Risk factors for pelvic endometriosis in women with pelvic pain or infertility

Objective: The objective of the study was to analyse the relationship between selected characteristics and risk of pelvic endometriosis. Study design: Eligible for the study were 817 women with primary or secondary infertility or pelvic pain requiring laparoscopy. Of these, 393 were included for infertility and 424 for pelvic pain. Results: A total of 345 (42.2%) had a diagnosis of endometriosis and 472 did not have the disease. Multiparous women had endomertriosos less frequently than nulliparous, the estimated odds ratios (OR) were respectively 0.9 (95% confidence interval, CI, 0.5–1.6) and 0.4 (95% CI 0.2–0.7) in women reporting one and two or more births. In comparison with women reporting no spontaneous abortion, the estimated OR was 0.3 (95% CI 0.2–0.5) in those who reported ≥1 miscarriage. In comparison with women reporting menstrual cycles lasting ≥25 days subjects with totally irregular menstrual cycles had a reduced risk of endometriosis (OR 0.6, 95% CI 0.3–0.9). No significant association emerged between smoking, age at menarche and risk of endometriosis. Conclusions: this study confirms, with a different methodological approach to previously published studies, that multiparity, a history of abortion and lifelong irregular menstrual pattern decrease the risk of endometriosis in women with pelvic pain and infertility.