Average oocyte quality index as a method for scoring dysmorphic oocytes in women with ovarian endometrioma undergoing in vitro fertilization and its correlation with ovarian reserve

This study investigated whether the average oocyte quality index (AOQI), used as a dysmorphic oocyte scoring system, is higher in women with ovarian endometrioma than in those with unexplained infertility or diminished ovarian reserve (DOR).

We included 92 intracytoplasmic sperm injection cycles in which one to five metaphase II oocytes were obtained, and the AOQI was calculated in each cycle. Cycles were grouped according to the indication for in vitro fertilization: current or recurrent endometrioma (34 cycles), unexplained infertility (26 cycles), and DOR (32 cycles). DOR was defined by a serum anti-Müllerian hormone (AMH) level <1.0 ng/mL. The AOQI was compared among the three groups, and the relationship between serum AMH levels and AOQI was also analyzed.

The median AOQI value was significantly higher in the endometrioma group (1.50) compared to the unexplained infertility group (1.00) (p=0.037), but not compared to the DOR group (1.42). Overall, serum AMH level showed an inverse correlation with the AOQI (r=– 0.242, p=0.02). Serum AMH level was also inversely correlated with the AOQI in the endometrioma group (r=–0.429, p=0.011), but not in the unexplained infertility and DOR groups. Multiple linear regression analysis demonstrated that serum AMH levels remained inversely correlat- ed with the AOQI (B=–0.176; 95% confidence interval, –0.327 to –0.024; p=0.024), whereas the presence of endometrioma was not a signifi- cant factor.

The AOQI in the ovarian endometrioma group was higher compared to the unexplained infertility group, and this difference ap- peared to arise primarily from reduced ovarian reserve rather than the direct impact of endometrioma itself. Serum AMH levels showed an inverse correlation with AOQI, emphasizing the central role of ovarian reserve in determining oocyte quality.

Anti-Mullerian hormone; Endometriosis; Infertility; Oocytes

Endometriosis is a chronic inflammatory condition characterized by endometrial-like tissue located outside the uterus, with ovarian endometrioma representing one of its most common manifestations [1]. This disease can significantly affect women’s reproductive health, particularly in those undergoing in vitro fertilization (IVF), where re- productive outcomes may be compromised [2 ]. Multiple studies have demonstrated that the presence of endometrioma may ad- versely affect ovarian reserve and the response to stimulation during IVF treatments [3]. There is ongoing debate regarding whether oocyte and embryo line space, fragmented polar body, and the overall oocyte morpholo- gy score represented by the AOQI [12]. Despite increasing interest in the impact of endometriosis on re- productive outcomes, relatively few studies have directly compared oocyte quality indices between women with ovarian endometrioma and those with other forms of infertility. Notably, limited research has examined AOQI differences between women with endometrio- ma and those with diminished ovarian reserve (DOR) of various etiol- ogies [13,14]. The relationship between ovarian reserve markers and oocyte quality in patients with endometrioma also remains unclear, as current evidence offers conflicting conclusions regarding whether both oocyte quantity and quality are similarly affected [15]. Therefore, this study sought to analyze AOQI differences in women with ovarian endometrioma undergoing IVF and to assess its correla- tion with ovarian reserve. By doing so, it aims to contribute to a more comprehensive understanding of reproductive outcomes in these patients and to inform clinical decision-making for treatment optimi- zation. This study specifically aims to determine whether the AOQI is higher in women with ovarian endometrioma than in those with un- explained infertility or DOR. In addition, the association between se- rum AMH levels and AOQI was also assessed.

