Tracking of oocyte dysmorphisms for ICSI patients may prove relevant to the outcome in subsequent patient cycles

A case report of a successful pregnancy after intracytoplasmic sperm injection when all oocytes contained abnormal inclusions in the perivitelline space

BACKGROUND

The relationship between oocyte morphology and developmental potential has been a hot research topic in assisted reproductive technology (ART). Whether inclusions in the perivitelline space (PVS) affect ART outcomes remains controversial.

CASE PRESENTATION

We present a case report of a 34-year-old G3P1A2 woman who sought ART treatment because of sequelae of pelvic disease. As her husband had severe oligospermia due to the stress on the day of oocyte retrieval, intracytoplasmic sperm injection (ICSI) was performed. After denudation, varying degrees of debris were found in the PVS, but all the oocytes were subjected to ICSI. Among the eleven retrieved oocytes, eight were fertilized. The morphology of the embryos was scored on Days 2 and 3. Five embryos were frozen on Day 3, and two best-quality embryos were subsequently transferred via frozen embryo transfer.

CONCLUSION

Severe debris in the PVS seems to affect embryo quality but not fertilization. Mild debris in the PVS may have little effect on the outcome of ART treatment. In our patient, after two embryos that were derived from oocytes with relatively few debris in the PVS were transferred, a successful live birth occurred.

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.

Mature oocyte dysmorphisms may be associated with progesterone levels, mitochondrial DNA content, and vitality in luteal granulosa cells

PURPOSE

To identify whether follicular environment parameters are associated with mature oocyte quality, embryological and clinical outcomes.

METHODS

This retrospective study examined 303 mature oocytes from 51 infertile women undergoing ICSI cycles between May 2018 and June 2021. Exclusion criteria consisted of advanced maternal age (> 36 years old), premature ovarian failure, obesity in women, or use of frozen gametes. Luteal granulosa cells (LGCs) were analyzed for mitochondrial DNA/genomic (g) DNA ratio and vitality. The relationships between hormone levels in the follicular fluid and oocyte features were assessed. Quantitative morphometric measurements of mature oocytes were assessed, and the association of LGC parameters and oocyte features on live birth rate after single embryo transfer was examined.

RESULTS

Results indicated an inverse correlation between the mtDNA/gDNA ratio of LGCs and the size of polar body I (PBI). A 4.0% decrease in PBI size was observed with each one-unit increase in the ratio (p = 0.04). Furthermore, a 1% increase in LGC vitality was linked to a 1.3% decrease in fragmented PBI (p = 0.03), and a 1 ng/mL increase in progesterone levels was associated with a 0.1% rise in oocytes with small inclusions (p = 0.015). Associations were drawn among LGC characteristics, perivitelline space (PVS) debris, cytoplasmic inclusions, PBI integrity, and progesterone levels. Certain dysmorphisms in mature oocytes were associated with embryo morphokinetics; however, live birth rates were not associated with follicular parameters and oocyte quality characteristics.

CONCLUSION

Follicular markers may be associated with mature oocyte quality features.

Does smooth endoplasmic reticulum aggregation in oocytes impact the chromosome aneuploidy of the subsequent embryos? A propensity score matching study

BACKGROUND

The appearance of smooth endoplasmic reticulum aggregation (SERa) is one of the most common dysmorphic phenotypes of oocytes, however, the impact of SERa occurrence on in vitro fertilization (IVF) outcomes is controversial. This study aimed to investigate the impact of SERa in oocytes on the aneuploidy of the subsequent embryos in IVF.

METHODS

In this retrospective cohort study, a total of 114 intracytoplasmic sperm injection (ICSI) cycles with the appearance of SERa undergoing preimplantation genetic testing for aneuploidy (PGT-A) were enrolled, and among them there were 323 SERa(+) oocytes and 1253 sibling unaffected oocytes. The 907 PGT-A cycles without SERa during the same period were enrolled as controls. A propensity score matching of 1:1 ratio between these two groups resulted in 113 matched cycles. The outcome parameters between the SERa(+) cycles/oocytes and the controls were compared. IVF laboratory outcomes, PGT-A outcomes, and clinical and neonatal outcomes were the main outcomes.

