Effect of oocyte dysmorphisms on intracytoplasmic sperm injection cycle outcomes in normal ovarian responders

The Istanbul Consensus update: a revised ESHRE/ALPHA consensus on oocyte and embryo static and dynamic morphological assessment† ‡

This European Society of Human Reproduction and Embryology (ESHRE)/Alpha Scientists in Reproductive Medicine (ALPHA) consensus document provides several novel recommendations to assess oocyte and embryo morphology and rank embryos for transfer. A previous ALPHA/ESHRE consensus on oocyte and embryo morphological assessment was published in 2011. After more than a decade, and the integration of time-lapse technology into embryo culture and assessment, a thorough review and update was needed. A working group consisting of ALPHA members and ESHRE Special interest group of Embryology members formulated recommendations on oocyte and embryo assessment. The working group included 17 internationally recognized experts with extensive experience in clinical embryology. Seven members represented ALPHA and eight members represented ESHRE, along with two methodological experts from the ESHRE central office. Based on a systematic literature search and discussion of existing evidence, the recommendations of the Istanbul Consensus (2011) were reassessed and, where appropriate, updated based on consensus within the working group. A stakeholder review was organized after the updated draft was finalized. The final version was approved by the working group, the ALPHA Executive Committee and the ESHRE Executive Committee. This updated consensus paper provides 20 recommendations focused on the timeline of preimplantation developmental events and morphological criteria for oocyte, zygote and embryo assessment. Based on the duration of embryo culture, recommendations are given on the frequency and timing of assessments to ensure consistency and effectiveness. Several criteria relevant to oocyte and embryo morphology have not been well studied, leading to either a recommendation against their use for grading or for their use in ranking rather than grading. Future updates may require further revision of these recommendations. This document provides embryologists with advice on best practices when assessing oocyte and embryo quality based on the most recent evidence.

The Istanbul consensus update: a revised ESHRE/ALPHA consensus on oocyte and embryo static and dynamic morphological assessment†,‡

STUDY QUESTION

What are the current recommended criteria for morphological assessment of oocytes, zygotes, and embryos?

SUMMARY ANSWER

The present ESHRE/Alpha Scientists in Reproductive Medicine consensus document provides several novel recommendations to assess oocyte and embryo morphology and rank embryos for transfer.

WHAT IS KNOWN ALREADY

A previous Alpha Scientists in Reproductive Medicine/ESHRE consensus on oocyte and embryo morphological assessment was published in 2011. After more than a decade, and the integration of time-lapse technology into embryo culture and assessment, a thorough review and update was needed.

STUDY DESIGN, SIZE, DURATION

A working group consisting of Alpha Scientists in Reproductive Medicine executive committee members and ESHRE Special interest group of Embryology members formulated recommendations on oocyte and embryo assessment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The working group included 17 internationally recognized experts with extensive experience in clinical embryology. Seven members represented Alpha Scientists in Reproductive Medicine and eight members represented ESHRE, along with to two methodological experts from the ESHRE central office. Based on a systematic literature search and discussion of existing evidence, the recommendations of the Istanbul Consensus (2011) were reassessed and, where appropriate, updated based on consensus within the working group. A stakeholder review was organized after the updated draft was finalized. The final version was approved by the working group, the Alpha executive committee and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This updated consensus paper provides 20 recommendations focused on the timeline of preimplantation developmental events and morphological criteria for oocyte, zygote, and embryo assessment. Based on duration of embryo culture, recommendations are given on the frequency and timing of assessments to ensure consistency and effectiveness.

LIMITATIONS, REASONS FOR CAUTION

Several criteria relevant to oocyte and embryo morphology have not been well studied, leading to either a recommendation against their use for grading or for their use in ranking rather than grading. Future updates may require further revision of these recommendations.

WIDER IMPLICATIONS OF THE FINDINGS

This document provides embryologists with advice on best practices when assessing oocyte and embryo quality based on the most recent evidence.

