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Clearing the fog

Free health articles | Research 31 Aug 2020

Finding it hard to concentrate at certain times of the month? Your hormones could be causing brain fog.

In the days leading up to their periods, many premenstrual women have long complained about poor concentration, having trouble remembering things, even struggling to make a decision. It’s called brain fog or ‘brain fatigue’ and has finally become a serious topic in women’s health.

What causes brain fog?

The latest theory is that there is a link between a woman’s sex hormones – primarily oestrogen and progesterone – and her ability to think, learn and understand, known as cognition skills.

The menstrual cycle creates fluctuations in levels of these hormones. And the more severe a woman’s premenstrual symptoms are, the more likely they are to experience changes in their cognition skills, or brain fog, says Associate Professor Caroline Gurvich, a Senior Research Fellow and Clinical Neuropsychologist at Monash Alfred Psychiatry (MAP) Research Centre.

Assoc Prof Gurvich estimates that about 80% of women have at least one symptom, physical or psychological, before they get their period. Up to 8% of women suffer from premenstrual dysphoric disorder (PMDD), a significantly more severe form of premenstrual syndrome (PMS) that can cause debilitating emotional and physical symptoms.

“Sex hormones affect the way we think,” says Assoc Prof Gurvich. “The effects across the menstrual cycle can be very subtle. Women who are more sensitive to hormone fluctuations are probably more likely to experience brain fog, but we don’t know that for sure.”

Brain fog is yet to be formally recognised as a medical or psychological condition, but the good news is that it is finally being acknowledged. “It is real,” says Assoc Prof Gurvich. “Our hormones that regulate our reproductive functions have direct effects in the brain and affect brain regions that are involved in our thinking skills.”

Why has it been neglected as an area of research?

Assoc Prof Gurvich says the view that premenstrual brain fog is just “women’s business” has damaged the capacity for research in the field. “But we need to understand this for everyone’s sake,” she says.

So, what is happening on the research front?

Researchers are trying to establish what factors contribute to brain fog or cognitive changes. Assoc Prof Gurvich and a team that includes Dr Natalie Thomas, a Research Fellow at MAP Research Centre, have started a study that hopes to better understand the link between hormones that regulate the menstrual cycle, hormones that regulate the stress system, mood and thinking skills.

Dr Thomas says 100 women will take part in the study, comparing hormone levels, mood and thinking skills in women who experience no symptoms of premenstrual stress, to women who experience significant levels of premenstrual stress.

She says researchers will also examine whether exposure to early life stress or trauma can contribute to women becoming more sensitive to hormone fluctuations across the menstrual cycle.

“There is research to suggest that exposure to early life stress can alter the regulation of stress hormones,” says Dr Thomas. “Changes in stress hormone levels can also contribute to women being more sensitive to hormone fluctuations that occur across the menstrual cycle.”

What to do about brain fog

There are a few easy things you can do yourself to reduce your likelihood of brain fog, says Jean Hailes endocrinologist Dr Sonia Davison. Here are her tips:

  • Eat healthily – fruit and vegetables, lean meat. Choose low-fat, high fibre, low GI foods. Try to ignore cravings for highly processed and sweet or salty foods.
  • Avoid too much caffeine and alcohol.
  • Regular exercise, including walking.
  • Try to sleep well.
  • Try to avoid stressful situations.
  • Make sure you are not suffering from other medical issues such as iron deficiency, low vitamin D, or anaemia. Your doctor will guide you on these issues.
  • Try not to be too hard on yourself.

When to see your doctor

Dr Davison says it may be necessary to seek medical treatment if these self-help steps do not help to improve your quality of life.

She says some women benefit from evening primrose oil or a multi B vitamin. But the most effective treatments for PMDD include taking antidepressants (from the SSRI group that increase serotonin levels), and regulating hormones by using the combined oral contraceptive pill or vaginal contraceptive ring.

“The latter strategy should ‘switch off’ a woman’s ovarian hormones temporarily and give her a steady flow of hormones to avoid fluctuation, which is a key goal,” says Dr Davison. “The key is to persevere for at least two to three months, as it can take this long for the ovarian hormones to stop being produced.”

For more information on managing premenstrual symptoms, visit our page on Premenstrual syndrome (PMS).

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Last updated: 
18 January 2024
Last reviewed: 
01 March 2024