O-148 Does presence of endometriosis adversely affect oocyte morphology? Evaluation of a large number of oocytes obtained from endometriosis patients, 27204 oocytes

Abstract Study question Does presence of endometriosis adversely affect oocyte morphology? Evaluation of a large number of oocytes obtained from endometriosis patients, 27204 oocytes Summary answer In the presence of endometriosis, oocyte morphology is not impaired. The rate of reaching blastocyst and fertiilization rate, also pregnancy outcomes are not affected negatively. What is known already Although there are hypothesis, theories that altered steroidogenesis and folliculogenesis, higher oxidative stress, reactive oxygen species, altered cell cycle progression, inflammation and angiogenesis in the follicular environment exposes oocytes to a hostile inflammatory environment and alters oocyte quality. There has been much debate and conflicting evidence as to whether the poorer IVF outcomes in women with endometriosis is related to altered oocyte quality. There is some evidence to suggest that impaired oocyte morphology in women with endometriosis may have an adverse impact on fertilization rate, however, most studies have shown that there is no difference in pregnancy outcomes following IVF. Study design, size, duration This retrospective, single center study evaluated 29130 ART cycles from August 2011 to March 2023,based on data obtained from Istanbul Memorial Hospital,ART and Reproductive Genetics Center.Study group included endometriosis patients(n = 4602 cycles, 27204 oocytes) and control group included non-endometriosis patients(n = 24528 cycles, 178774 oocytes).We analyzed demographic and cycle characteristics, oocyte morphology in ART cycles between the two groups.Futhermore, we compared pregnancy outcomes in frozen-thawed embryo transfer(FET) cycles (total number:11116 FET cycles; endometriosis group:2255 cycles,non-endometriosis group:8861 cycles). Participants/materials, setting, methods Patients diagnosed with endometrioma by ultrasound, diagnosed with endometriosis by laparoscopy or patients who underwent endometrioma surgery or adenomyosis detected on ultrasound were included in the study (endometriosis) group. In the control group, the patients without endometriosis were included. Mann Whitney U test and Pearson Chi-square test used. Cliff's Delta effect size (????) for non-parametric tests and Phi effect size (p) for categorical data were reported. Main results and the role of chance The sample was very large, so the statistical results were given in terms of effect size, not only p value calculated. Female age was similar. Female body mass index, number of previous cycles, duration of infertility, AMH, total gonadotropin dosage used, duration of ovarian stimulation, estradiol level on trigger day, number of aspirated oocytes, mature and fertilized oocytes, maturation and fertilization rate, rate of blastulation, rate of usable blastocyst (top and good quality), number of embryos transferred, blastocyst stage embryo transfer cycles were statistically different between the two groups (p 0.001). However when the effect size examined, all variables were found to have a negligible association by Cliff's Delta or Phi effect size calculations. Oocytes obtained from endometriosis patients had statistically significantly higher severe central granulation, large perivitellin space, thick zona, polar body defect abnormalities compared to non-endometriosis patients (p 0.001), Phi effect size showed negligible association for all variables. In endometriosis group compared to non endometriosis group; biochemical pregnancy (68.9% vs 72.2%, p:0.002, Phi:0.030), clinical pregnancy (61.5% vs 64.5%, p:0.007, Phi:0.025), total pregnancy loss (22% vs 24.4%, p:0.05, Phi:0.022) were statistically higher, but Phi effect sizes were negligible. Live birth were similar (52.5% vs 53.2 P:0.56) between the two groups. Limitations, reasons for caution The principal limitation of the study is retrospective design of the analysis. But the strength of the study is that included 27204 oocytes from endometriosis patients. Wider implications of the findings To our knowledge, this study includes the largest case group that investigates the endometriosis and oocyte morphology. The results show that endometriosis does not have a negative impact on oocyte morphology. Additionally, it has been shown that the presence of endometriosis does not have a negative effect on pregnancy outcomes. Trial registration number *