STUDY FUNDING/COMPETING INTEREST(S)

The consensus meeting and writing of the paper were supported by funds from ESHRE and Alpha Scientists in Reproductive Medicine. The working group members did not receive any payment. G.C. declared payments or honoraria for lectures from Gedeon Richter and Cooper Surgical. A.C. declared text book royalties (Mastering Clinical Embryology, published 2024), consulting fees from Cooper Surgical, Gedeon Richter and TMRW Life Sciences, honoraria for lectures from Merck, Ferring, and Gedeon Richter, and participation in the HFEA Scientific Advances Committee; she also disclosed being treasurer and vice-president of Alpha Scientists in Reproductive Medicine, a shareholder in Care Fertility Limited and Fertile Mind Limited, and having stock options in TMRW Life Sciences and U-Ploid Biotechnology Ltd. L.R. declared consulting fees from Organon, payments or honoraria for lectures from Merck, Organon, IBSA, Finox, Geden Richter, Origio, Organon, Ferring, Fundation IVI; she also disclosed being a member of the Advisory Scientific Board of IVIRMA (Paid) and a member of the Advisory Scientific Board of Nterilizer (unpaid). I.S. declared payments or honoraria for lectures from Vitrolife and Cooper Surgical, and stock options from Alife Health. M.A. declared payments or honoraria for lectures from Vitrolife and support for attending meetings from Vitrolife and Cooper Surgical (both unrelated to this manuscript). The other authors have no conflicts of interest to declare.

DISCLAIMER

This Good Practice Recommendations (GPRs) document represents the consensus views of the members of this working group based on the scientific evidence available at the time of the meeting. GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or be deemed inclusive of all proper methods of care or be exclusive of other methods of care reasonably directed to obtaining the same results. They do not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type.

Quality of IVM ovarian tissue oocytes: impact of clinical, demographic, and laboratory factors

PURPOSE

To determine how clinical, demographic, and laboratory characteristics influence ovarian tissue oocyte quality.

METHODS

Immature cumulus-oocyte complexes were isolated from removed ovaries and cultured for 48-52 h in either monophasic standard or biphasic CAPA media for fertility preservation. A total of 355 MII oocytes from 53 patients were described for intracytoplasmic and extracytoplasmic anomalies. Multiple clinical, laboratory, and demographic characteristics were analyzed. Statistically significant differences between independent groups in qualitative variables were identified using Pearson's χ2 and Fisher's exact tests. The diagnostic value of quantitative variables was assessed using the ROC curve analysis. Factors associated with the development of dysmorphism, taking patient age into account, were identified using the binary logistic regression analysis.

RESULTS

Dysmorphisms were observed in 245 oocytes (69.0%), with a median number of dysmorphisms of 2. Oocyte dysmorphisms were found to be 2.211 times more likely to be detected in patients with ovarian cancer, while the presence of dark-colored cytoplasm was associated with gynecologic surgery in the anamnesis (p = 0.002; OR 16.652; 95% CI, 1.977-140.237; Cramer's V 0.187). Small polar bodies developed 2.717 times more often (95% CI, 1.195-6.18) in patients older than 35. In the case of ovarian transportation on ice at 4 ℃, the chances of development of cytoplasmic granularity increased 2.569 times (95% CI, 1.301-5.179). The use of biphasic CAPA IVM media contributed to a decrease in the probability of large polar body formation (p = 0.034) compared to the standard monophasic IVM media.

CONCLUSIONS

Both patients' characteristics and laboratory parameters have an impact on the quality of IVM ovarian tissue oocytes.

In Vitro Fertilization (IVF) Outcomes in Patients With Endometriosis Compared to Patients With Tubal Factor Infertility in Indonesia: A Retrospective Study

BACKGROUND

Endometriosis is a disease characterized by dysmenorrhea, chronic pelvic pain, and infertility. The pathogenesis of endometriosis and its relationship to infertility are still not fully understood. In vitro fertilization (IVF) is considered an effective treatment for patients with endometriosis-associated infertility. This study compared the pregnancy rates of endometriosis patients who underwent IVF with those of patients with tubal obstruction.

METHODS

This was a retrospective cross-sectional study of 225 patients with endometriosis and tubal factor infertility who underwent IVF at Yasmin Clinic, Dr. Cipto Mangunkusumo National General Hospital, Jakarta, Indonesia, between January 2013 and August 2021. Demographic data, anti-Mullerian hormone (AMH) levels, the initial and total dose of recombinant follicle stimulating hormone (rFSH), the total dose of recombinant luteinizing hormone (rLH), stimulation duration, oocyte maturation rates, fertilization rates, embryo cleavage rates, and pregnancy rates (biochemical, clinical and ongoing) were obtained.

