Risk Factors for Endometriosis: Menstrual and Life-Style Characteristics

Objective: To investigate possible risk factors for the development of endometriosis. Study Design: A case control study of 147 women with a new diagnosis of endometriosis, and 131 normal controls recruited from well women clinics. Controls were screened for the presence of symptoms of endometriosis. The setting was two tertiary referral centres for endometriosis and surrounding community clinics. Results: There was a significant positive association between double protection at menses and endometriosis (OR = 3.1), and a significant trend for cases to have shorter menstrual cycles. There was a greatly increased risk of endometriosis in those with an affected first-degree relative. Conclusions: Menstrual patterns producing a greater number of bleeding days are shown to be associated with a greater risk of endometriosis.