Polycystic ovary syndrome phenotype does not have impact on oocyte morphology.

PURPOSE: The primary objective of the present study of women participating in an ICSI program was to determine whether the morphologic quality of oocytes was related to the polycystic ovary syndrome (PCOS) phenotype. METHODS: We performed a retrospective cohort study in the IVF unit at the Lille University Medical Center (Lille, France) between 2006 and 2015. Oocyte morphology (fragmented first polar body, abnormal zona pellucida, large perivitelline space, material in perivitelline space, abnormal shape of oocyte, granular cytoplasm and intracytoplasmic vacuoles) was evaluated in PCOS women and according to different subgroup (depending on the presence or absence of the cardinal features polycystic ovarian morphology (PCOM), hyperandrogenism (HA), and oligo-anovulation (OA)). RESULTS: A total of 1496 metaphase II oocytes (n = 602 for phenotype A combining PCOM + HA + OA, n = 462 oocytes for phenotype C: PCOM + HA, and n = 432 for phenotype D: PCOM + OA) were assessed. The phenotypes A, C and D did not differ significantly with regard to the proportion of normal oocytes (adjusted percentages (95%CI): 35.2% (31.5 to 39.1%), 25.8% (21.9 to 29.9%) and 34.0% (29.7 to 38.6%), respectively: adjusted p = 0.13). Likewise, there were no significant intergroup differences in oocyte morphology. The ICSI outcome was not significantly associated with the PCOS phenotype. CONCLUSION: The present study is the first to show that the PCOS phenotype (notably the presence vs. absence of OA and/or HA) is not significantly associated with the morphological quality of oocytes.

Maternal lifestyle and nutritional habits are associated with oocyte quality and ICSI clinical outcomes.

RESEARCH QUESTION: Do maternal lifestyle factors influence the incidence of oocyte dimorphisms and outcomes of intracytoplasmic sperm injection (ICSI) cycles? DESIGN: A total of 752 female patients undergoing an ICSI cycle at a private university-affiliated IVF centre from January 2015 to December 2019 were included in this historical cohort study. Before starting ovarian stimulation, participants completed a questionnaire on cigarette smoking habits, consumption of alcoholic beverages, refined sugar, artificial sweeteners, soft drinks, fruits, legumes and vegetables, milk and dairy, and meat, as well as exercise frequency over the past 6 months. Oocyte morphology was evaluated before ICSI. The influence of maternal lifestyle factors on the incidence of oocyte dimorphisms and ICSI outcomes was evaluated by multivariate general linear models and generalized linear models, adjusted for potential confounders. The main outcome measures were the incidence of oocyte dimorphisms per cycle and clinical outcomes. RESULTS: Lifestyle factors and nutritional habits such as cigarette smoking, and the consumption of alcohol, refined sugar and artificial sweeteners, were positively associated with incidence of several oocyte dimorphisms and negatively associated with the response to ovarian stimulation and embryo development. Negative relationships were also observed between these habits and clinical outcomes, apart from miscarriage rate, in which positive relationships were observed. Significant negative dose-dependent relationships between these habits and implantation rates were noted (P < 0.001). Alcoholic beverage consumption also showed inverse dose-dependent relationships with clinical pregnancy and live birth rates. Live birth rate was also negatively associated with cigarette smoking, in a dose-dependent manner. CONCLUSIONS: Poor maternal habits were associated with reduced oocyte quality and ICSI outcomes in this study. Many of these associations were shown to be dose-dependent.

Higher quality rather than superior quantity of oocytes determine the amount of fertilizable oocytes in two outbred Dummerstorf high-fertility mouse lines.