RESULTS

Increased abnormal fertilization rate and reduced blastocyst formation rate can be observed in both SERa(+) cycles and oocytes, some other parameters on developmental potential, such as available embryo rate at Day 3 and available blastocyst rate, were also impaired in the case of SERa occurrences. Among the 910 blastocysts for PGT-A, the percentage of euploid embryos was similar between the matched cohorts, while an unpredicted increase of the proportions of euploid in the SERa(+) oocytes, compared to the SERa(-) oocytes. Moreover, there was no significance in terms of clinical and neonatal outcomes, such as implantation rate, biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate, and live birth rate, regardless of the presence of SERa in cycles and oocytes.

CONCLUSIONS

The appearance of SERa within mature oocytes has no significant impact on the aneuploidy of subsequent blastocysts. It is recommended to utilize these oocytes, especially for those with few oocytes or advanced maternal age, which is likely to increase the cumulative pregnancy rate. This study may offer evidence to assist embryologists to make clinical decisions concerning SERa(+) oocytes more consciously and rationally.

Preimplantation genetic testing for aneuploidy in patients with low embryo numbers: benefit or harm?

PURPOSE

We sought to explore the utility of preimplantation genetic testing for aneuploidy (PGT-A) in a poor prognosis group of women with few embryos available for transfer.

METHODS

This was a retrospective matched cohort study examining records for first or second-cycle IVF patients with 1 to 3 blastocysts. The study group comprised 130 patients who underwent PGT-A on all embryos. The control group included 130 patients matched by age, BMI, and blastocyst number and quality who did not undergo PGT-A during the same time period.

RESULTS

The live birth rate (LBR) per embryo transfer (ET) were similar in the PGT-A and control groups, and the spontaneous abortion (SAB) rate was the same (23%). However, we found a significantly higher LBR per oocyte retrieval in the control group vs the PGT-A group (43% vs 20%, respectively) likely due to the many no-euploid cycles in the PGT-A group. In a subgroup analysis for age, the similar LBR per ET persisted in women < 38. However, in older women, there was a trend to a higher LBR per ET in the PGT-A group (43%) vs the control group (22%) but a higher LBR per oocyte retrieval in the control group (31%) vs the PGT-A group (13%).

CONCLUSIONS

Overall, we observed a significant increase in LBR per oocyte retrieval in women in the control group compared to women undergoing PGT-A, and no difference in SAB rate. Our data suggests that PGT-A has no benefit in a subpopulation of women with few embryos and may cause harm.

Different occurrence rates of centrally located cytoplasmic granulation in one cohort oocytes show distinctive embryo competence and clinical outcomes

Centrally located cytoplasmic granulation (central granulation) is a common cytoplasmic dysmorphism in human oocytes retrieved after controlled ovarian hyperstimulation (COH). In order to achieve a better understanding of its formation and effects on clinical outcomes, we retrospectively analyzed 422 ICSI treatment cycles. Three groups of patients were classified according to the ratio of central granulation occurrence in one egg cohort, as partial granulation, all granulation and control groups. The partial granulation group had a significantly lower BMI and higher AMH level compared to the control or all granulation groups. Consistent with these distinctive features in the partial granulation group, fertilization and blastocyst formation rates were reduced significantly in the partial granulation group but not in the all granulation group. Furthermore, the clinical outcomes in fresh embryo transfer cycles were dramatically reduced in the partial granulation group compared with the control group. However, in FET cycles, all three clinical outcomes were significantly reduced in the all granulation group but not in the partial granulation group. We propose that partial granulation may reflect a specific population of patients, and that the central granulation structure is sensitive to cryopreservation.

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.