RESULTS

AMH level, number of oocytes retrieved, and embryo cleavage rates were significantly lower in the endometriosis group. Initial and total doses of rFSH and total dose of rLH were higher, and the duration of stimulation was longer in the endometriosis group compared to the tubal factor group. In the endometriosis group, the biochemical (47.3% vs. 52.7%, p=0.375), clinical (43.1% vs. 56.9%, p=0.215), and ongoing (45.5% vs. 54.5%, p=0.511) pregnancy rates were lower than those in the tubal factor group. However, there were no statistically significant differences between the two groups. There was no significant difference in pregnancy rates between the short antagonist and ultra-long protocols (three months of downregulation). From multivariate analysis, only rLH supplementation was found to be significantly related to pregnancy outcomes in patients with endometriosis.

CONCLUSION

AMH levels, number of oocytes retrieved, and embryo cleavage rates were lower in patients with endometriosis. However, pregnancy rates were not significantly different from patients with tubal factors. Supplementation with rLH may improve pregnancy rates in patients with endometriosis who have undergone IVF programs.

The impact of severe oligozoospermia on morphokinetic embryo development in low-prognosis patients according to the Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number criteria: an analysis of 10,366 injected oocytes

OBJECTIVE

To study whether severe male factor infertility (SMF), reflected by oligozoospermia, impacts embryo morphokinetic behavior in low-prognosis women as stratified by the Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number (POSEIDON) criteria.

DESIGN

Cohort study.

SETTING

Private university-affiliated in vitro fertilization center.

PATIENT(S)

A total of 10,366 injected oocytes from 2,272 women who underwent intracytoplasmic sperm injection cycles between March 2019 and April 2022.

INTERVENTION(S)

Patients were divided into 8 groups according to the POSEIDON criteria (1-4) and the presence or absence of SMF. A control group of normoresponder patients was included. Kinetic markers from the point of insemination were recorded in the EmbryoScope incubator.

MAIN OUTCOME MEASURE(S)

Morphokinetic milestones and intracytoplasmic sperm injection clinical outcomes.

RESULT(S)

Embryos from patients in the POSEIDON 1 group showed significantly slower timing to pronuclear appearance, timing to pronuclear fading (tPNf), timing to 2 (t2), 3 (t3), 4 (t4), 6 (t6), and 7 (t7) cells than those from the control group. Known Implantation Diagnosis Score ranking was significantly different between the SMF and non-SMF (nSMF) subgroups in both POSEIDON 1 as well as control groups. Embryos from patients in the POSEIDON 2 group showed significantly slower timing to pronuclear appearance, t4, t6, t7, timing to 8 cells (t8), and timing to morulae than those from the control group. Embryos in the POSEIDON 2 SMF subgroup took longer than those in the POSEIDON 2 nSMF subgroup and those in both control subgroups to achieve tPNf, t2, t3, timing to 5 cells (t5), timing to start blastulation, and timing to blastulation. Known Implantation Diagnosis Score ranking was significantly different between the SMF and nSMF subgroups in both POSEIDON 2 as well as control groups. Embryos from patients in the POSEIDON 3 group showed significantly slower t8 and duration of the second cell cycle (t3-t2) than those from the control group. Known Implantation Diagnosis Score ranking was significantly different across the subgroups. Embryos derived from patients in the POSEIDON 4 group showed significantly slower tPNf, t2, t3, t4, t5, t6, t7, t8, timing to complete t4-t3 synchronous divisions, and timing to complete t8-t5 synchronous divisions than those from the control group. Known Implantation Diagnosis Score ranking was significantly different between the SMF and nSMF subgroups in both POSEIDON 4 as well as control groups. Irrespective of sperm quality, clinical outcomes significantly improved in the control subgroups compared with those in the POSEIDON 2 and 4 subgroups.

CONCLUSION(S)

Embryos in the SMF groups presented lower Known Implantation Diagnosis Score ranking than those in the nSMF groups in both POSEIDON 1-4 and control groups, suggesting that cumulative differences result in worse morphokinetic development when the algorithm is used.

Human metaphase II oocytes with narrow perivitelline space have poor fertilization, developmental, and pregnancy potentials

PURPOSE

To analyze the fertilization, developmental, and pregnancy potentials in oocytes with narrow perivitelline space.

METHODS

Perivitelline space (PVS) of oocytes was evaluated at the time of ICSI, and those without sufficient PVS were judged as oocytes with narrow PVS (NPVS oocytes), and those with sufficient PVS formation were judged as oocytes with non-narrow PVS (non-NPVS oocytes). The analysis included 634 NPVS oocytes from 278 cycles and 12,121 non-NPVS oocytes from 1698 cycles. The fertilization and developmental potentials of NPVS and non-NPVS oocytes were compared by calculating odds ratios using a mixed-effects logistic regression model. We also compared the embryo transfer outcomes of those used for single vitrified-warmed blastocyst transfer after developing into the blastocyst stage.