Dummerstorf fertility lines FL1 and FL2 represent two models of enhanced fertility characterized by the doubling of the litter size compared with an unselected control population (ctrl line, Dummerstorf FztDU). Both biodiverse FLs managed to reach this goal by increasing the ovulation rate per cycle, even showing decreased pregnancy rate and irregular oestrous cycle and metabolic hormone levels, compared with ctrl. The aim of the present study was to analyse oocytes in terms of quality and quantity by comparing the entire pool of oocytes per ovary, with those from the antral follicles within the same animal. We performed Brilliant Cresyl Blue staining as a non-invasive marker of oocyte quality in combination with an analysis of additional morphological indicators, e.g. cytoplasm clarity, cumulus cell layers, nuclear anatomy, size and shape. We compared our fertility lines with the unselected control population and with another independent line selected from the same founder population, showing lower litter size (DU6P). Our results suggest that fertility lines show decreased number of oocytes per ovary compared with DU6P but increased number of high-quality oocytes before ovulation. Hence, the raise in the ovulation rate and litter size of those super fertile mouse lines are not associated with an increased number of oocytes per ovary but rather with an increased number of higher quality fertilizable oocytes per cycle. In addition, the most conspicuous method to acquire oocytes with the highest quality in our lines is to assess their morphology, rather than their status after staining. All these discoveries together may be of fundamental importance for further studies in livestock farm animals showing some similar characteristics, e.g. irregular cycle or hormonal misbalances, to improve production while lowering costs, and in humans to increase the possibilities of successful pregnancies for couples undergoing in vitro fertilization (IVF).

The rate of oocytes with granular cytoplasm is higher in women with endometrioma in ICSI cycles.

The purpose of this study was to investigate the impact of endometrioma on oocyte morphology and fertility outcome in intracytoplasmic sperm injection (ICSI)cycles. The study material was obtained from 114 ICSI cycles of infertile women aged between 20 and 38 years with ovarian endometriomas and unexplained infertility. In total, 644 mature oocytes were included in the analysis. The rates of specific oocyte morphological abnormalities were similar between the two groups however the central granulation rate was significantly higher in the group with endometrioma (p < .05). Fertilisation rate were not significantly different between the groups (p ≥ .05) however the numbers of metaphase 2 (MII) oocytes and embryos were lower in the endometrioma group (p ≤ .05). Endometrioma was associated with a higher rate of oocytes with granular cytoplasm, despite the fertilisation rate the numbers of the MII oocytes and embryo were affected.IMPACT STATEMENTWhat is already known on this subject? The association between endometrioma and infertility is a well-known condition, but the possible mechanisms of the effects of endometrioma on women's fertility is still debated and controversial. There is limited data on the effect of endometrioma on oocyte morphology. Low oocyte quality and lower fertilisation rates might be the main cause of adverse pregnancy outcomes during in vitro fertilisation/intracytoplasmic sperm injection cycles.What do the results of this study add? Endometrioma was associated with a higher rate of oocytes with granular cytoplasm, and lower metaphase 2 oocytes and embryos.What are the implications of these findings for clinical practice and/or further research? Future studies using further oocyte quality assessment methods and prospective observational studies including live-birth rate should be designed to better understand how endometrioma affects fertility outcomes.

Occurrence of smooth endoplasmic reticulum aggregates in metaphase II oocytes: relationship with stimulation protocols and outcome of ICSI and IVF cycles.

