The Brain Shrinks as We Age and During Major Transitions. But Surprisingly, It Seems to Take a Break From Rewiring During Menopause

Puberty, pregnancy and menopause are the three major hormonal transitions for the female brain. Researchers already knew that during the first two, the organ fine-tunes itself in response to hormonal shifts, but they haven’t been sure about the third

Sara Hashemi | Daily Correspondent

September 21, 2026 2:51 p.m.

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The brain goes through substantial changes during puberty and pregnancy, both marked by major hormonal shifts. Yet during the third female hormonal transition period—menopause—the organ seems to hit pause on rewiring.

That’s according to a new study that examined scans of 1,095 female brains across three life stages: first menstrual cycle, pregnancy and menopause. The work, published in the journal Nature Communications on September 8, hints that the loss of gray matter volume typically tied to hormone changes doesn’t happen during menopause. What’s more, aging-related brain shrinkage also temporarily halts during this time.

The findings address an important gap in our understanding of the female brain. Although women make up half the world’s population, only 2 to 6 percent of neuroscience studies are conducted with exclusively female samples, and fewer than 5 percent of studies treat sex as a factor in analysis, the researchers write in the paper.

Moreover, “no one had looked at the changes in the whole brain matter in this menopause transition before,” said study co-author Sophie van ’t Hof, a cognitive neuroscientist at Amsterdam University Medical Centre, during a press conference, reports Claire Cameron at Scientific American.

Scientists already know from past research that during puberty and pregnancy, the volume of gray matter dramatically shrinks. Gray matter largely consists of nerve cell bodies that help process information, and much of it is in the brain’s wrinkly outer layer, or cerebral cortex. Shrinkage during these transitional periods likely happens because the organ rewires its neural networks as it prepares for a new stage of life.

At the same time, the brain also gradually loses gray matter as we age. “People often think the brain is just done when you’re an adult, but it changes throughout life,” van ’t Hof tells Science News’ Bethany Brookshire. “We see these small gray matter reductions throughout the whole life.”

In the study, van ’t Hof and colleagues examined data from the U.K. Biobank and several studies conducted at Leiden University in the Netherlands. They analyzed brains of different participants at two time points: before and after their first period, before and after their first or second pregnancy, or before and after menopause. They also included control groups, such as adolescents stably pre- or post-first menstrual cycle and adults pre- or post-menopause.

The onset of puberty was linked with a monthly decline of 0.13 percent of gray matter, while pregnancy was associated with a monthly reduction of 0.12 percent, the team found, aligning with previous findings. These alterations weren’t seen in the age-matched controls.

But something unusual happened to brains during menopause, defined at the one-year mark since a person’s last period. They didn’t go through changes typically associated with hormonal shifts, and age-related decreases in gray matter stopped, too. The exact timing of the rewiring pause varied between participants, van ’t Hof tells Live Science’s Theresa Sullivan Barger, but they were consistent overall.

“This study provides the first direct longitudinal comparison of brain structural changes across all three major female hormonal transitions,” Magdalena Martínez-García, a neuroscientist at the University of California, Santa Barbara who was not involved in the work, tells the outlet. “I really appreciate the effort that went into finding and curating such an impressive longitudinal dataset of the female brain.”

Still, the work has a few limitations. The participants self-reported their stages of menopause and did not use diagnostic tests. The pre- and post-menopause data represent only two time points per person following a long period called perimenopause, where “the dialogue between the ovary and the brain is already readjusting to the progressive decline of the ovarian reserve,” Susana Carmona, a neuroscientist at Instituto de Investigación Sanitaria Gregorio Marañón in Spain who wasn’t involved in the study, tells Science News. “Capturing such a long, gradual transition with a single self-reported item is difficult.”

Nevertheless, the findings open the door for more research on how hormonal changes impact the brain around menopause. For instance, many people experience cognitive issues, like brain fog, during this time, but the researchers aren’t sure if that’s because of something going on in the brain or hormone fluctuations and sleep troubles, reports Live Science.

“The exact implications are very difficult at this stage,” van ’t Hof said at the press conference.

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.