Fig. 1

Flowchart of sample collection criteria. Among 631 cases, 7 cases were excluded because of the following complications: past medical history for the treatment of endometrial cancer (n = 4), cervical cancer diagnosed in early pregnancy (n = 1), and previous conization (n = 2). Of the remaining 624 cases, laparoscopically diagnosed endometriosis was present in 92 cases, which were classified as “endometriosis diagnosed by laparoscopy.” Twenty cases were excluded from this study because endometriosis was suspected but not diagnosed by laparoscopy. The other 512 cases were classified as “denied presence of endometriosis.” Among the 92 cases of “endometriosis diagnosed by laparoscopy,” 10 cases were classified as rASRM stage I or II, 31 cases were rASRM stage III, and 43 cases were rASRM stage IV. In eight cases, the rASRM stage was unavailable. ART: assisted reproductive technology, rASRM: revised American Society for Reproductive Medicine