Fatigue is a common but underestimated symptom of endometriosis, according to findings from an international study of over 1,100 women. The findings are published in Human Reproduction.
The study found that the prevalence of fatigue was more than doubled in women diagnosed with endometriosis compared to those who were unaffected by the condition, and it remained significant after the results were adjusted for other factors that might play a role in fatigue, such as pain, insomnia, occupational stress, depression, body mass index, and motherhood.
“These findings suggest that endometriosis has an effect on fatigue that is independent of other factors and that cannot be attributed to symptoms of the disease,” says Brigitte Leeners, deputy head of the Department of Reproductive Endocrinology at the University Hospital Zurich, Switzerland, who led the research, in a release.
“Although chronic fatigue is known to be one of the most debilitating symptoms of endometriosis, it is not widely discussed and few large studies have investigated it. We believe that in order to improve the quality of life for women with this condition, investigating and addressing fatigue should become a routine part of medical care, and doctors should investigate and address this problem when they are discussing with their patients the best ways to manage and treat the disease. It would also help these women if steps were taken to reduce insomnia, pain, depression, and occupational stress.”
Endometriosis is a condition in which the endometrial cells that form the inside of the womb also grow in other areas of the pelvic region, such as the ovaries and the abdominal cavity. The main symptoms are pain and infertility, although not all women will have these symptoms. It is not known what causes it, but it is a common gynecological disease with a global prevalence of between 6% to 10%. It can be treated with drugs, such as anti-inflammatories and hormone therapy, and with surgery.
The researchers recruited 1,120 women, 560 with endometriosis matched with 560 without it, from hospitals and private practices in Switzerland, Germany, and Austria between 2010 and 2016. The women completed a questionnaire that asked about various factors relating to quality of life and endometriosis, as well as medical and family histories, lifestyle, and mental disorders. Fatigue and insomnia were categorized into five different levels ranging from 1 (never) to 5 (very often).
They found that 50.7% of women diagnosed with endometriosis suffered from frequent fatigue compared to 22.4% of women without the condition. Fatigue with endometriosis was also associated with a more than seven-fold increase in insomnia, a four-fold increase in depression, a two-fold increase in pain, and a nearly 1.5-fold increase in occupational stress. Age, time since first diagnosis, and the stage of the disease were not linked to fatigue.
The researchers say that a possible reason why endometriosis could cause fatigue, independently of the other factors, is that the endometrial lesions may be causing inflammation that activates the immune system. Proteins called cytokines that are involved in cell signalling when the immune system is activated have been shown to play a role in fatigue symptoms. Chronic exposure to high stress can result in adrenal fatigue, and this could be an additional possible explanation.
Limitations of the study include the fact that answers to the questionnaires are subjective and at risk of bias from failure to accurately recall experiences in the past six months, and the fact that the researchers did not have information on the exact medication taken during the relevant period.