Unoperated ovarian endometriomas and responsiveness to hyperstimulation

Background: There is a growing consensus that ovarian reserve is reduced after surgical excision of ovarian endometriomas. However, it remains to be fully clarified whether this damage precedes or follows surgery. In order to further elucidate this aspect, we evaluated ovarian responsiveness to hyperstimulation in women selected for IVF with unilateral unoperated endometriomas. The main aim of this study was to compare the number of developing follicles in the affected ovary with that in the contralateral intact gonad as a control. Methods: Patients selected for IVF who were diagnosed with one or more monolateral endometriomas (diameter < 4 cm) and who did not undergo previous ovarian surgery were retrospectively identified. We compared the number of follicles (diameter >= 11 mm) and the number of co-dominant follicles (diameter > 15 mm) on the day of hCG administration in the affected and intact ovaries. Results: Among the 84 women selected, the median interquartile range (IQR) number of follicles >= 11 mm in the affected and intact ovaries was 5 (3-7) and 5 (3-8), respectively (P =0.36). The median (IQR) number of co-dominant follicles in the affected and intact ovaries was 3 (2-4) and 3 (2-5), respectively (P = 0.48). The number of co-dominant follicles was lower in the affected ovary in 36 cases (43%, 95% confidence interval: 32-53%). We also failed to identify any statistically significant difference between the two ovaries when evaluating data according to the number of cysts, their dimension, the dose of gonadotrophins used or the number of oocytes retrieved. Conclusions: In women selected for IVF, the presence of an endometrioma does not markedly affect responsiveness to hyperstimulation.