Researchers conducted periodic memory tests on 803 menopausal women over two years and found to their surprise that their memories were just fine. In fact, the women's scores improved slightly over time; the researchers were expecting a decline.
The researchers said that if menopausal women are forgetful sometimes, it is probably not because of any harmful hormonal changes in the brain, but because they are busy, distracted and stressed-out dealing with the ordinary pressures of midlife.
"We are not saying that the forgetfulness is all in their heads," said lead researcher Peter M. Meyer, a biostatistician at Rush University Medical Center in Chicago. "The question we were trying to answer was: Is this forgetfulness reflective of something bigger, below the surface," such as the onset of mental decline?
Many women complain that they become more forgetful after menopause, and some doctors have come to believe that the hormonal changes brought on by menopause are the reason.
Naturally occurring estrogen is thought to help keep brain cells healthy, but it drops during menopause. In fact, the hormone supplement industry was built partly on the premise that estrogen pills could keep women's minds sharp — an idea that has recently been challenged.
The new study appears in Tuesday's issue of the journal Neurology.
"It may be that the brain does not need the hormones as much as we think," Russel Thompson of the South Texas Veterans Health Care System wrote in an accompanying commentary.
Other research has suggested that midlife forgetfulness might be due to stresses such as children becoming teenagers and parents dying. Meyer said those stresses, rather than true mental decline, could account for what some women describe as memory loss.
Dr. Sam Gandy, a neurologist at Thomas Jefferson University, said the study is "reassuring in the short term" but does not settle whether the hormonal changes in menopause might hasten mental decline and lead to Alzheimer's disease later on.
The brain processes involved in Alzheimer's typically begin at least 10 years before symptoms occur, so the Chicago women would need to be followed longer to see if the early results hold up, said Gandy, a scientific adviser to the Alzheimer's Association.
The study involved white and black women from Chicago ages 42 to 52, most of whom had not yet reached complete menopause, meaning they still menstruated occasionally, though their bodies were producing dwindling levels of estrogen and progestin hormones.
The participants were not taking hormone supplements, which were recently linked to an increased risk of dementia in older women.
The women were given two standard memory tests every year and were followed for an average of a little more than two years.
On one test asking them to reverse a string of numbers from memory, scores improved by an average of about 3 percent.
On the other test, women had 90 seconds to read rows of symbols and recall numbers previously assigned to each symbol. Those scores improved by an average of about 8 percent for premenopausal women. They declined slightly for postmenopausal women, but no more than would be expected with normal aging, Meyer said.
The findings were a surprise to Barbara Jester, 57, a New York City writer who said she and her friends sometimes have trouble remembering common nouns.
With a full-time job at New York University and a grown son who recently moved back home, Jester said she would be reassured if the findings meant her lapses are "just a blip" and not due to some underlying mental decline.
Diane Dobry, a 46-year-old New Yorker whose grandmother has dementia, said having two children in college and dealing with multiple tasks at work might help explain her own memory lapses. Dobry, communications director for Teachers College Columbia University, said she sometimes tells her children: "I have to try to think for everybody, and it's spreading thin."
But Dobry said she is skeptical of the findings "because you always hear in a year or two, a study that says the complete opposite."
For now, she said she will stick with "taking classes and trying to prove I can learn new things" to help keep her brain in shape.