STUDY QUESTION: Is there any association between the appearance of smooth endoplasmic reticulum aggregates (SERa) in oocytes and ovarian stimulation, embryological, clinical and neonatal outcomes of ICSI and IVF cycles? SUMMARY ANSWER: A suboptimal prolonged ovarian stimulation is detrimental to oocytes by inducing the occurrence of SERa, which reduces the reproductive potential of oocytes. WHAT IS KNOWN ALREADY: Controlled ovarian stimulation recruits oocytes of different qualities. Based on current evidence, it was agreed that non-homogeneous cytoplasm may represent the normal variability among oocytes rather than a dysmorphism with developmental significance. The only exception is the appearance of SERa within the ooplasm. Owing to the lack of univocal evidence in this literature about the safety of injecting oocytes with SERa and the mechanism responsible for the occurrence of SERa, this topic is still a matter of debate. STUDY DESIGN, SIZE, DURATION: A retrospective, longitudinal cohort study performed at a tertiary level public infertility center. We included 1662 cycles (180 SERa+ and 1482 SERa-) from 1129 women (age: 20-44 years) who underwent IVF/ICSI treatments in 2012-2019. The SERa+ cycles had at least one SERa+ oocyte in the oocyte cohort. The SERa- cycles had morphologically unaffected oocytes. PARTICIPANTS/MATERIALS, SETTING, METHODS: We collected stimulation data and embryological, clinical, neonatal outcomes of SERa- and SERa+ cycles and oocytes. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 347 out of 12 436 metaphase II oocytes (2.8%) were affected by SER. We performed only 12 transfers involving at least one SERa+ embryo. Stimulation length (P = 0.002), serum progesterone (P = 0.004) and follicle size (P = 0.046) at trigger, number of retrieved (P = 0.004) and metaphase II (P = 0.0001) oocytes were significantly higher in SERa+ than SERa- cycles. Fertilization rate was significantly (P < 0.0001) reduced in SERa+ cycles and oocytes compared to SERa- counterparts. Embryos of SERa+ cycles had a lower blastocyst formation rate compared to embryos of SERa- cycles (P = 0.059). Statistical analysis according to a generalized estimating equation model performed at patient level demonstrated that the duration of ovarian stimulation was predictive of SERa+ oocytes appearance. The clinical success of SERa+ cycles was lower than SERa- cycles, although no differences in neonatal birthweights or malformations were recorded in sibling unaffected oocytes of SERa+ cycles. LIMITATIONS, REASONS FOR CAUTION: Given that SERa+ oocytes were discarded in our center for years and transfers of embryos originating from affected oocytes were generally avoided, clinical outcomes of SERa+ cycles are largely attributable to the transfer of embryos derived from unaffected oocytes of SERa+ cycles and we did not have data about newborns from affected oocytes, since none of the transfers involving SERa+ embryos resulted in a progressive clinical pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: For the first time, we speculate that the late-follicular phase elevated serum progesterone caused by a suboptimal prolonged ovarian stimulation may be detrimental to the oocytes by inducing the occurrence of SERa, resulting in negative effects on their reproductive potential. This raises the question of whether some stimulation regimens could be worse than others and a change in stimulation protocol would reduce the possibility of producing oocytes with suboptimal maturation. In particular, our data highlight the importance of correct timing of the trigger in order to maximize oocyte collection, not only in terms of numerosity but also their reproductive potential. STUDY FUNDING/COMPETING INTEREST(S): None. TRIAL REGISTRATION NUMBER: N/A.

Impact of endometriosis on oocyte morphology in IVF-ICSI: retrospective study of a cohort of more than 6000 mature oocytes.

BACKGROUND: Infertility associated with endometriosis can be explained by several non-exclusive mechanisms. The oocyte plays a crucial role in determining embryonic competence and this is particularly relevant for in vitro fertilization (IVF) outcomes. According to some authors, the morphology of oocytes could also be a non-invasive marker of oocyte quality. The aim of this study was to evaluate the relationship between endometriosis and oocyte morphology after controlled ovarian stimulation for intracytoplasmic sperm injection (ICSI) on a large oocyte cohort. METHODS: Single-center comparative retrospective study in the academic In Vitro Fertilization (IVF) unit of the Lille University Hospital. A total of 596 women treated for IVF-ICSI with ejaculated spermatozoa for sperm alterations were included. They were classified as endometriosis (n = 175) or control groups (n = 401). The morphological evaluation of 2,016 mature oocytes from 348 cycles of patients with endometriosis was compared with that of 4,073 mature oocytes from 576 control cycles. The main outcome measures were Average Oocyte Quality Index (AOQI) and metaphase II oocyte morphological scoring system (MOMS). Comparison of groups was carried out by a mixed linear model and by a generalized estimation equation model with a "patient" random effect to consider that a patient might have several attempts. RESULTS: No difference in AOQI and MOMS scores was found between endometriosis and control women (adjusted p = 0.084 and 0.053, respectively). In case of endometriosis, there were significantly fewer metaphase II oocytes retrieved, embryos obtained, grade 1 embryos and number of cumulative clinical pregnancies compared to controls. In the endometriosis group, endometriosis surgery was associated with a reduced number of mature oocytes retrieved, and the presence of endometrioma(s) was associated with some abnormal oocyte shapes. Nevertheless, no difference concerning the AOQI and MOMS scores was found in these subgroups. CONCLUSION: Endometriosis does not have a negative impact on oocytes' morphology in IVF-ICSI. TRIAL REGISTRATION: On December 16, 2019, the Institutional Review Board of the Lille University Hospital gave unrestricted approval for the anonymous use of all patients' clinical, hormonal and ultrasound records (reference DEC20150715-0002).