Early and late paternal contribution to cell division of embryos in a time-lapse imaging incubation system

The objective of this study was to investigate the impact of male age, semen quality and days of ejaculatory abstinence on embryo morphokinetics. A total of 1,220 zygotes obtained from 139 couples in a private in vitro fertilisation centre were analysed. The timing of specific events from the point of insemination, such as timings to pronuclei appearance and fading, to two, three, four, five, six, seven and eight cells and to blastulation were recorded. Multivariate linear regression analysis was used to evaluate the influence of paternal factors on embryo morphokinetic events. Paternal age was positively correlated with delayed cell cleavage and blastulation, and negatively associated with implantation rate, and clinical pregnancy and live-birth chances. The ejaculatory abstinence was inversely correlated with the implantation rate. Inverse relationships were observed between semen parameters (sperm count, progressive sperm motility, total motile sperm count and morphology) and the timing of specific events during embryo development. Sperm morphology was also positively associated with implantation rate and pregnancy and live-birth chances. Increased paternal age and ejaculatory abstinence, and poor semen quality correlate with delayed cell cleavage and blastulation and negatively impact intracytoplasmic sperm injection 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.

Meta-analysis of the effects of smooth endoplasmic reticulum aggregation on birth outcome

BACKGROUND

Smooth endoplasmic reticulum aggregation (SERa, SER+) has been reported to increase the risk of birth malformations and other abnormal outcomes, miscarriage, and perinatal complications. Other studies, however, suggest that SER+ embryos may develop into healthy infants. One report indicates that 25% of in vitro fertilization (IVF) centers discard SER+ oocytes. Thus, we investigated the effect of SER+ on birth outcomes in IVF and intracytoplasmic sperm injection.

METHODS

We performed a literature search using PubMed, ScienceDirect, Cochrane, Embase, Ovid, and Scopus. We found a total of 1500 relevant studies between 1978 and 2020 and conducted a meta-analysis to study the effects of SER+ on live births, birth weight, and the number of metaphase II (MII) oocytes retrieved per cycle.

RESULTS

Eleven eligible studies were included. If the SER+ zygote was evaluated again at the embryo transfer (ET) stage, SER+ did not affect birth or infant body weight. Stimulated ovaries producing too many oocytes per cycle were positively correlated with SER+ (OR = 1.28, 95% CI = 0.41-2.15; p = 0.004). SER+ was positively correlated with oocyte maturation rate, and observed heterogeneity in a previous meta-analysis was likely due to maternal age. Our data also showed that SER+ cycles produced more oocytes but achieved the same number of births from ET.

CONCLUSIONS

The use of SER+ MII oocytes is rare, with the collection of many oocytes in 1 cycle potentially inducing SER+. SER+ may be more common than we originally thought, as some SER+ is found in all oocytes. Although SER+ positively affected oocyte maturation rate, it did not affect births. We hypothesized that this is because the best embryos are chosen at every step of the process, and the oocytes with the poorest characteristics are removed. We therefore suggest a standard method for measuring SER+. Although embryos produced from SER+ cycles can be used, they should only be transferred when no other suitable embryos are available over several cycles.

Visco- and poroelastic contributions of the zona pellucida to the mechanical response of oocytes

Probing mechanical properties of cells has been identified as a means to infer information on their current state, e.g. with respect to diseases or differentiation. Oocytes have gained particular interest, since mechanical parameters are considered potential indicators of the success of in vitro fertilisation procedures. Established tests provide the structural response of the oocyte resulting from the material properties of the cell's components and their disposition. Based on dedicated experiments and numerical simulations, we here provide novel insights on the origin of this response. In particular, polarised light microscopy is used to characterise the anisotropy of the zona pellucida, the outermost layer of the oocyte composed of glycoproteins. This information is combined with data on volumetric changes and the force measured in relaxation/cyclic, compression/indentation experiments to calibrate a multi-phasic hyper-viscoelastic model through inverse finite element analysis. These simulations capture the oocyte's overall force response, the distinct volume changes observed in the zona pellucida, and the structural alterations interpreted as a realignment of the glycoproteins with applied load. The analysis reveals the presence of two distinct timescales, roughly separated by three orders of magnitude, and associated with a rapid outflow of fluid across the external boundaries and a long-term, progressive relaxation of the glycoproteins, respectively. The new results allow breaking the overall response down into the contributions from fluid transport and the mechanical properties of the zona pellucida and ooplasm. In addition to the gain in fundamental knowledge, the outcome of this study may therefore serve an improved interpretation of the data obtained with current methods for mechanical oocyte characterisation.

