New Risks for Women with Endometriosis

Endometriosis affects as many as 6% of the general population. While some women with endometriosis remain asymptomatic, many women experience dysmenorrhea, dyspareunia, non-cyclical pelvic pain, and subfertility. Now, new research indicates that patients with endometriosis are also more likely to develop inflammatory bowel disease.

Dr Tine Jess, senior researcher in the department of epidemiology research at the Statens Serum Institute in Copenhagen, Denmark, and colleagues, analyzed the national Danish registers to assess the risk of Crohn’s disease and ulcerative colitis among women who had endometriosis. The researchers identified 37,661 women who had been hospitalized for endometriosis over a 30 year period. The selected women were then followed until diagnosis of inflammatory bowel disease or data was no longer available (ie, due to death, emigration, or other disappearance). To determine relative risk of developing either Crohn’s disease or ulcerative colitis following a diagnosis of endometriosis, the researchers used observed versus expected numbers to calculate standardized incidence ratios.

Overall, Jess and colleagues found an increased risk of developing inflammatory bowel disease for women who had endometriosis as demonstrated by a standardized incidence ratio of 1.5. This amounts to a 50% increase in the risk for inflammatory bowel disease among this patient population. The researchers found standardized incidence ratios of 1.5 and 1.6 for ulcerative colitis and Crohn’s disease, respectively. When Jess and colleagues limited analysis to those women whose diagnoses of endometriosis were verified via surgery, the association between endometriosis and ulcerative colitis and Crohn’s disease increased, with standardized incidence ratios climbing to 1.8 and 1.7, respectively. On average, women with endometriosis developed inflammatory disease about 10 years after their endometriosis diagnosis.

“The risk of IBD [inflammatory bowel disease] in women with endometriosis was increased even in the long term, hence suggesting a genuine association between the diseases,” Jess and colleagues concluded, adding, “[This] may either reflect common immunological features or an impact of endometriosis treatment with oral contraceptives on risk of IBD.”

Because of the possible link between treatment of endometriosis and the risk of developing inflammatory bowel disease, the researchers agreed that further study is warranted. Moreover, since these diseases have an apparent overlap, careful diagnostic work-up should be completed when patients present with persisting abdominal or gynecological symptoms.