Does endometriosis affect oocyte quality in in vitro fertilization and intracytoplasmic sperm injection cycles compared to oocyte were endometrioses has been excluded by laparoscopy?

Introduction:

Controversial studies have suggested that impaired oocyte quality may be involved in the pathogenesis of endometriosis-related infertility. Up to now, no study has evaluated the effect of oocyte quality with a zygote score from infertile women with endometriosis in comparison to women excluded endometriosis.

Materials and methods:

413 zygotes from 39 women with histologically proven endometriosis were examined. 22 of them had mild and 17 severe endometrioses according to rASRM. 13 had additional endometrioma. Controls were 309 zygotes from 37 women, where endometriosis has been excluded by laparoscopy. The morphology of the zygotes was rated using an inverted microscope and the scoring system regarding Zollner et al. (2002), where a low score means a good quality. This established PN-scoring system allows selection of zygotes with favorable developmental potential for further embryo culture.

Results:

No significant differences in the number of retrieved oocytes were observed (8.4 ± 5.0 vs. 10.4 ± 9.9). Patients with endometriosis had significantly higher mean zygote scores (18.1 ± 2.3 vs. 16.8 ± 1.8, p = 0,002) with often strong cytoplasmic vacuolization and no halo effect. Comparison between severe endometriosis and mild endometriosis revealed a significantly lower rate of mean numbers of mature oocytes in severe endometriosis (12.9 ± 11.7 vs. 6.5 ± 5.4, p = 0,019). Ovarian responsiveness and oocyte quality did not significantly differ between patients with endometrioma and patients without.

Conclusion:

Endometriosis patients present a lower ovarian responsiveness and quality of oocytes. Further studies are necessary to understand mechanisms of endometriosis-associated infertility to improve the chances of a successful IVF/ICSI.