Beyond nociception: rethinking pain in ovarian endometriosis a pilot study

Endometriosis affects 1 in 10 women, is the most common cause of chronic pelvic pain, classically known for its nociceptive pain mechanisms. Medical therapies have limited efficacy, prevent pregnancy, and can be poorly tolerated in over 30% of cases. Meanwhile, surgical management can be associated with up to 37% of pain persistence, and over 45% undergo repeat surgery within five years.

To characterize differing pain profiles between women with ovarian endometriosis and those with other benign ovarian cysts.

Prospective observational cross-sectional clinical study between surgical ovarian endometriosis and control individuals. The primary outcome was to detect differences in the presence of nociplastic pain among the two groups using the Fibromyalgia (FM) Survey Score.

33 participants were approached from July 2024 to October 2024. Twelve participants with ovarian endometriosis and eight control participants with non-endometriosis ovarian cysts were enrolled. There was a statistically significant difference in the prevalence of elevated FM Survey score between the endometriosis group and controls (41.7% vs. 0%, p = 0.045). Further significant differences were identified in total FM Survey scores, Brief Pain Inventory pain severity, visual analog pain scores for dysmenorrhea, chronic pelvic pain, dyschezia, dysuria, dyspareunia, and evidence of adenomyosis.

Ovarian endometriosis, despite its well-known inflammatory pain characteristics, is associated with elevated FM survey scores, which may suggest nociplastic centrally mediated pain mechanisms.