1. Study population This study was conducted at Seoul National University Bundang Hospital. We included 92 ICSI cycles (49 women) in which one to five MII oocytes were obtained between January 2023 and September 2024. The study was approved by the Institutional Review Board of Seoul National University Bundang Hospital (IRB No. B-2508-989- 109), and the requirement for informed consent was waived because of its retrospective design. Each cycle was assigned to one of three groups according to the primary indication for IVF treatment: current or recurrent ovarian en- dometrioma (34 cycles), unexplained infertility (26 cycles), and DOR, defined as a serum AMH level <1.0 ng/mL (32 cycles). Demographic and clinical information was retrieved from electronic medical re- cords. Exclusion criteria included patients with a prior history of endome- trioma surgery without evidence of current endometrioma, as well as those undergoing IVF for other indications such as tubal factor in- fertility or male factor infertility. 2. Ovarian stimulation and IVF procedure Ovarian stimulation protocols were selected based on patient age, ovarian reserve, and previous response to stimulation, following standard clinical practice at our institution [16]. Pituitary suppression quality are reduced in IVF patients with endometriosis compared to those with other infertility etiologies. Several studies have explored correlations between oocyte quality parameters and IVF outcomes across various patient populations, yet findings remain inconsistent regarding the specific impact of endometrioma on oocyte compe- tence [4,5]. A previous study suggested that women with endome- triosis-associated infertility tend to have reduced oocyte quality compared to those with other infertility factors, potentially contrib- uting to lower implantation and pregnancy outcomes [6]. Some have proposed that endometrioma primarily affects ovarian reserve rather than oocyte quality itself [7]. In a retrospective study by Benaglia et al. [8], although the number of oocytes collected from women with endometriosis was smaller, fertilization rates, embryo quality, implantation rates, pregnancy rates, and live birth rates were comparable to those in women with other infertility factors. Similar- ly, Kamath et al. [9] reported that live birth rates per cycle in women with endometriosis were similar between cycles using donor oocytes and cycles using autologous oocytes. Based on such findings, endo- metriosis does not appear to exert a substantial adverse effect on oocyte or embryo quality. Nevertheless, previous studies did not directly analyze oocyte quality, but instead evaluated it indirectly by comparing fertilization rates. The assessment of oocyte quality is essential for predicting em- bryo developmental potential and ultimately the success of IVF pro- cedures. In intracytoplasmic sperm injection (ICSI) cycles, dysmor- phic metaphase II (MII) oocytes are frequently associated with re- duced fertilization and cleavage rates. Dysmorphic oocytes exhibit cytoplasmic granulation, abnormal cytoplasm (including vacuoles, refractile bodies, or smooth endoplasmic reticulum), abnormal oo- cyte shape, and alterations of the zona pellucida, perivitelline space, or polar body. The average oocyte quality index (AOQI) was introduced as a mor- phological oocyte scoring system in which the total number of ab- normalities in MII oocytes is counted, and the index is calculated as the ratio of abnormalities to the total number of MII oocytes [10]. Si- gala et al. [10] evaluated abnormalities across seven morphological categories, including cytoplasmic granularity, irregular shape or thickened zona pellucida, intracytoplasmic vacuoles, material within the zona pellucida, anomalies of the first polar body, large perivitel- line space, and oocyte shape [10]. In one retrospective study, the AOQI was similar between women with and without endometriosis. However, two specific abnormali- ties, abnormal oocyte shape and intracytoplasmic vacuoles, were observed more frequently in women with endometriosis [11]. An- other retrospective study found that serum anti-Müllerian hormone (AMH) level was inversely associated with cytoplasmic granulation, abnormally amorphous oocytes, extended or granulated perivitel- https://doi.org/10.5653/cerm.2025.084382 Clin Exp Reprod Med [Epub ahead of print] was performed using either a gonadotropin-releasing hormone (GnRH) agonist long protocol or a GnRH antagonist protocol. Recom- binant follicle-stimulating hormone and/or human menopausal go- nadotropin was administered for stimulation, with dosing individu- alized to each patient’s characteristics. Ovulation was triggered with human chorionic gonadotropin (hCG) once at least two follicles reached a diameter of ≥18 mm. Transvaginal ultrasound-guided oocyte retrieval was performed 35 to 36 hours after hCG administration. Retrieved oocytes were incu- bated in culture medium, and ICSI was performed on MII oocytes fol- lowing standard laboratory procedures. 3. AOQI assessment The AOQI was calculated for each cycle. First, oocytes were evalu- ated under a microscope by experienced embryologists, and one or more dysmorphic features were documented. Dysmorphic features were categorized into six groups and further classified into 15 de- tailed items: cytoplasmic granulation (granulation or central gran- ules), abnormal cytoplasm (vacuoles, refractile bodies, or smooth en- doplasmic reticulum), abnormal shape (oval, amorphic, or dark), ab- normal perivitelline space (extended or containing debris), abnormal polar body (fragmentation, double, or large), and abnormal zona pellucida (thin or thick) (Figure 1). The AOQI was then determined as the ratio of the total number of abnormalities to the total number of MII oocytes in each cycle. Among 251 MII oocytes obtained, 208 (82.9%) had at least one dysmorphic feature. 4. Statistical analysis Statistical analyses were performed using SPSS ver. 25.0 (IBM Corp.). Continuous variables were presented as median values with interquartile ranges. Categorical variables were reported as number (percentage). The Kolmogorov-Smirnov test was applied to assess normality. Comparisons among the three groups were conducted using the Kruskal-Wallis test for continuous variables, followed by appropriate post hoc tests. Categorical variables were compared us- ing the chi-square test or Fisher exact test when applicable. The rela- tionship between serum AMH levels and AOQI was examined using Spearman’s rho for the overall cohort as well as separately for each of the three groups. Multiple linear regression analysis was also per- formed to identify independent factors associated with AOQI, adjust- ing for the presence of ovarian endometrioma and serum AMH lev- els.