RESULTS

NPVS oocytes had higher odds ratios for degeneration (adjusted odds ratio [aOR], 1.555; 95% confidence interval [CI], 1.096-2.206; p = 0.0133) and 0PN (aOR, 1.387; 95% CI, 1.083-1.775; p = 0.0095), resulting in a lower 2PN rate (aOR, 0.761; 95% CI, 0.623-0.929; p = 0.0072). Even embryos with confirmed 2PN had lower odds ratios for cleavage (aOR, 0.501; 95% CI, 0.294-0.853; p = 0.0109) and blastocyst development (Gardner criteria; CC-AA) rates (aOR, 0.612; 95% CI, 0.476-0.788; p = 0.0001). Blastocysts developed from NPVS oocytes had significantly lower odds ratios for clinical pregnancy (aOR, 0.435; 95% CI, 0.222-0.854; p = 0.0156) than those developed from non-NPVS oocytes.

CONCLUSIONS

Oocytes with NPVS have low fertilization and developmental potential, as well as low likelihood of pregnancy.

Cytoplasmic granules in bovine oocytes do not affect embryonic or fetal development

Oocyte cytoplasmic evaluation is based on homogeneity and granular appearance. Our study investigated if a granular cytoplasm, highly heterogeneous, would affect oocyte competence in bovine. In two experiments, bovine cumulus-oocyte complexes (COCs) with homogeneous cytoplasm (control, CC) and granulated cytoplasm (granular, GC) were selected from a regular pool of COCs. Experiment 1 was performed with slaughterhouse ovaries, and Experiment 2 was carried out in Girolando COCs obtained from ovum pick-up. Granular oocytes had higher caspase 3 levels (66.17 ± 11.61 vs 172.08 ± 16.95, P < 0.01) and similar GAP junction activity (5.64 ± 0.45 vs 6.29 ± 0.29). ZAR1 relative mRNA amount was lower in granular oocytes (178.27 ± 151.63 vs 0.89 ± 0.89, P = 0.01) and no effect was detected for MATER, PPP2R1A, ENY2, IGF2R, and BMP15 genes. Despite molecular differences, no detrimental effect was detected on oocyte competence in GC oocytes. Cleavage (Experiment 1: 59.52 ± 7.21% vs 59.79 ± 6.10% and Experiment 2: 68.88 ± 4.82 vs 74.41 ± 5.89%) and blastocyst (Experiment 1: 29.28 ± 4.14% vs 23.15 ± 2.96% and Experiment 2: 21.11 ± 3.28% vs 21.02 ± 6.08%) rates were similar between CC and GC (Experiments 1 and 2, respectively). Post-transfer embryo development revealed that pregnancy (CC: 24.27 ± 9.70% vs GC: 26.31 ± 7.23%) and calving (23.68% vs 33.33%) rates and fetal growth were not affected by the presence of cytoplasmic granules. Our results demonstrated that oocytes with granular cytoplasm present equivalent efficiency for IVF and calf production compared with homogenous cytoplasm oocytes. This could be observed through similar cleavage, blastocyst rates, and fetal growth development. In addition to differences in oocyte gene expression related to oocyte quality, it seems not to affect oocyte developmental competence.

The ultrastructural nature of human oocytes' cytoplasmic abnormalities and the role of cytoskeleton dysfunction

OBJECTIVE

To investigate the structural bases of human oocytes' cytoplasmic abnormalities and the causative mechanism of their emergence. Knowledge of an abnormal oocyte's intracellular organization is vital to establishing reliable criteria for clinical evaluation of oocyte morphology.

DESIGN

Laboratory-based study on experimental material provided by a private assisted reproduction clinic.

SETTING

University laboratory and imaging center.

PATIENTS

A total of 105 women undergoing hormonal stimulation for in vitro fertilization (IVF) donated their spare oocytes for this study.

INTERVENTIONS

Transmission electron microscopy (TEM) was used to analyze the fine morphology of 22 dysmorphic IVF oocytes exhibiting different types of cytoplasmic irregularities, namely, refractile bodies; centrally located cytoplasmic granularity (CLCG); smooth endoplasmic reticulum (SER) disc; and vacuoles. A total of 133 immature oocytes were exposed to cytoskeleton-targeting compounds or matured in control conditions, and their morphology was examined using fluorescent and electron microscopy.

