During menopause, which marks the end of a woman’s menstrual cycle, her ovaries stop producing the hormones estrogen and progesterone, ending her natural childbearing years. But these hormones also regulate how the brain works, and the brain controls their release – meaning menopause is also a neurological process. “Many of the symptoms of menopause are impossible to produce directly from the ovaries when you think of the hot flashes, night sweats, anxiety, depression, insomnia, brain fog,” says Lisa Mosconi, associate professor of neurology at Weill Cornell Medicine and director of the Women’s Brain Initiative. “These are brain symptoms, and we should think of the brain as something that’s at least as badly affected by menopause as your ovaries.”
In June, Mosconi and her colleagues published one of the few studies in the journal Scientific Reports that looked in detail at what happens to the brain during the menopause transition, not just before and after. Using various imaging techniques, they scanned the brains of more than 160 women between the ages of 40 and 65, who were in various stages of transition, to examine the structure, blood flow, metabolism and function of the organ; two years later they did many of the same scans. They also mapped the brains of men in the same age range. “In women, not men, we found that the brain changes quite a lot,” says Mosconi. “The transition into menopause really leads to a complete reorganization.”
On average, women in the United States go through menopause around the age of 50 – defined as the first 12 consecutive months without a period; Once diagnosed, they are in postmenopause. But they can start having hormonal fluctuations at 40. (In some women, this happens in their 30s, and surgical removal of the ovaries results in immediate menopause, as does some cancer treatments.) These fluctuations cause irregular periods and potentially a variety of symptoms, including hot flashes, insomnia, mood swings, difficulty concentrating, and changes of sexual arousal. During this phase, known as perimenopause, which lasts an average of four years (but can last from several months to a decade), Mosconi and colleagues observed that their female subjects experience a loss of both gray matter (the brain cells that process information) as well as white matter (the fibers that connect these cells). However, after menopause this loss stopped and in some cases the brain volume increased, though not to its premenopausal size. The researchers also discovered corresponding shifts in the way the brain metabolizes energy, but these did not affect performance on memory tests, higher order processing, and language. This suggests that the female brain is “going through this process and recovering,” says Jill M. Goldstein, professor of psychiatry and medicine at Harvard Medical School and founder and executive director of the Innovation Center on Sex Differences in Medicine at the Massachusetts General Hospital. “It adapts to a new normal.”
