Shafrir, Amy L, Palmor, Marissa C, Fourquet, Jessica et al. · American journal of reproductive immunology (New York, N.Y. : 1989) · 2021 · DOI
This study looked at whether young women and adolescents with endometriosis (a painful condition where tissue grows outside the uterus) are more likely to have immune system problems like allergies, asthma, or chronic fatigue. Researchers compared 551 women with surgically confirmed endometriosis to 652 women without it and found that those with endometriosis were significantly more likely to have chronic fatigue syndrome, fibromyalgia, or a history of mononucleosis. The more immune-related conditions a woman had, the higher her chances of also having endometriosis.
ME/CFS patients often experience comorbid conditions and immune dysfunction similar to endometriosis patients. This study's finding of a strong association between chronic fatigue syndrome/fibromyalgia and endometriosis suggests shared immune and inflammatory pathways that may inform understanding of ME/CFS pathophysiology. Clinically, it highlights the importance of screening for endometriosis in ME/CFS patients and vice versa, potentially improving diagnosis and management in overlapping populations.
This cross-sectional study cannot establish causation or temporal relationships—it does not show whether immune conditions cause endometriosis, endometriosis causes immune dysfunction, or both share a common underlying mechanism. The study relies on self-reported diagnosis of most conditions (not all surgically confirmed), which may introduce recall bias and differential misclassification. Associations observed do not prove biological mechanisms are responsible for the co-occurrence.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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