Women with ovarian endometrioma were significantly younger than those with unexplained infertility and DOR (p<0.001) (Table 1). The median serum AMH levels were highest in the unexplained infer- tility group and lowest in the DOR group (p<0.001 for all comparisons). The number of MII oocytes retrieved was significantly higher in the unexplained infertility group compared to the other groups (p<0.05). The median AOQI value was significantly higher in the endometrioma group (1.50) than in the unexplained infertility group (1.00) (p=0.037), although it did not differ significantly from the DOR group (1.42). With regard to specific oocyte abnormalities, cytoplasmic granula- tion was most prevalent in the endometrioma group compared to the other two groups (p<0.05), whereas abnormal cytoplasm was least prevalent in the endometrioma and unexplained infertility groups compared to the DOR group (p<0.001) (Figure 2). Despite these morphological differences, fertilization rates were comparable across all three groups ( Table 1). The endometrioma group showed the highest percentage of top-quality embryos (36.7%), which was significantly higher than that of the DOR group (0%, p=0.043). Figure 1. Representative dysmorphic oocyte images categorized into six feature groups and further detailed by 15 specific items. www.eCERM.org 3 J H Park et al. Average oocyte quality index and ovarian reserve Granulation Vacuoles Oval Fragmention Extended Thin Amorphic Double Debris Thick Dark Huge Central granules Smooth endoplasmic reticulum Refractile body Table 1. IVF cycle characteristics including the AOQI and distribution of detailed oocyte abnormalities in three groups Endometrioma (34 cycles) a) Unexplained infertility (26 cycles) b) Diminished ovarian reserve (32 cycles) c) p-value Post hoc Age of female 36 (34–39) 41 (38.5–43.3) 42.5 (40–45.8) 0.001 a),b) p < 0.001 a),c) p < 0.001 Serum anti-Müllerian hormone level (ng/mL) 0.86 (0.59–1.41) 2.03 (1.4–3.29) 0.46 (0.1–0.75) 0.001 a),b) p < 0.001 a),c) p < 0.001 b),c) p < 0.001 Serum estradiol at triggering day (pg/mL) 707 (476–1,171) 1,687 (965–2,175) 671 (339–948) 0.001 a),b) p < 0.001 b),c) p < 0.001 No. of total MII oocytes 2 (2–4) 4 (2.8–4) 2 (1–3) 0.007 a),b) p = 0.02 b),c) p = 0.003 No. of dysmorphic MII oocytes 2 (1.8–3) 2.5 (2–4) 2 (1–2.8) 0.022 b),c) p = 0.009 No. of total abnormalities 4 (2–6) 4 (2–5) 3 (2–4) 0.284 AOQI 1.50 (1.00–2.13) 1.00 (0.75–1.43) 1.42 (1–2) 0.037 a),b) p = 0.01 From total MII oocytes No. of fertilized oocytes 2 (1–3) 3 (1–4) 2 (1–3) 0.048 b),c) p = 0.023 Fertilization rate (%) 100 (66.7–100) 100 (66.7–100) 100 (68.8–100) 0.748 Embryo score at day-3 27.5 (22.6–32) 26.9 (19.4–32) 24 (22.4–30.1) 0.389 Top-quality embryo at day-3 per total MII oocyte (%) 36.7 (0–100) 20 (0–50) 0 (0–50) 0.115 Values are presented as median (interquartile range). Comparisons between the three groups were performed using the Kruskal-Wallis test, followed by the Mann-Whitney U test. AOQI, average oocyte quality index; MII, metaphase II. Figure 2. Distribution of specific oocyte abnormalities in the endometrioma, unexplained infertility, and diminished ovarian reserve groups. a),b) p<0.05; c),d) p<0.05. https://doi.org/10.5653/cerm.2025.084384 Clin Exp Reprod