E2 ModeratePreliminaryPEM unclearCross-SectionalPeer-reviewedMachine draft
Endometriosis as a Comorbid Condition in Chronic Fatigue Syndrome (CFS): Secondary Analysis of Data From a CFS Case-Control Study.
Boneva, Roumiana S, Lin, Jin-Mann S, Wieser, Friedrich et al. · Frontiers in pediatrics · 2019 · DOI
Quick Summary
This study looked at 36 women with ME/CFS to see how many also had endometriosis (a painful condition where tissue grows outside the uterus) and whether it affected their health differently. More than one-third of the women with ME/CFS had endometriosis, and those women reported more ME/CFS symptoms, pelvic pain, and earlier menopause than women with ME/CFS alone. However, endometriosis did not seem to worsen their overall fatigue or functioning.
Why It Matters
Many women with ME/CFS have endometriosis, yet this comorbidity is understudied. This research quantifies the overlap and identifies specific symptom burdens associated with having both conditions, which can improve clinical recognition and patient counseling. Understanding which biological pathways are—or are not—shared between these conditions could inform targeted treatments.
Observed Findings
- 36.1% of women with ME/CFS reported having endometriosis as a comorbid condition.
- Women with both conditions reported more ME/CFS symptoms (6.8 vs. 5.5, p=0.02) than those with ME/CFS alone.
- CFS+EM group had significantly earlier menopause onset (36.4 vs. 47.0 years, p=0.03) and higher obstructive apnea episodes per hour (20.3 vs. 4.4, p=0.05).
- Women with CFS+EM were 9 times more likely to report chronic pelvic pain and 10.3 times more likely to have had hysterectomy.
- Inflammatory markers, fatigue severity, and functioning did not differ significantly between groups.
Inferred Conclusions
- Endometriosis is a common comorbidity in women with ME/CFS, occurring in more than one-third of the sample.
- Endometriosis in ME/CFS patients is associated with increased symptom burden, pelvic pain, and earlier menopause but does not appear to exacerbate the core immunological or inflammatory features of ME/CFS.
- The mechanisms linking endometriosis and ME/CFS may be distinct from shared inflammatory or immune dysregulation pathways.
Remaining Questions
- Does endometriosis increase the risk of developing ME/CFS, or are these conditions coincidentally comorbid in susceptible individuals?
- Why does endometriosis correlate with more CFS symptoms but not with elevated inflammatory markers or altered cortisol levels?
What This Study Does Not Prove
This study does not establish whether endometriosis causes or contributes to ME/CFS development, nor whether treating endometriosis would improve ME/CFS outcomes. The small sample size (36 women, mean age ~51 years) and cross-sectional design mean findings may not generalize to younger women or different populations. Association does not imply causation, and unmeasured confounders could explain the observed patterns.
Tags
Symptom:Unrefreshing SleepPainFatigue
Biomarker:Blood Biomarker
Method Flag:Weak Case DefinitionSmall SampleExploratory Only
Metadata
- DOI
- 10.3389/fped.2019.00195
- PMID
- 31179251
- Review status
- Machine draft
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 8 April 2026
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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