While no strong studies have been performed on endometriosis and chronic fatigue syndrome (also called myalgic encephalomyelitis)(CFS/ME), CFS/ME has been found with some frequency in those with endometriosis. This doesn’t mean that one causes the other. Rather it indicates that they can often be found present together, like we see with migraines and endometriosis. It is good to consider that there may be some overlapping symptoms and that more than one etiology may be present.
Boneva et al. (2019) reports that:
“Chronic fatigue syndrome (CFS), also referred to as myalgic encephalomyelitis (ME) or ME/CFS, is a serious chronic condition characterized by significant impairment in activity levels due to profound fatigue, worsening symptoms after seemingly minimal physical, or mental exertion, sleep problems, as well as difficulties with memory and concentration or orthostatic intolerance (1). Patients with ME/CFS also frequently experience chronic joint and muscle pain. Conditions with chronic pain as a major symptom, such as ME/CFS, endometriosis (EM), fibromyalgia, interstitial cystitis/bladder pain, irritable bowel syndrome, temporomandibular joint syndrome, and chronic migraines, have been termed chronic overlapping pain conditions. There is evidence that persons with one of these conditions are more likely to have another one as a co-morbidity…. We found more than a third of women with CFS reported endometriosis as a comorbid condition.”(Boneva et al., 2019)
This comorbidity, as well as other chronic pain conditions (interstitial cystitis, irritable bowel syndrome, chronic headaches, chronic low back pain, vulvodynia, fibromyalgia, temporomandibular joint disease, and chronic fatigue syndrome) has been noted in adolescents as well (Smorgick et al., 2013).
Boneva, R. S., Lin, J. M. S., Wieser, F., Nater, U. M., Ditzen, B., Taylor, R. N., & Unger, E. R. (2019). Endometriosis as a comorbid condition in chronic fatigue syndrome (CFS): secondary analysis of data from a CFS case-control study. Frontiers in pediatrics, 7, 195. Retrieved from https://doi.org/10.3389/fped.2019.00195
Smorgick, N., Marsh, C. A., As-Sanie, S., Smith, Y. R., & Quint, E. H. (2013). Prevalence of pain syndromes, mood conditions, and asthma in adolescents and young women with endometriosis. Journal of pediatric and adolescent gynecology, 26(3), 171-175. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S1083318813000028