Clusters of smooth endoplasmic reticulum are absent in oocytes from unstimulated women.

RESEARCH QUESTION: What is the frequency of morphological dysmorphisms in immature human oocytes collected ex vivo from small antral follicles and matured in vitro? DESIGN: Human ovaries (n = 56) were excised for ovarian tissue cryopreservation (OTC). None of the patients had received exogenous gonadotrophins prior to the procedure. Immature oocytes released from small antral follicles were collected in connection with isolation of the cortex for OTC. The oocytes' maturation stage and the morphological characteristics of the cytoplasm, zona pellucida, perivitelline space and first polar body were assessed after in-vitro maturation (IVM). RESULTS: A total of 1649 immature oocytes were collected: 30% of oocytes matured to the metaphase II (MII) stage after IVM, while metaphase I (MI), germinal vesicle and degenerated oocytes accounted for 20%, 24% and 26%, respectively. The percentages of oocytes without any dysmorphisms were 53%, 92%, and 97% for the MII, MI and germinal vesicle stage oocytes, respectively. The most frequently observed dysmorphisms among the MII oocytes were first polar body fragmentation (22%), homogeneously distributed cytoplasmic granularity (16%) and an enlarged perivitelline space (14%). Interestingly, none of the oocytes at any stage had clusters of smooth endoplasmic reticulum (SER). CONCLUSIONS: Morphological dysmorphisms are present among in-vitro-matured oocytes at all maturation stages. The incidence of dysmorphisms increases as maturation progresses. The most frequent dysmorphism among MII oocytes after IVM was fragmentation of the first polar body. Clusters of SER were not observed in oocytes from unstimulated patients.

Selection of competent oocytes by morphological criteria for assisted reproductive technologies.

Invasive and noninvasive methods are commonly used to select developmentally competent oocytes that can improve the take-home baby rates in assisted reproductive technology (ART) centers. One of the noninvasive methods conventionally utilized to determine competent oocytes is the morphological analysis of cumulus complex, first polar body, zona pellucida, perivitelline space, meiotic spindle, and ooplasm. Successful fertilization, early embryo development, uterine implantation, and healthy pregnancy depend on the quality of oocytes, and morphological evaluation is one of the options used to predict quality levels. In this review, the morphological criteria being utilized in certain ART centers are comprehensively evaluated with special references to their predictive values and potential contributions to selecting high-quality oocytes.

Effect of oocyte morphology on post-warming survival and embryo development in vitrified autologous oocytes.

RESEARCH QUESTION: Does the presence of dysmorphisms affect post-warming survival and embryo development in vitrified autologous oocytes? DESIGN: A retrospective study comparing post-warming survival, fertilization and embryo development between morphologically normal (n = 269) and dysmorphic oocytes (n = 147). RESULTS: The survival rate was 81.4% in the morphologically normal oocytes and 87.1% in the dysmorphic oocyte group (OR 1.53; 95% CI 0.86 to 2.72). The fertilization rate was 69.9 versus 66.4% (OR 0.85; 95% CI 0.53 to 1.36), the proportion of good-quality embryos on day 3 was 30.3% versus 32.0% (OR 1.08; 95% CI 0.59 to 1.97) and the blastocyst formation rate was 54.5% versus 60.5% (OR 1.27; 95% CI 0.60 to 2.72) for the morphologically normal and the dysmorphic oocytes group, respectively. No statistical differences were found when the number and type of dysmorphism were analysed. CONCLUSION: Oocyte dysmorphisms did not seem to affect survival, fertilization and embryo development in vitrified autologous oocytes, and yielded comparable results to the morphologically normal oocytes.

Acquisition of developmental competence and in vitro growth culture of bovine oocytes.

