BACKGROUND: Laparoscopic surgery is the gold standard treatment for ovarian endometriomas. The aim of this study was to evaluate the impact of two different laparoscopic methods on sonographic indicators of ovarian reserve in the treated ovary.METHODS: In this prospective randomized clinical trial, 20 patients with endometriomas were randomly assigned to undergo either laparoscopic cystectomy (Group 1) or the 'three-stage procedure' (Group 2). All patients underwent ultrasound examination preoperatively and 6 months after laparoscopy. Another ultrasound examination was performed 12 months after intervention in order to detect any recurrence. We investigated the alterations in the residual ovarian volume, ovarian vascular supply and antral follicle count (AFC) on the ovary with the endometriotic cyst by transvaginal color Doppler ultrasonography.RESULTS: The residual ovarian volume and the lowest pulsatility and resistance indexes were found to be similar between the two groups before and 6 months after laparoscopic intervention. The AFC of the operated ovary was increased significantly (P = 0.002) in Group 2 compared with Group 1 after 6 months. One year after laparoscopy, two recurrences of endometriomas were detected in Group 2, although none were detected in Group 1 (P = 0.47).CONCLUSIONS: Ovarian volumes and vascularization were comparable among the two laparoscopic methods. On the contrary, functional ovarian tissue as determined by AFC was higher after the 'three-stage' procedure.