MAIN OUTCOME MEASURES

The ultrastructural morphology of dysmorphic oocytes was analyzed. Drug-treated oocytes had their maturation efficiency, chromosome-microtubule configurations, and fine intracellular morphology examined.

RESULTS

TEM revealed ultrastructural characteristics of common oocyte aberrations and indicated that excessive organelle clustering was the underlying cause of 2 of the studied morphotypes. Inhibition experiments showed that disruption of actin, not microtubules, allows for inordinate aggregation of subcellular structures, resembling the ultrastructural pattern seen in morphologically abnormal oocytes retrieved in IVF cycles. These results imply that actin serves as a regulator of organelle distribution during human oocyte maturation.

CONCLUSION

The ultrastructural analogy between dysmorphic oocytes and oocytes, in which actin network integrity was perturbed, suggests that dysfunction of the actin cytoskeleton might be implicated in generating common cytoplasmic aberrations. Knowledge of human oocytes' inner workings and the origin of morphological abnormalities is a step forward to a more objective oocyte quality assessment in IVF practice.

Evaluation of the relationship between vitamin D levels with oocyte quality in breast cancer women: a cross-sectional study

Recent evidence suggests that vitamin D deficiency could play an important role in the development of non-skeletal diseases, including cancer. Vitamin D also affects the function of the reproductive system. In the present study, the relationship between 25(OH)D levels with oocyte quality in Breast Cancer (BC) women and control group have been investigated. After initial evaluations, ovarian stimulation began with the GnRH antagonist protocol in the BC group (N = 16) and control group (N = 16). The serum and follicular fluid (FF) 25(OH)D levels were measured at the time of oocyte retrieval and their relationship to oocyte quality was examined. The mean levels of serum and FF 25(OH)D in BC women were significantly lower than in the control group (22.26 ± 7.98 vs. 29.61 ± 9.12, P = 0.02, 21.65 ± 7.59 vs. 28.00 ± 9.05, P = 0.04, respectively). There was a significant correlation between the levels of 25(OH)D in FF and serum in BC women (r = 0.873, P < 0.001). But there was no correlation between the serum or FF 25(OH)D levels with the parameters related to oocytes (P > 0.05). In the BC women, the number of dysmorph and highly dysmorph oocytes was higher than in the control group (P < 0.001). Women with BC referring to infertility centers for fertility preservation are more likely to be deficient in serum 25(OH)D level; this subsequently affects the FF 25(OH)D level. However, serum and FF 25(OH)D levels may not be suitable indicators for examining maturity and quality of oocytes in terms of morphology in BC women, and the poor morphological quality of oocytes in BC women may be due to other factors.

Unique Deep Radiomic Signature Shows NMN Treatment Reverses Morphology of Oocytes from Aged Mice

The purpose of this study is to develop a deep radiomic signature based on an artificial intelligence (AI) model. This radiomic signature identifies oocyte morphological changes corresponding to reproductive aging in bright field images captured by optical light microscopy. Oocytes were collected from three mice groups: young (4- to 5-week-old) C57BL/6J female mice, aged (12-month-old) mice, and aged mice treated with the NAD+ precursor nicotinamide mononucleotide (NMN), a treatment recently shown to rejuvenate aspects of fertility in aged mice. We applied deep learning, swarm intelligence, and discriminative analysis to images of mouse oocytes taken by bright field microscopy to identify a highly informative deep radiomic signature (DRS) of oocyte morphology. Predictive DRS accuracy was determined by evaluating sensitivity, specificity, and cross-validation, and was visualized using scatter plots of the data associated with three groups: Young, old and Old + NMN. DRS could successfully distinguish morphological changes in oocytes associated with maternal age with 92% accuracy (AUC~1), reflecting this decline in oocyte quality. We then employed the DRS to evaluate the impact of the treatment of reproductively aged mice with NMN. The DRS signature classified 60% of oocytes from NMN-treated aged mice as having a ‘young’ morphology. In conclusion, the DRS signature developed in this study was successfully able to detect aging-related oocyte morphological changes. The significance of our approach is that DRS applied to bright field oocyte images will allow us to distinguish and select oocytes originally affected by reproductive aging and whose quality has been successfully restored by the NMN therapy.

