Association between dysmenorrhea and chronic pain: A systematic review and meta-analysis of population-based studies

Abstract OBJECTIVE To synthesize the epidemiological findings for the associations between dysmenorrhea, including primary dysmenorrhea and endometriosis-associated dysmenorrhea, and any chronic pain conditions, including chronic pelvic pain, and chronic non-pelvic pain. DATA SOURCES PubMed, Embase, and CINAHL from inception to December 2019. STUDY ELIGIBILITY CRITERIA Observational population-based studies in which the relationship between dysmenorrhea and the presence or severity of chronic pain was examined. STUDY APPRAISAL AND SYNTHESIS METHODS Each study was double-coded and evaluated for bias based on the modified Newcastle and Ottawa Scale. Random-effect meta-analyses were conducted to quantify the associations between dysmenorrhea and the presence of chronic pelvic and non-pelvic pain. RESULTS Out of 9,452 records, 32 studies were included, with 14 reporting associations between dysmenorrhea and chronic pelvic pain, and 20 for dysmenorrhea and chronic non-pelvic pain. Primary dysmenorrhea and endometriosis-associated dysmenorrhea were examined in 7 studies, respectively. Over 30% of the studies were categorized as poor quality, 56% as moderate, and 12.5% as high. Dysmenorrhea was positively associated with both the presence and severity of chronic pelvic and non-pelvic pain conditions. Based on 6,689 women from 8 studies, those with chronic pelvic pain had 2.43 (95% confidence interval = 1.98, 2.99, I2 = 42%) times the odds of having dysmenorrhea compared to those without. Based on 3,750 women from 11 studies, those with chronic non-pelvic pain had 2.62 (95% confidence interval = 1.84, 3.72, I2 = 72%) times the odds of having dysmenorrhea compared to those without. Overall, dysmenorrhea was associated with 2.50 (95% confidence interval = 2.02, 3.10) times the odds of chronic pain, which did not differ by chronic pelvic vs chronic non-pelvic pain, community vs clinical populations, or different geographical regions. CONCLUSIONS Dysmenorrhea may be a general risk factor for chronic pain, although whether primary dysmenorrhea increases the risk for chronic pain is unclear. Given that adolescence is a sensitive period for neurodevelopment, elucidating the role of primary dysmenorrhea in pain chronicity in future longitudinal studies is important for preventing both chronic pelvic and non-pelvic pain.