Roughly two-thirds of women complain of forgetfulness or “brain fog” during menopause. Now two new studies add to the growing body of research suggesting that cognitive decline and memory problems associated with menopause are real and may be linked to fluctuating levels of hormones in the brain.

In one study, pre- and post-menopausal women performed worse on tests of memory and cognition in the year after they had their last period than in the time leading up to menopause. Researchers at the University of Rochester in New York performed a battery of cognitive tests on 117 women ages 40 to 60 who were in various stages of menopause.  The researchers found that in their first post-menopausal year, women performed significantly worse on tests of verbal learning and memory (how well they could recall words from a list), motor function (how fast they could place a series of grooved pegs in a pegboard), and attention and working memory (how well they could recall increasingly longer strings of digits) than women who had not yet reached menopause. These effects were large for verbal learning and memory; medium for fine motor skills; and small to medium for attention and working memory. The study was published in January in the journal Menopause.

While it is unclear why menopause may affect cognition, hormones most likely are involved, according to the researchers. “In the months after a woman has her last period, hormonal changes are most abrupt,” said senior study researcher Pauline Maki, director of women’s mental health research at the University of Illinois at Chicago. As a woman approaches menopause, the ovaries gradually produce less estrogen, which is crucial for thinking and remembering.

Luckily, changes in memory associated with menopause appear to be temporary and are not linked to diseases such as dementia and Alzheimer’s disease, Maki said. But the study confirms that the complaints expressed by many menopausal women are the result of real cognitive deficits and aren't just in their heads, Maki said.

The second study, led by researchers at Brigham and Women’s Hospital in Boston, suggests that the younger a woman is when she experiences surgical menopause — the removal of her uterus (hysterectomy) and one or both ovaries (oophorectomy), the faster she experiences declines in her ability to remember times and places and understand basic concepts as well as her overall cognition. What's more, the study found, she is at greater risk for the development of brain lesions called plaques, which have been associated with neurological diseases such as Alzheimer's. However, the researchers found no link between a woman's age at surgical menopause and Alzheimer’s disease.

More than 1,800 postmenopausal women, whose average age was 78 when the study began, were involved in the research. One-third of the women reported having previously undergone surgical menopause. The remaining two-thirds had experienced natural menopause.

Previous studies have suggested that women who experience surgical menopause prior to the age of natural menopause are vulnerable to changes in the brain that may alter cognitive function over the long term. On average, most American women experience their last period at about age 51, according to the National Institutes of Health.

Women who underwent a hysterectomy and oophorectomy, but took hormone replacement therapy, had a slower rate of cognitive decline than women who did not take hormones. The study did not quantify the amount of time a woman would have to take hormones to experience such a benefit.

“These are preliminary data and do not warrant any new medical advice at this time,” said study author Dr. Riley Bove, a neurologist at Brigham and Women’s Hospital. “Further research needs to be conducted to evaluate the neuroprotective effects of hormone replacement therapy after early surgical menopause.”

Many menopausal women are bothered by symptoms such as hot flashes, night sweats, sleep problems and depression. Some experts hypothesize that these symptoms may contribute to memory problems.

To ease menopausal symptoms, women may be prescribed hormone replacement therapy. Those women who still have a uterus are typically prescribed a combination of progesterone and estrogen; women who no longer have a uterus are prescribed only estrogen.  However, hormones have both benefits and risks, such as an increased risk for breast cancer and stroke.

“At this time, there’s no indication to use hormone replacement therapy for the sole treatment of memory problems in natural or surgical menopause,” said Maki.

Findings from the second study, which have not been published in a peer-reviewed journal, will be presented at the annual American Academy of Neurology conference in San Diego in March.

Pass It On: Two studies confirm that memory problems are common during menopause.

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