maturitas clinical review on menopausal brain fog, counseling and treatment. 2024.
Thea Klara provides self-advocacy tools, not medical advice. This content has been written to help you understand and describe your experience. It is not a substitute for a conversation with a qualified healthcare professional.