For many years we have known that regular menstrual cycles are a key vital sign for women. Not only can disordered menstrual cycle disrupt our sex life, our psyche, our gut health, and our fertility. Now we know this impacts brain health.
A new study published in the American Journal of Obstetrics and Gynecology has uncovered a compelling link between menstrual cycle patterns and cognitive performance in women. Researchers from Harvard T.H. Chan School of Public Health analyzed data from nearly 20,000 participants in the long-running Nurses’ Health Study II, focusing on menstrual cycle characteristics and cognitive assessments conducted between 2014 and 2022.
The key finding for Brain Health?
Women who reported irregular menstrual cycles between the ages of 29 and 46 scored lower on tests of learning and working memory compared to those with regular cycles. These differences were measured using the Cogstate Brief Battery, a validated tool for assessing cognitive function.
Interestingly, the cognitive performance of women with irregular cycles was equivalent to that of women 1.7 years older, suggesting a subtle but meaningful acceleration in cognitive aging. The study also noted that longer cycle lengths (over 25 days) during early adulthood (ages 18–22) were associated with similar declines.
These findings add to a growing body of research suggesting that menstrual cycle characteristics may reflect underlying hormonal and cardiovascular factors that influence brain health. As dementia continues to disproportionately affect women, understanding these early indicators could be key to prevention and intervention.