Multispectral autofluorescence characteristics of reproductive aging in old and young mouse oocytes

Increasing age has a major detrimental impact on female fertility, which, with an ageing population, has major sociological implications. This impact is primarily mediated through deteriorating quality of the oocyte. Deteriorating oocyte quality with biological age is the greatest rate-limiting factor to female fertility. Here we have used label-free, non-invasive multi-spectral imaging to identify unique autofluorescence profiles of oocytes from young and aged animals. Discriminant analysis demonstrated that young oocytes have a distinct autofluorescent profile which accurately distinguishes them from aged oocytes. We recently showed that treatment with the nicotinamide adenine dinucleotide (NAD+) precursor nicotinamide mononucleotide (NMN) restored oocyte quality and fertility in aged animals, and when our analysis was applied to oocytes from aged animals treated with NMN, 85% of these oocytes were classified as having the autofluorescent signature of young animals. Spectral unmixing using the Robust Dependent Component Analysis (RoDECA) algorithm demonstrated that NMN treatment altered the metabolic profile of oocytes, increasing free NAD(P)H, protein bound NAD(P)H, redox ratio and the ratio of bound to free NAD(P)H. The frequency of oocytes with simultaneously high NAD(P)H and flavin content was also significantly increased in mice treated with NMN. Young and Aged + NMN oocytes had a smoother spectral distribution, with the distribution of NAD(P)H in young oocytes specifically differing from that of aged oocytes. Identifying the multispectral profile of oocyte autofluorescence during aging could have utility as a non-invasive and sensitive measure of oocyte quality.

Does morphological assessment predict oocyte developmental competence? A systematic review and proposed score

PURPOSE

Does existing scientific literature suggest an impact of oocyte dysmorphisms on biological or clinical outcomes of assisted reproduction treatments?

METHODS

Studies of interest were selected from an initial cohort of 6651 potentially relevant records retrieved. PubMed was systematically searched for peer-reviewed original papers and reviews identified by keywords and medical subject heading (MeSH) terms. The most relevant publications were critically evaluated to identify criteria for oocyte morphological evaluation and IVF outcomes. For each morphological abnormality, we generated an oocyte literature score (OLS) through the following procedure: (a) papers showing a negative, absence of, or positive correlation between a given abnormality and IVF outcome were scored 1, 0, and - 1, respectively; (b) the sum of these scores was expressed as a fraction of all analyzed papers; (c) the obtained fraction was multiplied by 10 and converted into decimal number.

RESULT

We identified eleven different dysmorphisms, of which six were extracytoplasmic (COC, zona pellucida, perivitelline space, polar body 1, shape, giant size) and five intracytoplasmic (vacuoles, refractile bodies, SER clusters, granularity, color). Among the extracytoplasmic dysmorphisms, abnormal morphology of the COC generated an OLS of 8.33, indicating a large prevalence (5/6) of studies associated with a negative outcome. Three intracytoplasmic dysmorphisms (vacuoles, SER clusters, and granularity) produced OLS of 7.14, 7.78, and 6.25, respectively, suggestive of a majority of studies reporting a negative outcome.

CONCLUSION

COC morphology, vacuoles, SER clusters, and granularity produced OLS suggestive of a prevalence of studies reporting a negative outcome.

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.

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.

Follicular GH and IGF1 Levels Are Associated With Oocyte Cohort Quality: A Pilot Study

INTRODUCTION

Oocyte quality contributes to the development of an optimal embryo and thus a successful pregnancy. The objective of this study was to analyse the association between oocyte cohort quality and the follicular levels of growth hormone (GH), insulin-like growth factor 1 (IGF1), 25-hydroxy vitamin D (25OHD), thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4) and antithyroid antibodies, as a function of intracytoplasmic sperm injection (ICSI) outcomes.

MATERIAL AND METHODS

We conducted a prospective comparative pilot study from January 2013 to December 2017. 59 ICSI cycles constituted an abnormal oocyte cohort (n=34 cycles, in which more than 50% of oocytes presented at least one morphological abnormality) and a normal oocyte cohort (n=25 cycles, in which 50% or less of the oocytes presented at least one morphological abnormality). GH, IGF1, 25OHD, TSH, fT3, fT4 and antithyroid antibodies were measured in follicular fluid.

RESULTS

The fertilisation rate was lower in the abnormal oocyte cohort (65.5% vs. 80%, respectively, p=0.012). Oocytes' proportion with at least one abnormality was 79.4% in the abnormal oocyte cohort and 29.0% in the normal oocyte cohort. The mean number of morphological abnormalities per oocyte was significantly higher in the abnormal oocyte cohort. The follicular levels of GH (4.98 vs. 2.75 mIU/L, respectively; p <0.01) and IGF1 (72.1 vs. 54.2 ng/mL, respectively; p=0.05) were higher in the normal oocyte cohort. There was no association with follicular levels of TSH, fT3, fT4, antithyroid antibodies, or 25OHD.

