Longitudinal co-activation pattern analysis of menstrual cycle-related brain dynamics in primary dysmenorrhea

Primary dysmenorrhea (PDM) is a chronic pelvic pain condition characterized by recurrent painful phases. While abnormal prostaglandin activity is central to its pain mechanism, and previous studies link PDM to central nervous system alterations associated with prostaglandin F2αlevels and pain intensity, the dynamic evolution of brain networks across the menstrual cycle remains unknown. This study employed the co-activation pattern analysis to investigate dynamic brain network characteristics across the menstrual, periovulatory, and luteal phases. Correlation analyses were performed between CAP metrics, pain scores, and PGF2α levels. Our results revealed that dynamic alterations of brain networks in patients with PDM exhibited trending changes throughout the menstrual cycle. Notably, the default mode network, salience network, sensorimotor network, and central executive network demonstrated significant periodic changes, which correlated with fluctuations in pain and PGF2α levels. This longitudinal study elucidates the dynamic neural mechanisms of patients with PDM, offering insights for early intervention strategies.