Med [Epub ahead of print] Cytoplasminc granulation Abnormal ctroplasm Abnormal shape Abnormal perivitelline space Abnormal polar baby Abnormal zona pellucida Endometriona 46.3% 17.5% 25.0% 32.5% 43.8% 23.8% Unexplained infertility 29.0% 11.6% 20.3% 23.2% 43.5% 20.3% Diminished ovarian reserve 28.8% 47.5% 13.6% 47.5% 42.4% 25.4% 50.0% 45.0% 40.0% 35.0% 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0% a) b) b) c) c) d) Table 3. Correlation between serum anti-Müllerian hormone levels and AOQI in three groups r p-value Endometrioma –0.429 0.011 Unexplained infertility –0.259 0.201 Diminished ovarian reserve 0.259 0.152 Spearman rho test. AOQI, average oocyte quality index. In the overall study population, median serum AMH levels demon- strated significant positive correlations with both the number of total MII oocytes and the number of dysmorphic MII oocytes, while show- ing a significant negative correlation with AOQI (r=–0.242, p=0.020) (Table 2). When each group was analyzed separately, this negative correlation between serum AMH level and AOQI was statistically sig- nificant only in the endometrioma group (r=–0.429, p=0.011) (Table 3). Regression lines illustrating these associations are shown in Figure 3, depicting the relationship between serum AMH levels and AOQI in the overall study population (Figure 3A) and in the endometrioma (Figure 3B), unexplained infertility (Figure 3C), and DOR (Figure 3D) groups. Because the median AOQI was significantly higher in the endome- trioma group and a significant negative correlation between serum AMH level and AOQI was observed in both the endometrioma group and the overall cohort, a multiple linear regression analysis was per- formed using two variables: presence of endometrioma and serum AMH level. Female age was not associated with AOQI (r =–0.164, p=0.118), and therefore was not included in the multiple linear re- gression model. Table 2. Correlation between serum anti-Müllerian hormone levels and four variables, including the AOQI r p-value No. of total MII oocytes 0.473 0.001 No. of dysmorphic MII oocytes 0.403 0.001 No. of total abnormalities 0.216 0.039 AOQI –0.242 0.020 Spearman rho test. AOQI, average oocyte quality index; MII, metaphase II. Figure 3. Regression lines depicting the correlation between serum anti-Müllerian hormone (AMH) levels and the average oocyte quality index (AOQI) in the overall study population (A), the endometrioma group (B), the unexplained infertility group (C), and the diminished ovarian reserve group (D). r=–0.242, p=0.02 r=–0.429, p=0.011 r=–0.259, p=0.201 r=0.259, p=0.152 Multiple linear regression analysis showed that serum AMH level remained a significant independent factor negatively associated www.eCERM.org 5 J H Park et al. Average oocyte quality index and ovarian reserve AOQI AOQI AOQI AOQI 4.00 3.00 2.00 1.00 0 3.00 2.50 2.00 1.50 1.00 0.50 3.00 2.50 2.00 1.50 1.00 0.50 0 4.00 3.00 2.00 1.00 0 AMH AMH AMH AMH 0 0 0 0.20 0.40 0.60 0.80 1.000 0.50 1.00 1.001.00 1.50 2.00 2.002.00 3.00 3.00 4.00 4.00 5.00 5.00 6.00 6.00 AA BB CC DD with AOQI (unstandardized coefficient=–0.176; 95% confidence in- terval, –0.327 to –0.024; p=0.024), whereas the presence of endome- trioma was not a significant factor (Table 4).