Recently, the demand of transferable embryos in cattle industry is increasing, and the number of embryos produced in vitro is also increasing in the world. Although oocytes are collected from individual elite cattle by ovum-pick up (OPU) and used for in vitro production (IVP) of embryos, the cattle are mono-ovulatory animal. It means that most of oocytes collected from ovaries are destined to degenerate. To improve the IVP efficiency, we should predict the developmental competence of oocytes correctly and culture them by the suitable way. In addition, in vitro production of bovine oocytes by in vitro growth (IVG) culture system will become a candidate of supply source of oocytes for IVP. If we can produce high competent oocytes by IVG, IVP efficiency will be improved and the genetic improvement of cattle will be dramatically accelerated. In the review, I introduce our researches related to oocyte morphology, the developmental competence, and the production of oocytes having high developmental competence by IVG culture.

Detrimental effects of endometriosis on oocyte morphology in intracytoplasmic sperm injection cycles: a retrospective cohort study.

While an association can be addressed among endometriosis and subfertility, the causal relationship has not been elucidated yet. Impaired oocyte quality in endometriosis patients has been accused for the unsuccessful outcomes of assisted reproductive techniques. There are limited studies in literature evaluated association between endometriosis and oocyte morphology. We conducted this retrospective study to evaluate whether morphological abnormalities of oocytes are more common in women with endometriosis than women with diagnosis of male factor infertility as a source of healthy oocytes. Totally 1568 oocytes, 775 (49.4%) in endometriosis groups and 793 (50.6%) in control group were evaluated for morphological parameters before ICSI cycles. Abnormal oocyte morphology was detected in 352 (22.4%) of 1568 oocytes. Of the abnormal oocytes, 208 (59.1%) were in endometriosis group and 144 (40.9%) in control group (p < .001). The following dysmorphisms were significantly higher in oocytes retrieved from endometriosis group: dark cytoplasm; dark, large or thin zona pellucida; and flat or fragmented polar body (p < .05 for all). When morphological parameters for oocytes of endometriosis patients evaluated, the oocyte defects has increased significantly in endometriosis patients. These findings are thought to be useful to clarify the subfertility in endometriosis patient, which needs to be confirmed with further studies.

Cytoplasmic abnormalities of mature oocytes have a significant effect on fertilization in Bologna poor responders

Background/aim: We aimed to investigate whether oocyte morphologic abnormalities affected cycle outcome in poor responder infertile women who fulfilled the Bologna criteria. Materials and methods: Data were obtained from infertile couples who underwent ICSI and embryo transfer at the Zeynep Kamil Maternity and Children's Health Training and Research Hospital Assisted Reproduction Unit in Istanbul, Turkey. They were allocated to two groups: Group A, poor responders, and Group B, normal responders. All morphological abnormalities of oocytes retrieved were reviewed and grouped as cytoplasmic abnormalities or extracytoplasmic abnormalities. All morphological features were compared between the poor and normal responder groups. ICSI cycle outcomes were described as biochemical pregnancy, fertilization rate, number of top-quality zygotes, top-quality zygote rate, number of embryos transferred, and number of top-quality embryos transferred. The relation between each morphological feature and ICSI outcomes was investigated in each group. Results: The results showed no difference between the groups in terms of morphological features of oocytes. The relation between ICSI cycle outcomes and each oocyte morphological feature was compared in the poor and normal responder groups. Presence of cytoplasmic morphological abnormality was found to significantly correlate with the fertilization rate (P = 0.019) in poor responders. Conclusion: Our data show that oocyte cytoplasmic abnormalities significantly reduce fertilization achievement in poor responders.

Oocyte competence in in vitro fertilization and intracytoplasmic sperm injection patients suffering from endometriosis and its possible association with subsequent treatment outcome: a matched case-control study.

