Taiwanese researchers have found that painful menstruation changes the structure of the gray matter of the brain, reports EurekAlert!. Scientists from the National Yangming University in Taipei conducted a study among 32 patients with primary dysmenorrhea (painful menstruation in which the pain syndrome is not due to any disease). The obtained results were compared with those of the same number of healthy women, without complaints of pain and discomfort during their monthly cycle. All the participants in the study were subjected to a nuclear magnetic resonance examination, on the basis of which the scientists compiled maps and determined the size of the gray matter in each lobe of the brain. In the group suffering from dysmenorrhea, the studies were conducted during a period when the women had no complaints. Analysis of the data showed that in women with dysmenorrhea, the structure of the gray matter of the brain was changed. Areas in the brain responsible for pain transmission, processing sensory information and regulation of emotional responses were reduced in size, while those involved in pain modulation and regulation of the endocrine system were enlarged. The results show that painful menstruation causes long-term changes in the structure of the gray matter of the brain, which are preserved even in the absence of pain syndrome, explains the leader of the study Dr. Jen-Chuen Hsieh. To determine whether these brain changes are reversible in the long term, the scientists plan to conduct larger studies involving the study of hormonal changes at different times of the menstrual cycle.