Endometrioma, the follicular fluid inflammatory network and its association with oocyte and embryo characteristics

Research question: What is the association between endometrioma-affected ovaries, their follicular fluid inflammatory microenvironment, and ovary-specific oocyte and embryo yield and quality? Design: Exposure-matched prospective cohort study conducted at a university-affiliated infertility clinic. Thirty-four women presenting for oocyte retrieval were enrolled between 2012 and 2013: women with unilateral endometrioma and no other observed peritoneal or deep lesions (n = 10) and women with no signs or symptoms of endometriosis (n = 24). Follicular fluid was aspirated at the time of oocyte retrieval. Samples from each ovary were analysed using a 27-plex immunoassay panel. The associations were evaluated by ovary-specific endometrioma exposure status (affected, unaffected, unexposed) with cytokine levels, oocyte yield and embryo quality. Results: Levels of interleukin (IL)-8 and monocyte chemoattractant protein-1 were higher in fluid obtained from endometrioma-affected ovaries compared with the unexposed ovaries from women without endometriosis, with intermediate levels observed in the contralateral unaffected ovaries. More modest differences were observed for IL-1 beta and IL-6. The affected ovaries of women with endometriosis yielded fewer oocytes (mean +/- SD = 4.6 +/- 2.3) compared with both the unaffected (6.0 +/- 3.8) and unexposed (7.9 +/- 5.6) ovaries. After adjusting for potential confounders and variables generated in a cytokine principal components analysis, oocyte yield remained slightly lower for the endometrioma-affected ovaries compared with unexposed ovaries. No informative differences among ovary groups for embryo quality parameters were observed. Conclusions: The results suggest that the inflammatory milieu of ovarian endometriosis is strongly localized and has a more modestly systemic effect. The effect of endometriomas on infertility, however, cannot be entirely explained by increased inflammation.