Papers of the Week

Dysmenorrhea, or recurrent menstrual pain, is a highly prevalent pain condition among otherwise healthy women. However, the progression of dysmenorrhea over time and the influence of the menstrual cycle phases need to be better understood. While the location and distribution of pain have been used to assess pain mechanisms in other conditions, it is unexplored in dysmenorrhea. Thirty otherwise healthy women with severe dysmenorrhea and 30 healthy control women (HC) were recruited into three subgroups (n=10) according to the length of their menstrual history (<5, 5-15, or >15 years since menarche). The intensity and distribution of menstrual pain were recorded. Pressure pain thresholds (PPTs) at abdominal, hip, and arm sites, pressure-induced pain distribution, temporal summation of pain, and pain intensity after pressure cessation over the gluteus medius were assessed at 3 menstrual cycle phases. Compared with HC, women with dysmenorrhea showed lower PPTs in every site and menstrual cycle phase (P<0.05), enlarged pressure-induced pain areas during menstruations (P<0.01), and increased temporal summation and pain intensity after pressure cessation in the overall menstrual cycle (P<0.05). Additionally, these manifestations were enhanced during the menstrual and premenstrual phases compared to ovulation in women with dysmenorrhea (P<0.01). Women with long-term dysmenorrhea demonstrated enlarged pressure-induced pain distribution, enlarged menstrual pain areas, and more days with severe menstrual pain compared to the short-term dysmenorrhea subgroup (P<0.01). Pressure-induced and menstrual pain distributions were strongly correlated (P<0.001). These findings suggest that severe dysmenorrhea is a progressive condition underscored by facilitated central pain mechanisms associated with pain recurrence and exacerbation. PERSPECTIVE: Enlarged pressure-induced pain areas occur in dysmenorrhea, associated with the length of the condition and the distribution of menstrual pain. Generalised hyperalgesia is present throughout the entire menstrual cycle and intensifies during premenstrual and menstrual phases.