Impact of endometriosis on oocyte quality in women undergoing assisted reproduction.

Endometriosis is a chronic gynecological condition which can lead to infertility in women during reproductive age. Endometriosis influences the assisted reproductive technology (ART) outcomes by its impact on oocyte and embryo quality, oocyte numbers and subsequently the embryo numbers and endometrial receptivity. There has been clinical dilemma as to whether it is predominantly the oocyte, or the endometrium which affects the pregnancy outcomes in women with endometriosis. In this review we provide an overview of the effect of endometriosis on the oocyte molecular mechanism, the overall effect of endometriosis and its various stages as well as the effect of endometrioma on the oocyte quality in autologous study models. We have also provided a review of the donor oocyte models to study the effect of endometriosis on the endometrium. While initial small donor oocyte-based model studies suggested a possible major detrimental impact of oocyte quality on ART outcomes in women with endometriosis, the more recent studies have found minimal or no impact of oocyte quality on treatment outcomes. There is growing evidence to suggest an important contributory role of reduced oocyte yield on ART success in women with endometriosis. There is a need to explore whether oocyte yield and not the oocyte quality or endometrial receptivity, is the main reason for lower success in women with endometriosis following ART.