INTRODUCTION: Endometriosis affects up to 15% of women of reproductive age. There is an obvious lack of studies dealing with morphological parameters of oocyte morphology in endometriosis patients in assisted reproduction. One aim of the study is to describe oocyte morphology in patients undergoing intracytoplasmic sperm injection suffering from endometriosis. In addition, the impact of endometriosis on in vitro fertilization results is analyzed. Both in vitro fertilization and intracytoplasmic sperm injection patients are then matched with an endometriosis-free control group for highlighting the possible association of endometriosis with pregnancy outcome. MATERIAL AND METHODS: Oocyte morphology of endometriosis patients was assessed in two groups. Both study group and control group consisted of 129 in vitro fertilization/intracytoplasmic sperm injection cycles each. Patients were matched according to anti-Müllerian hormone, female age, previous treatment cycles, and method of fertilization. Endometriosis was graded according to the revised American Society for Reproductive Medicine guidelines of 1997. RESULTS: Patients with endometriosis had a significantly lower rate of mature oocytes (p < 0.03) and morphologically normal oocytes (p < 0.001). In particular, brownish oocytes (p < 0.009; stage I-IV) and the presence of refractile bodies (p < 0.001; stage IV) were found to be increased. Endometriosis stage IV was associated with significantly worse-quality oocytes than stages I-III (p < 0.01). Fertilization was significantly reduced in conventional in vitro fertilization but not in intracytoplasmic sperm injection (p < 0.03). This was due to lower fertilization rates in stage III-IV endometriosis compared with stage I-II (p < 0.04). No difference was observed with respect to rates of implantation, clinical pregnancy, miscarriage, live birth, and malformation. CONCLUSIONS: Endometriosis patients, in particular those with severe endometriosis, present lower-quality oocytes. Once fertilized, no impairment of further preimplantation embryo development and pregnancy outcome right up to healthy live birth rate has to be expected.

Oocyte morphology and embryo morphokinetics in an intra-cytoplasmic sperm injection programme. Is there a relationship?

The aim was to investigate the relationship between the morphological parameters of metaphase II (MII) oocytes with morphokinetic variables of embryos following an intra-cytoplasmic sperm injection (ICSI) procedure. Morphokinetic behaviour and abnormal cleavage patterns of 334 zygotes were analyzed using time-lapse monitoring (TLM). In addition, oocyte morphology was assessed in relation to embryo morphokinetic (absolute time point, including time to second polar body (PB) extrusion (ESPB), pronuclei (PN) appearance (PNA), PN fading (PNF), time to 2-cells (t2), 3c (t3), 4c (t4), 5c (t5), 6c (t6), 7c (t7), 8c (t8) and relative timing parameters (S1, S2, CC2 and CC3). Also, cleavage patterns (uneven blastomeres, reverse, direct and arbitrary) were assessed. The data showed that 79% of the normal fertilized oocytes had at least one abnormal morphological characteristic. Intra-cytoplasmic abnormalities were observed in 12% of the oocytes. Also, extra-cytoplasmic abnormalities were noticed in 29%, while combined intra- and extra-cytoplasmic abnormalities were responsible for the remaining 38% of the oocytes. Nearly all cleavage and interval times, except extrusion of the ESPB time (P = 0.003), were similar between normal and abnormal morphologic oocytes (P < 0.05). Moreover, there was significant relationship for oocyte morphology abnormalities and cleavage patterns, including uneven blastomere (P = 0.037), reverse cleavage (RC) (P = 0.0), direct (P = 0.001) and arbitrary cleavages (P = 0.001). Using TLM, the cleavage patterns of embryos were affected by the quality of MII oocytes in the ICSI cycles. So, evaluation of oocyte morphology with subsequent embryo morphokinetics is recommended in assisted reproductive programmes.

Impact of oxygen tension during in vitro maturation: a sibling-oocyte prospective double-blinded study.

