Myofascial Trigger Points and Central Sensitization Signs, but No Anxiety, Are Shown in Women with Dysmenorrhea: A Case-Control Study.

Background primary dysmenorrhea (PD) is considered to be a cyclic chronic pelvic pain, with its onset in menstrual periods, often accompanied by the presence of myofascial trigger points (MTP). Most MTPs in subjects with chronic pelvic pain are in the inferior part of the abdomen, in the rectus abdominis (RA) area. Central sensitization is closely related to chronic pain processes. Previous studies in women with chronic pelvic pain reported central sensitization signs in their subjects, such as lower pain pressure threshold (PPT). Several authors agree that PPT in the tibialis anterior (TA) muscle, seems to be a reliable reference for signs of central sensitization. Amongst the factors that seem to accompany central sensitization, the presence of anxiety needs to be considered. The aim of the present study was to analyze the existence of hyperalgesic MTPs in RA, central sensitization signs and anxiety in women with PD, in comparison with a control group (CG). Methods: This study was designed following an observational, cross-sectional, case-control model. A total sample of 80 subjects was recruited trough social webs and advertising (PD n = 39) (CG n = 41). PPT in RA and AT was assessed bilaterally through algometry, and anxiety was evaluated through the State−Trait Anxiety Inventory. Results: Statistically significant differences (p < 0.001) were shown for NRS average and maximum increase, as well as lower bilaterally RA and TA PPT in favor of PD group compared to CG. State or trait STAI did not show any statistically significant differences (p > 0.05) between groups. Conclusions: In this study, women with PD reported symptoms of myofascial pain syndrome and central sensitization, when compared with healthy controls, without any sign of anxiety acting as a confounder for pain sensitivity.