Our study addressed an important gap in the current literature by specifically examining the relationship between oocyte quality and ovarian reserve in women with endometrioma, comparing them not only with those who had unexplained infertility but also with those who had DOR. Previous studies primarily compared endometriosis patients with normal controls or patients with tubal factor infertility, without adequately accounting for the potential confounding effect of DOR, which frequently coexists with endometriosis [17,18]. In our study, women with ovarian endometrioma demonstrated significantly higher AOQI values (indicating poorer oocyte quality) compared to those with unexplained infertility. However, we also observed that higher AMH levels corresponded to better oocyte quality among women with ovarian endometrioma. This finding suggests that oocyte quality varies according to ovarian reserve even among women who share the same diagnosis of endometrioma. Multiple linear regression analysis further revealed that endometrio- ma itself was not a significant factor associated with AOQI; instead, serum AMH level remained the only significant independent factor. Thus, the elevated AOQI observed in the endometrioma group ap- pears to be primarily attributable to reduced ovarian reserve rather than the direct impact of endometrioma. In our study, female age and AOQI were unrelated, and therefore age was not included as a variable in the multiple linear regression analysis. For reference, we also found no correlation between female age and AMH (r=–0.140, p=0.184). This finding warrants further con- sideration, particularly given that our endometrioma group included women with a broad range of AMH levels and our DOR group includ- ed women across a wide age spectrum. Consequently, within this study population, there appeared to be no negative relationship be- tween age and AMH. In our study, cytoplasmic granulation was the predominant oocyte abnormality in the endometrioma group, whereas abnormal cyto- plasm was more prevalent in the DOR group. The higher prevalence of cytoplasmic granulation among women with endometrioma may reflect the inflammatory microenvironment associated with endo- metriotic lesions. Endometriomas are known to produce elevated levels of inflammatory cytokines, reactive oxygen species, and iron derived from hemolyzed blood, all of which may diffuse into adja- cent ovarian tissue and disrupt folliculogenesis [7]. Such oxidative stress can impair mitochondrial function in oocytes, potentially re- sulting in cytoplasmic granulation as a morphological indicator of mitochondrial clustering or dysfunction [6]. Our findings are consistent with several prior studies that have re- ported altered oocyte morphology in women with endometriosis. Xu et al. [18] identified a higher incidence of cytoplasmic granularity and vacuolization in oocytes from endometriosis patients compared with those from women with tubal factor infertility. Likewise, Goud et al. [17] observed that oocytes from women with advanced-stage endometriosis exhibited increased oxidative stress markers and mi- tochondrial DNA deletions, both of which correlated with abnormal cytoplasmic appearance. The major strength of our study lies in its comparative design, which incorporated three distinct patient groups representing differ- ent infertility etiologies. Additionally, our detailed assessment of spe- cific oocyte abnormalities, as opposed to simply categorizing oo- cytes as normal or abnormal, provided deeper insights into potential mechanisms by which endometriosis influences oocyte develop- ment. Nonetheless, several limitations should be acknowledged. First, our analysis was limited to cycles in which one to five MII oocytes were retrieved, which may not fully represent the range of ovarian responses seen in these populations. It is possible that the effects of DOR were accentuated by excluding cycles with greater oocyte yields. Second, final embryo development was evaluated without distinguishing between embryos derived from dysmorphic versus morphologically normal oocytes, as our study was not intended to investigate the specific developmental potential of dysmorphic oo- cytes. Future research should assess embryo development separate- ly for dysmorphic and normal oocytes to clarify their respective con- tributions to reproductive outcomes. Collectively, the AOQI may serve as a comprehensive marker that reflects both morphological and cytoplasmic characteristics of oo- cytes. Our study demonstrates that women with ovarian endometri- oma exhibit distinct patterns of oocyte morphological abnormalities, particularly cytoplasmic granulation, compared with those with un- explained infertility or DOR. Prospective studies with larger sample sizes and long-term follow-up are needed to further elucidate the re- lationship between oocyte morphology, developmental compe - tence, and reproductive outcomes in women with endometrioma. Table 4. Multiple linear