CONCLUSION

Oocyte cohort quality appears to be associated with follicular levels of GH and IGF1.

The impact of letrozole administration on oocyte morphology in breast cancer patients undergoing fertility preservation

Objective:

Patients submitted to oncological fertility preservation with letrozole and gonadotropins seem to present a higher rate of immature oocytes and lower fertilization rates in comparison to infertile patients submitted to IVF cycles with gonadotropins. The aim of this study was to evaluate the influence of letrozole on oocyte morphology in patients with breast cancer submitted to fertility preservation.

Methods:

Retrospective analysis performed at a public tertiary hospital in São Paulo, Brazil. The oocytes were retrieved from patients with breast cancer undergoing fertility preservation (n=69), and from infertile women undergoing in vitro fertilization (n=92). We evaluated 750 oocytes obtained from breast cancer patients submitted to ovarian stimulation with letrozole and gonadotropins, and 699 oocytes from patients without breast cancer submitted to ovarian stimulation for in vitro fertilization with gonadotropins only due to male factor infertility. The mature oocytes retrieved were analyzed for the presence of refractile bodies, ooplasm color and regularity, central granulation degree, cortical granules, zona pellucida staining and regularity, perivitelline space, presence of vacuoles or abnormal smooth-surfaced endoplasmic reticle and oocyte retraction.

Results:

There was a higher incidence of alterations in oocyte morphology in the letrozole group when compared to the control group: increased perivitelline space (p=0.007), irregular zona pellucida (p<0.001), refractile bodies (p<0.001), dark ooplasm (p<0.001), granular ooplasm (p<0.001), irregular ooplasm (p<0.001) and dense central granulation (p<0.001).

Conclusion:

Letrozole is a risk factor for worse oocyte morphology. However, the clinical impact of ovarian stimulation protocol with combined use of gonadotropins and letrozole for fertility preservation remains unclear in this setting. These data underline the importance of establishing the predictive potential of morphological dimorphisms of human oocytes in IVF outcomes.

Double mild stimulation and egg collection in the same cycle for management of poor ovarian responders

PURPOSE

To evaluate the effect of double stimulations during the follicular and luteal phases in women with poor ovarian response (POR) in in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles.

BASIC PROCEDURES

This prospective clinical study was performed in Royan Institute from October 2014 to January 2016. 121 patients were diagnosed as POR on the basis of Bologna criteria were included. Double stimulations were performed during the follicular and luteal phases by Letrozole, Clomid, hMG and GnRH-agonist. The patients' present cycle outcomes were compared with those of the previous cycle results using appropriate statistical tests.

MAIN FINDING

The total of 104 (85.9%) patients completed the stimulation stages. The analysis revealed the number of retrieved oocytes after the first and second stimulations did not differ (P = 0.2); however, the fertilization rate and the number of frozen embryos after the first stimulation were significantly higher than those of in the second stimulation (P < 0.001 and P = 0.03), indicating the better quality of retrieved oocytes after the first stimulation. The mean number of MII oocytes and the fertilization rate after Shanghai protocol were higher than those of the previous antagonist protocol with a substantial trend toward significance (P = 0.06), which can be clinically important. The cancellation rate (33%) due to no ovarian response and no embryo formation was still high in these patients.

PRINCIPAL CONCLUSION

Since the intensity of stimulation in both stages was mild, this protocol can be considered a time-efficient and patient friendly regime; however, more studies are required with emphasis on its cost-effectiveness.

Factors that Influence The Occurrence of Multiple Pregnancies after Intracytoplasmic Injection Cycles with Two or Three Fresh Embryo Transfers

Background

Multiple pregnancies are an important complication of assisted reproductive technology (ART). The present study aims to indentify the risk factors for multiple pregnancies independent of the number of transferred embryos.

MATERIALS AND METHODS

This retrospective study reviewed the medical records of patients who underwent intracytoplasmic sperm injection (ICSI) cycles in Royan Institute between October 2011 and January 2012. We entered 12 factors that affected the number of gestational sacs into the poisson regression (PR) model. Factors were obtained from two study populations-cycles with double embryo transfer (DET) and cycles that transferred three embryos (TET). We sought to determine the factors that influenced the number of gestational sacs. These factors were entered into multivariable logistic regression (MLR) to identify risk factors for multiple pregnancies.