Oocyte Degeneration After ICSI Is Not an Indicator of Live Birth in Young Women

INTRODUCTION

Intracytoplasmic sperm injection (ICSI) was introduced in 1990s as one of the most dramatic breakthroughs in assisted reproductive technology. Even with advances in ICSI technology, this mechanical micromanipulation carries a 5 to 19% risk of oocyte degeneration. Whether the presence of oocyte degeneration reflects the sibling oocyte quality and predicts the sibling embryo development potential and clinical pregnancy outcomes remains controversial. There is no study showing the competence of the sibling embryos from the prospective of cumulative live birth rate. Whether oocyte degeneration is associated with poor quality of the remainder of the cohort remains further to be elucidated.

METHOD

This retrospective observational study included a total of 488 OPU cycles underwent ICSI with fresh cleavage stage embryo transfer and successive frozen/thawed embryo transfer (FET) cycles from January 2018 to December 2019. All female patients were under the age of 35 years, and underwent ICSI with or without oocyte degeneration (OD). Cycles with at least one oocyte degenerated were defined as oocyte degeneration group (OD group), and cycles with no oocyte degenerated were defined as non-OD group. The OD group was further divided to three subgroups according to different oocyte degeneration rate (<10%, 10-20%, and >20%).

RESULTS

There were no significant differences with regards to implantation rate (38.5% vs 35.1%, P=0.302), clinical pregnancy rate (54.9% vs 50.3%, P=0.340), and LBR per OPU cycle (47.0% vs 42.9%, P=0.395) between OD and non-OD groups. Initial gonadotropin dosage, E₂ level on hCG day and the number of matured oocytes appeared to be independent risk factors for OD. The adjusted odds ratio of live birth rate per OPU cycle were similar in different oocyte degeneration rate subgroups. The ongoing pregnancy/LBR per transfer in FET cycles was not significantly different between OD group and non-OD groups (38.8% vs 43.9%, P=0.439). The cumulative LBR per OPU cycle was also comparable between OD and non-OD group (63.4% vs 64.8%, P=0.760).

CONCLUSION

The results provide cycle-based evidence that the presence of oocyte degeneration after ICSI is not an indicator for predicting the cumulative live birth rate per OPU cycle in young women.

Can Oocyte Diameter Predict Embryo Quality?

With the recent increased utilization of oocyte vitrification for the purpose of fertility preservation, information regarding the future fertility potential of the frozen oocytes is mandatory. Nowadays, there is a relative lack of data about prediction of assisted reproductive technique (ART) success relying on the retrieved oocytes. In the present study, we therefore aimed to investigate whether oocyte diameter might predict the quality of the developing embryo. A retrospective, single-center cohort study. Oocytes retrieved following controlled ovarian hyperstimulation cycles during 2016 and incubated in a time-lapse incubator system were analyzed. Oocytes were grouped by mean oocyte diameter (MOD) and incubated for 5 days before the final morphological evaluation done by an expert embryologist. A total of 471 cycles which yielded 3355 metaphase II oocytes were included in the analysis. Embryos developed from oocytes with MOD close to the average (Average 1SD < MOD < Average + 1SD) had increased good-quality blastulation rates compared with embryos that developed from very small or very large oocytes. Oocytes with MOD between 105.96 and 118.69 μm have better probability of becoming top-quality D5 blastocysts (17.1-17.4% grade 1 embryos). There is a correlation between oocyte's MOD and the embryo quality at day 5. The oocytes with near average MOD have a better chance to develop to a good-quality embryo. Therefore, the study suggests that MOD might serve as a predictor for embryo grading at day 5.

Effect of GnRH analogues for pituitary suppression on oocyte morphology in repeated ovarian stimulation cycles

OBJECTIVE

To compare the effect of pituitary suppression regimens on oocyte morphology in consecutive ICSI cycles of the same patients.

