New research has suggested that women who have had multiple children could, in fact, be at a reduced risk of dementia.
The discovery came after experts found that higher exposure to oestrogen throughout a woman's life could actually lead to them having a healthier brain. They found that people with a longer "reproductive lifespan", or those who have had several children, will accumulate more exposure to the hormone.
Researchers found that this appears to correlate to a lower risk of cerebral small vessel disease. The condition comes as a result of damage to the small blood vessels in the brain and is linked to cognitive impairment and dementia.
They looked at 9,000 women who had been through the menopause with an average age of 64 in the UK. The women answered detailed questions on reproductive health - including the age of their first period when they started menopause and how many pregnancies they had.
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Getty Images)The women also had brain scans carried out to look for cerebral small vessel disease. The researchers then calculated their lifetime hormone exposure by adding the number of years they were pregnant to the duration of their reproductive lifespan (the number of years between their first period and when they began menopause).
Of the 9,000 women, the average lifetime hormone exposure was 40 years. According to the analysts, those with a higher lifetime hormone exposure had lower white matter hyperintensity volumes - which is an indicator of cerebral small vessel disease.
The researchers also found that taking oral contraceptives, or HRT, did not seem to alter the beneficial effects of pregnancies or reproductive lifespan. Kevin Whittingstall, one of the study's authors from the University of Sherbrooke in Quebec, Canada, said: "Our study highlights the critical role of reproductive history in shaping the female brain across the lifetime."
In an article for the journal Neurology, he added that the results "emphasise the need to integrate reproductive history into managing brain health in postmenopausal women". Earlier studies have shown that rates of certain diseases, including cerebral small vessel disease, increase after menopause, which is often linked to the absence of hormones.
Before this latest discovery, it was unknown whether the amount of exposure to hormones before menopause extended the window of protection afterwards. A separate study from 2021 found that women who had been exposed to higher amounts of oestrogen throughout their lies have larger volumes of grey matter in their brains.
Grey matter is a major part of the nervous system. It is involved in sensory perception, such as seeing and hearing, memory, speech and decision-making.
Researchers from Weill Cornell Medicine in New York found that for every extra year a woman was exposed to oestrogen in her life, the average grey matter volume in certain areas of the brain increased by one per cent. With each additional child a woman had, the volume of grey matter rose by an average of two per cent.
