The prevalence of endometriosis in unexplained infertility: a systematic review

In 15-30% of the couples with infertility no abnormalities are found after the initial diagnostic work up. The aim of this study was to investigate the prevalence of endometriosis in patients with unexplained infertility undergoing a diagnostic laparoscopy in the current era of improved imaging and ART.A systematic search was conducted in PubMed, Embase and Cochrane Central, to identify all studies reporting on pelvic pathologies found by laparoscopy in couples diagnosed with unexplained infertility. Normal ovulatory cycles, a normal semen analysis and an infertility period of at least 12 months were the minimum requirements for a study population to be included.Endometriosis was diagnosed in 44% and most lesions were classified as minimal or mild (74%). The prevalence of tubal factors and adhesions was respectively 20% and 16%. The detection rate of pelvic abnormalities was higher in women who underwent prior fertility treatment (75%) compared to women without prior treatment (53%).Despite the significant improvements in imaging for the diagnosis of endometriosis and tubal factors over the last decades, the prevalence of endometriosis and tubal abnormalities remains high in patients with unexplained infertility. The high prevalence of endometriosis in this population is important for decision making in patients who also suffer from pain symptoms suggestive of endometriosis.