RESULTS

A total of 1000 patients referred to Royan Institute for ART during the study period. We included 606 eligible patients in this study. PR analysis demonstrated that the quality of transferred embryos and woman's age had a significant effect on the number of observed sacs in patients who underwent ICSI with DET. There was no significant predictive variable for multiple pregnancies according to MLR analysis. Our findings demonstrated that both regression models (PR and MLR) had the same outputs. A significant relation existed between age and fertilization rate with multiple pregnancies in patients who underwent ICSI with TET.

CONCLUSION

Single embryo transfer (SET) should be considered with the remaining embryos cryopreserved to prevent multiple pregnancies in women younger than 35 years of age who undergo ICSI cycles with high fertilization rates and good or excellent quality embryos. However, further prospective studies are necessary to evaluate whether SET in women with these risk factors can significantly decrease multiple pregnancies and improve cycle outcomes.

Impact of oocytes with CLCG on ICSI outcomes and their potential relation to pesticide exposure

BACKGROUND

Oocyte quality is a key limiting factor in female fertility which is primarily reflected in morphological features. Centrally located cytoplasm granulation (CLCG) is one type of cytoplasmic dimorphism exhibited by oocytes that could be linked to pesticide exposure with a significant risk of decreased ICSI outcomes.

METHODS

This retrospective study included 633 women who were part of an intracytoplasmic spermatozoa injection (ICSI) program between 2009 and 2011. The participants lived in the Picardy region of France and had been exposed to pesticides. The participants were divided in two groups based on prevalence of oocytes with CLCG (LCLCG [n = 83]: low prevalence of oocytes with CLCG under 25%. HCLCG [n = 68]: high prevalence of CLCG over 75%). The embryological and clinical outcomes were analysed for both groups and were calculated using the difference between the two values.

RESULTS

Results for couples with HCLCG compared to LCLCG showed a decrease in embryo cleavage, ongoing pregnancy, and live birth rates (82%, 14%, 13% vs 99%, 32%, 30%, respectively).The early miscarriage rate was increased (47% vs 11%), with an OR of 3.1 (95%CI [2.1-4.1]). Due to high pesticide exposure (over 3000 g/ha), there is a higher risk of a resulting disturbed oocyte cohort with a high prevalence of CLCG over 75%.

CONCLUSION

The high prevalence of oocytes with CLCG over 75% has a negative effect on embryos and the general ICSI clinical outcomes. Furthermore, a putative association between pesticide exposure and risk of CLCG was identified, justifying the need for further research and a potential need to find alternative assisted reproductive technologies for these couples.

TRIAL REGISTRATION

Tabacfertimasc. ID number: ID2011-A00634-37 ; registered 2011/2/8.

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.

Ultrastructural and cytogenetic analyses of mature human oocyte dysmorphisms with respect to clinical outcomes

PURPOSE

The study aimed to describe the ultrastructure of two human mature oocyte intracytoplasmic dysmorphisms, the bull-eye inclusion and the granular vacuole, with evaluation of clinical outcomes after intracytoplasmic sperm injection (ICSI) treatment.

METHODS

We retrospectively evaluated 4099 consecutive ICSI cycles during the period 2003-2013. Three groups were compared: controls, those with a bulls-eye inclusion, and those with granular vacuoles. Oocyte dysmorphisms were evaluated by transmission electron microscopy and in situ fluorescence hybridization (FISH). Detailed data on demographic and stimulation characteristics, as well as on embryological, clinical, and newborn outcomes, are fully presented.

RESULTS

The bull-eye inclusion is a prominent smooth round structure containing trapped vesicles, being surrounded by lipid droplets. The presence of this dysmorphism in the oocyte cohort had no clinical impact except when transferred embryos were exclusively derived from dysmorphism oocytes. The granular vacuole is delimited by a discontinuous double membrane and contains lipid droplets and vesicles. As FISH analysis revealed the presence of chromosomes, they probably represent pyknotic nuclei. The presence of this dysmorphism in the oocyte cohort had no clinical impact except when at least one transferred embryo was derived from dimorphic oocytes.

CONCLUSIONS

Poor clinical outcomes were observed with transfer of embryos derived from dysmorphism oocytes, although without causing gestation or newborn problems. The bull-eye inclusion and granular vacuoles may thus be new prognostic factors for clinical outcomes.