OBJECTIVE: To determine whether oxygen (O2) tension (20% vs. 5%) has an impact on oocyte maturation rates and morphology during in vitro maturation (IVM). DESIGN: A prospective, observational, monocentric, sibling-oocyte study. SETTING: University Hospital. PATIENTS: A total of 143 patients who underwent IVM for fertility preservation purposes from November 2016 to April 2021 were analyzed. Patients were included when ≥2 cumulus-oocyte complexes (COCs) were retrieved. The cohort of COCs obtained for each patient was randomly split into two groups: group 20% O2 and group 5% O2. INTERVENTION: Cumulus-oocyte complexes were incubated for 48 hours either under 5% O2 or 20% O2. After 24 and 48 hours of culture, every oocyte was assessed for maturity and morphology, to estimate oocyte quality. Morphology was evaluated considering six parameters (shape, size, ooplasm, perivitelline space, zona pellucida, and polar body characteristics), giving a total oocyte score ranging from -6 to +6. MAIN OUTCOME MEASURES: Maturation rates and total oocyte scores were compared using paired-sample analysis between group 20% O2 and group 5% O2. RESULTS: Patient median age was 31.4 [28.1-35.2] years-old. The mean serum antimüllerian hormone levels and antral follicle count were 3.2 ± 2.3 ng/mL and 27.2 ± 16.0 follicles, respectively. A mean of 10.7 COCs per cycle were retrieved, leading to 6.1 ± 2.4 metaphase II oocytes vitrified (total maturation rate = 57.3%; 991 metaphase II oocytes/1,728 COCs). A total of 864 COCs were included in each group. Oocyte maturation rates were not different between the two groups (group 20% O2: 56.82% vs. group 5% O2: 57.87%, respectively). Regarding oocyte morphology, the mean total oocyte score was significantly higher in group 5% O2 compared with group 20% O2 (3.44 ± 1.26 vs. 3.16 ± 1.32, P=.014). CONCLUSION: As culture under low O2 tension (5% O2) improves oocyte morphology IVM, our results suggest that culture under hypoxia should be standardized. Additional studies are warranted to assess the impact of O2 tension on oocyte maturation and the benefit of IVM under low O2 tension for embryo culture after utilization of frozen material.

Morphological assessment of oocyte quality during assisted reproductive technology cycle.

Following the advancement of medically assisted reproduction (MAR) technology, and the rationale to extend the culture to the blastocyst stage, performing elective single embryo transfer (eSET), gamete quality and assessment have acquired large relevance in ART. Embryo quality is strictly correlated with gametes quality and culture conditions. Oocyte maturity assessment is therefore imperative for fertilization and embryo evolution. Mature oocytes at the metaphase II stage result in a higher fertilization rate compared to immature oocytes. Indeed, oocyte morphology evaluation represents an important and challenging task that may serve as a valuable prognostic tool for future embryo development and implantation potential. Different grading systems have been reported to assess human embryos, however, in many cases, it is still a major challenge to select the single embryo to transfer with the highest implantation potential. Further, eSET has conferred a challenge to embryologists, who must try to enhance embryo culture and selection to provide an adequate success rate, whilst reducing the overall number of embryos transferred. Above the standard morphological assessment, there are several invasive or non-invasive approaches for embryo selection such as preimplantation genetic testing, time-lapse technology, proteomics and metabolomics, as well as oxygen utilization and analysis of oxidative stress in culture medium. This short review is not designed to be a comprehensive review of all possible features that may influence oocyte quality. It does give, however, a brief overview and describes the prognostic value of the morphological characteristics of human oocytes on their developmental capacity following ART treatments.

Exploring the Impact of Controlled Ovarian Stimulation and Non-Invasive Oocyte Assessment in ART Treatments.

Invasive and noninvasive features are normally applied to select developmentally competent oocytes and embryos that can increase the take-home baby rates in assisted reproductive technology. The noninvasive approach mainly applied to determine oocyte and embryo competence has been, since the early days of IVF, the morphological evaluation of the mature cumulus-oocyte complex at the time of pickup, first polar body, zona pellucida thickness, perivitelline space and cytoplasm appearance. Morphological evaluation of oocyte quality is one of the options used to predict successful fertilization, early embryo development, uterine implantation and the capacity of an embryo to generate a healthy pregnancy to term. Thus, this paper aims to provide an analytical revision of the current literature relating to the correlation between ovarian stimulation procedures and oocyte/embryo quality. In detail, several aspects of oocyte quality such as morphological features, oocyte competence and its surrounding environment will be discussed. In addition, the main noninvasive features as well as novel approaches to biomechanical parameters of oocytes that might be correlated with the competence of embryos to produce a healthy pregnancy and live birth will be illustrated.

Human Oocyte Morphology and Outcomes of Infertility Treatment: a Systematic Review.

