New Study Offers Possible Explanation for ‘Mommy Brain’ During Pregnancy
Researchers found that sustained high estrogen can disrupt a memory circuit, and 70 women in the study showed modest memory changes.
- Researchers published a study on August 25, 2026, in the journal "Science Bulletin" identifying a biological link between high estrogen levels during pregnancy and temporary memory impairment.
- Using mice to mimic pregnancy hormone levels, researchers found high estrogen activates GABA-releasing neurons in the lateral hypothalamus, which project to the hippocampus and disrupt memory-related activity.
- Dr. Zheng Sun, an associate professor of medicine at Baylor College of Medicine, assessed 70 women and found pregnant participants performed worse on simple memory tests, confirming "momnesia" is real.
- Research published in "Nature Communications" found gray-matter volume decreased by up to 4.9% during pregnancy across 94% of the brain's volume, though partial recovery occurred postpartum.
- Sun cautioned against overinterpreting results, noting human effects are modest and short-lived, while hoping the work encourages greater attention to unique physiological changes in women's health.
21 Articles
21 Articles
'Momnesia' pregnancy forgetfulness linked to brain circuit disruption, study finds
Scientists have now found a possible explanation for ‘mommy brain’. High oestrogen increased the activity of hypothalamus neurons, which in turn suppressed activity in the hippocampus and impaired memory, they found
Forgetting why you entered a room, losing your house keys, or having difficulty remembering someone's name are situations reported by many women during pregnancy. Known informally as "mononesia" or "pregnant brain", the phenomenon may have a biological explanation. A new study has identified, in mice, a brain circuit that suffers changes in view of the high and sustained levels of estrogen characteristic of pregnancy.
The window of entry into a room and then forget the reason why it's reached, or put the keys in an unusual place, or suddenly lose the thread of conversation... attitudes that many women tell during pregnancy, sometimes referred to as "pregnancy brain."
It is sometimes called “momnesia”, “mommy brain”, “pregnancy brain” or “baby brain” - terms that describe forgetfulness, mental blur, and changes in
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