regression analysis of factors influencing the AOQI in overall population Unstandardized coefficient (B) t 95% confidence Interval p-value Endometrioma 0.192 1.069 –0.165 to 0.548 0.288 Serum AMH –0.176 –2.303 –0.327 to –0.024 0.024 AOQI, average oocyte quality index; AMH, anti-Mullerian hormone. https://doi.org/10.5653/cerm.2025.084386 Clin Exp Reprod Med [Epub ahead of print] Conflict of interest Byung Chul Jee has served as the editor-in-chief of Clinical and Ex- perimental Reproductive Medicine since 2018. However, he did not participate in the selection, evaluation, or decision-making process for the peer review of this article. No potential conflicts of interest re- lated to this article have been reported. Author contributions Conceptualization: BCJ. Methodology: JHP , BCJ. Formal analysis: JHP , SKK, BCJ. Data curation: SKK, BCJ. Project administration: SKK, BCJ. Writing-original draft: JHP , SKK, BCJ. Writing-review & editing: JHP , SKK, BCJ. Approval of final manuscript: JHP , SKK, BCJ. ORCID Ju Hee Park https://orcid.org/0000-0001-5094-1640 Seul Ki Kim https://orcid.org/0000-0002-1647-6711 Byung Chul Jee https://orcid.org/0000-0003-2289-6090

1. Burney RO, Giudice LC. Pathogenesis and pathophysiology of en- dometriosis. Fertil Steril 2012;98:511-9. 2. AlKudmani B, Gat I, Buell D, Salman J, Zohni K, Librach C, et al. In vitro fertilization success rates after surgically treated endometri- osis and effect of time interval between surgery and in vitro fertil- ization. J Minim Invasive Gynecol 2018;25:99-104. 3. Chon SJ, Jee BC. Oocyte cryopreservation for women with endo- metriosis: justification, indications, and reproductive outcomes. Clin Exp Reprod Med 2024;51:277-84. 4. Li F , Chen S, Zhang W, Wang L, Li D, Wu J. Modified GnRH antago- nist protocol improves oocyte yield in anovulatory women with endometriosis and diminished ovarian reserve. Front Endocrinol 2020;11:316. 5. Demirel C, Bastu E, Aydogdu S, Donmez E, Benli H, Tuysuz G, et al. The presence of endometrioma does not impair time-lapse mor- phokinetic parameters and quality of embryos: a study on sibling oocytes. Reprod Sci 2016;23:1053-7. 6. Radzinsky VY , Orazov MR, Ivanov II, Khamoshina MB, Kostin IN, Kavteladze EV, et al. Implantation failures in women with infertili- ty associated endometriosis. Gynecol Endocrinol 2019;35:27-30. 7. Zeng Y, Li K, Ouyang C, Zhang C, Yang M, Wu H. Ovarian response in women with endometriosis with different characteristics and correlation with endometriotic lesion-surrounding CD40/CD40L expression. Front Endocrinol 2022;13:858266. 8. Benaglia L, Bermejo A, Somigliana E, Faulisi S, Ragni G, Fedele L, et al. In vitro fertilization outcome in women with unoperated bi- lateral endometriomas. Fertil Steril 2013;99:1714-9. 9. Kamath MS, Subramanian V, Antonisamy B, Sunkara SK. Endome- triosis and oocyte quality: an analysis of 13 614 donor oocyte re- cipient and autologous IVF cycles. Hum Reprod Open 2022;2022: hoac025. 10. Sigala J, Sifer C, Dewailly D, Robin G, Bruyneel A, Ramdane N, et al. Is polycystic ovarian morphology related to a poor oocyte quality after controlled ovarian hyperstimulation for intracyto- plasmic sperm injection?: results from a prospective, comparative study. Fertil Steril 2015;103:112-8. 11. Robin C, Uk A, Decanter C, Behal H, Collinet P , Rubod C, et al. Im- pact of endometriosis on oocyte morphology in IVF-ICSI: retro- spective study of a cohort of more than 6000 mature oocytes. Re- prod Biol Endocrinol 2021;19:160. 12. Azizi E, Naji M, Nazari L, Salehpour S, Karimi M, Borumandnia N, et al. Serum anti-Mullerian hormone is associated with oocyte dysmorphisms and ICSI outcomes. Int J Gynaecol Obstet 2019;147:179-86. 13. Roustan A, Perrin J, Debals-Gonthier M, Paulmyer-Lacroix O, Agostini A, Courbiere B. Surgical diminished ovarian reserve after endometrioma cystectomy versus idiopathic DOR: comparison of in vitro fertilization outcome. Hum Reprod 2015;30:840-7. 14. Ozelci R, Dilbaz B, Aksoy RT, Tanriverdi ED, Dilbaz S. The effect of laterality and diameter of the ovarian endometrioma on oocyte quality, embryo quality and pregnancy rate. Gynecol Obs Reprod Med 2019;25:124-9. 15. Opoien HK, Fedorcsak P , Byholm T, Tanbo T. Complete surgical re- moval of minimal and mild endometriosis improves outcome of subsequent IVF/ICSI treatment. Reprod Biomed Online 2011;23:389-95. 16. Paik H, Jeong HG, Jee BC. Cumulative pregnancy rate via multiple fresh or frozen embryo transfers in women with current, resected, or recurred endometrioma. Taiwan J Obstet Gynecol 2023;62:677- 81. 17. Goud PT, Goud AP , Joshi N, Puscheck E, Diamond MP , Abu-Soud HM. Dynamics of nitric oxide, altered follicular microenvironment, and oocyte quality in women with endometriosis. Fertil Steril 2014;102:151-9. 18. Xu B, Guo N, Zhang XM, Shi W, Tong XH, Iqbal F , et al. Oocyte qual- ity is decreased in women with minimal or mild endometriosis. Sci Rep 2015;5:10779. www.eCERM.org 7 J H Park et al. Average oocyte quality index and ovarian reserve