Pelvic floor myofascial pain (PFMP) is part of pelvic floor myofascial pain syndrome, pelvic floor myalgia, pelvic floor tension myalgia, and other similar conditions typically characterized by the presence of trigger points or tender areas along the pelvic floor muscles, increased tone, with local and referred pain. PFMP is increasingly recognized in association with lower urinary tract symptoms (LUTS), such as urinary urgency incontinence, overactive bladder, and interstitial cystitis/bladder pain syndrome (IC/BPS) [1]. Prevalence estimates of PFMP in clinical settings are reported as much as 85-87% in patients with chronic pelvic pain, IC/BPS, and other pelvic floor disorders, to as little as 17% in pain-free controls. Prevalence estimates for PFMP in the general population are not known. The RISE FOR HEALTH study is a regionally-representative population-based prospective cohort study of 2968 women recruited from 9 geographic areas in the United States and conducted by the Prevention for Lower Urinary Tract Symptoms (PLUS) Research Consortium. The RISE study is designed to identify factors that promote bladder health and/or prevent LUTS in adult women and included an in-person assessment of a subset of the study population. The in-person assessment provided an ideal opportunity to obtain population-based estimates of the prevalence of PFMP on palpation. The aim of this study is to describe the prevalence of PFMP on muscle palpation in this population of adult women; and examine factors associated with PFMP.

This was a planned subanalysis of a subset of RISE participants (n=520) who enrolled in an in-person assessment designed to capture a number of physical and biological data points deemed potential factors associated with bladder health as previously described [2]. Pelvic floor muscle assessments included presence of prolapse, pelvic floor muscle strength, levator ani muscle attachment integrity (tear) and PFMP with palpation as previously described [3]. Specifically, presence of pain with palpation in the obturator internus (OI) and levator ani (LA) was assessed bilaterally and reported using a numeric score of 0-10 for each muscle where 0=No pain, 1-3=Mild pain, 4-6=Moderate pain, and 7-10=Severe pain; a discrete number was reported for each muscle assessment. Proportional odds logistic regression was used to examine associations between demographic and clinical characteristics and OI and LA PFMP.

The mean age of the 502 participants was 50.4±17.5 years, 98% identified cis-gendered female.  The majority identified as non-Hispanic White (72%), 62% were overweight or obese, and slightly over half were vaginally parous (53%). Over two-thirds had college or graduate-level education, almost two-thirds were employed, 24% were retired, and 84% were insured. Less than half (45%) reported discussing bladder-related concerns with a healthcare provider and only 3% reported having a diagnosis of IC/BPS. Table 1 shows the PFMP with palpation scores from the standardized assessment. Over half reported no pain with palpation in the OI and LA muscles, approximately 25% had mild-range pain in the OI and LA muscle groups while 9-13% reported moderate-to-severe pain in the OI muscles and 8-9% reported moderate-to-severe pain in the LA muscles.  Overweight body mass index (BMI) t was the only factor associated with an increased odds of having worsening pelvic floor myofascial pain with palpation (Table 2), whereas age (26-44, 45-64, 65+ compared to <25), education level (compared to graduate), and vaginal parity (compared to nulliparity) were not associated with OI or LA myofascial pain with palpation.

This study is notable as it provides estimates of the distribution of PFMP with palpation in a non-clinical adult female population. In this subset of community dwelling women, approximately 10% of women had moderate-to-severe range PFMP with palpation of OI and/or LA muscles on examination. While over half had no PFMP in either the OI or LA muscles bilaterally, approximately 25% of women had mild-range pain. Combining pain groupings would yield estimates of “any PFMP” ranging from 38-44% in the OI muscles and 37-39% in the LA muscles. Interestingly, the only risk factor we found to be associated with PFMP with palpation was being overweight, which may increase load and strain on the muscles leading to injury and pain. Reasons why obesity was not associated with this are unclear.

This study provides estimates of PFMP with palpation in US adult community-dwelling women. While the majority of women had no PFMP in either the OI or LA muscles, a significant proportion had some degree of PFMP and being overweight, but not obese, was associated with higher prevalence of PFMP. Future work will determine if there is an association between the presence or absence of PFMP with palpation and bladder health or LUTS. These estimates can be used for designing studies for PFMP with palpation where recruitment from a non-clinical setting is desired.

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