Exploring the Immediate Effects of an Online Self-Regulation Intervention on Pain, Affect, and Arousal in Women with Endometriosis: An Observational Study Protocol

Background Endometriosis is a chronic condition that affects millions of women worldwide, causing significant pain, emotional distress, and impaired quality of life. Despite advances in biomedical treatments, many patients continue to experience persistent symptoms due to the complex interplay between biopsychosocial factors, shaped by the lived experience of endometriosis and further exacerbated by socioeconomic adversities common in middle- and low-income countries. Self-regulation, the ability to modulate physiological and psychological responses, addresses core mechanisms underlying emotional challenges and pain, potentially benefiting interconnected difficulties. This study aims to evaluate the immediate effects of an online self-regulation intervention that integrates smooth whole-body movements, postural stillness, and deep breathing, explicitly guiding participants to train adaptive psychological attitudes such as present-centered awareness, nonreactivity, and acceptance through body exercises. Methods This observational study employs a within-subject, repeated-measures design to assess pre-to-post-session changes in pain intensity, affect, and arousal in women with symptomatic endometriosis. Assessments include self-reported measures of pain, affective states, and psychological attitudes before and after each session. Statistical analyses will use weighted fixed-effects regression models to estimate immediate changes, adjusting for session and clinical predictors. Mixed-effects models will explore individual variability, accounting for repeated measures within participants. Mediation analysis will examine whether nonreactivity and acceptance explain intervention effects on pain and affective outcomes. Additionally, qualitative analysis will be conducted using thematic content analysis of self-reflexive reports to capture participants' spontaneous narratives regarding their engagement with the intervention and its perceived impact beyond predefined quantitative outcomes. Data collection began in August 2024 at the Endometriosis Outpatient Clinic of Pedro Ernesto University Hospital. Discussion By investigating the acute effects of a structured online self-regulation intervention, this study aims to provide insights into non-pharmacological strategies for managing endometriosis-related pain and emotional distress. Understanding the short-term impact of the intervention will help refine its delivery and inform future research on long-term effects. Given the limited accessibility of specialized pain management resources, particularly in low- and middle-income settings, this study may contribute to the development of scalable, low-cost therapeutic approaches.