Oocyte morphology assessment is easy to implement in any laboratory with possible quality grading prior to fertilization. At present, comprehensive oocyte morphology scoring is not performed as a routine procedure. However, it may augment chances for successful treatment outcomes if a correlation with certain dysmorphisms can be proven. In order to determine a correlation between oocyte morphology and treatment outcome, we performed a systematic search in PubMed and Cochrane Controlled Trials Register following PRISMA guidelines. A total of 52 articles out of 6,755 search results met the inclusion criteria. Dark colour of the cytoplasm (observed with an incidence rate of 7%), homogeneous granularity of the cytoplasm (19%) and ovoid shape of oocytes (7%) appeared to have no influence on treatment outcome. Abnormalities such as refractile bodies (10%), fragmented first polar body (37%), dark zona pellucida (9%), enlarged perivitelline space (18%) and debris in it (21%) are likely to affect the treatment outcome to some extent. Finally, cytoplasmic vacuoles (4%), centrally located cytoplasmic granularity (12%) and clusters of smooth endoplasmic reticulum (4%) negatively impact infertility treatment outcomes. Nonetheless, morphological assessment is informative rather than predictive. Adding oocyte morphology to the artificial intelligence (AI)-driven selection process may improve the precision of the algorithms. Oocyte morphology assessment can be especially useful in oocyte donation cycles, during oocyte freezing for fertility preservation and finally, objective oocyte scoring can be important in cases of very poor treatment outcome as a tool for explanation of results to the patient.

Metaphase II (MII) human oocytes with smooth endoplasmic reticulum clusters do not affect blastocyst euploid rate.

OBJECTIVE: To investigate whether the rate of euploidy and pregnancy outcomes are affected by smooth endoplasmic reticulum clusters (SERc) and other metaphase II human oocyte dysmorphisms. MATERIALS AND METHODS: Retrospective analysis of the morphologies of metaphase II (MII) human oocytes, which had developed into 590 biopsied blastocysts derived from 109 patients that received preimplantation genetic testing for aneuploidies (PGT-A) cycles between March 2013 and December 2017. The euploid rate of blastocysts that originated from morphologically abnormal or normal oocytes were analyzed. The chromosome status of the blastocysts was determined and analyzed by array comparative genomic hybridization (aCGH) or next generation sequencing (NGS) following trophectoderm biopsy. RESULTS: According to the odds ratios obtained for each oocyte morphotype, no statistically significant relationship was found between oocyte dysmorphisms and euploid rate. Specifically, although SERc-positive oocytes had a higher rate of arrest at two pronuclei, or 2 PN (26.7% vs. 19.4%, p > 0.05), the blastocyst formation rate was not affected as compared with SERc-negative oocytes (40.0% vs. 38.6%, p > 0.05). Among nine euploid embryos derived from oocytes with SERc, three single euploid embryo transfers were performed, of which one resulted in blighted ovum, and two resulted in the births of two healthy, singleton term babies. CONCLUSION: The results presented here suggest that oocyte dysmorphisms do not affect the euploidy rate of the blastocyst. The occurrence of SERc in the oocyte does not seem to impair the developing blastocyst nor does it interfere with good embryo formation rate and euploid rate. Thus, the embryos derived from SERc-positive oocytes could still be considered for embryo transfer if there are no other embryos available.

Oocyte Morphology and Reproductive Outcomes - Case Report and Literature Review.

Oocyte quality could be negatively affected by many factors including smoking, alcohol consumption, obesity, woman's age, endometriosis and controlled ovarian stimulation (COS), during assisted reproductive technology (ART), in addition to genetic factors, such as hormone receptor polymorphisms, for example. We know that the increase in the reactive oxygen species (ROS) due to systemic disorders causes biochemical and morphological changes to the oocytes, interfering with their quality. The oocyte dysmorphism can be expressed through intra and/or extra cytoplasmic changes. In general, the size and number of oocytes' morphological abnormalities are directly related to preimplantation development failure. This case report is based on four in vitro fertilization (IVF) cycles performed by a patient with oocyte dysmorphism in all oocytes captured. The literature review on this topic aims to relate the characteristics of the oocytes, presented in the case report, with research results about the quality and morphology of the oocytes.