METHODS

Data was obtained from 200 matched consecutive intracytoplasmic sperm injection (ICSI) cycles performed in 100 couples undergoing the first cycle with the GnRH agonist and the following cycle with the GnRH antagonist regimen, from January 2010 to August 2016, in a private university-affiliated IVF centre. The effects of the pituitary suppression type on oocyte morphology were assessed by multivariate General Linear Models.

RESULTS

Mean interval between cycles was 185.32±192.85 days. Maternal age, body mass index, and total FSH dose administered were similar in both patients' cycles. Antagonist cycles presented lower incidence of dark cytoplasm (0.69±3.28% vs. 4.40±17.70%, p=0.047), Smooth endoplasmic reticulum (SER cluster (4.37±11.62% vs. 7.36±17.17%, p=0.046), and ZP defects (6.05±14.76% vs. 11.84±25.13%, p=0.049). Similar numbers of follicles retrieved oocytes, and mature oocytes were observed between the GnRH groups, as well as the fertilisation rate, number of obtained embryos, high-quality embryo rates, and the clinical outcomes.

CONCLUSION

GnRH antagonist's inhibitory effect on the ovaries in consecutive ICSI cycles results in improved oocyte maturity and morphology, despite similar laboratory and clinical outcomes, compared to the GnRH agonist treatment.

Mitochondrial dynamics and interorganellar communication in the development and dysmorphism of mammalian oocytes

Mitochondria play many critical roles in cells, not only by supplying energy, but also by supplying metabolites, buffering Ca2+ levels and regulating apoptosis. During oocyte maturation and subsequent embryo development, mitochondria change their morphology by membrane fusion and fission, and coordinately undergo multiple cellular events with the endoplasmic reticulum (ER) closely apposed. Mitochondrial fusion and fission, known as mitochondrial dynamics, are regulated by family members of dynamin GTPases. Oocytes in animal models with these regulators artificially altered exhibit morphological abnormalities in nearby mitochondria and at the ER interface that are reminiscent of major cytoplasmic dysmorphisms in human assisted reproductive technology, in which a portion of mature oocytes retrieved from patients contain cytoplasmic dysmorphisms associated with mitochondria and ER abnormal morphologies. Understanding organelle morpho-homeostasis in oocytes obtained from animal models will contribute to the development of novel methods for determining oocyte health and for how to deal with dysmorphic oocytes.

Presence of aggregates of smooth endoplasmic reticulum in MII oocytes affects oocyte competence: molecular-based evidence

STUDY QUESTION

Does the presence of aggregates of smooth endoplasmic reticulum (SERa) impact the transcriptome of human metaphase II (MII) oocytes?.

SUMMARY ANSWER

The presence of SERa alters the molecular status of human metaphase II oocytes.

WHAT IS KNOWN ALREADY

Oocytes presenting SERa are considered dysmorphic. Oocytes with SERa (SERa+) have been associated with reduced embryological outcome and increased risk of congenital anomalies, although some authors have reported that SERa+ oocytes can lead to healthy newborns. The question of whether or not SERa+ oocytes should be discarded is still open for debate, and no experimental information about the effect of the presence of SERa on the oocyte molecular status is available.

STUDY DESIGN, SIZE, DURATION

This study included 28 women, aged <38 years, without any ovarian pathology, and undergoing IVF treatment. Supernumerary MII oocytes with no sign of morphological alterations as well as SERa+ oocytes were donated after written informed consent. A total of 31 oocytes without SERa (SERa-) and 24 SERa+ oocytes were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Pools of 8-10 oocytes for both group were prepared. Total RNA was extracted from each pool, amplified, labeled and hybridized on oligonucleotide microarrays. Analyses were performed by R software using the limma package.

MAIN RESULTS AND THE ROLE OF CHANCE

The expression profiles of SERa+ oocytes significantly differed from those of SERa- oocytes in 488 probe sets corresponding to 102 down-regulated and 283 up-regulated unique transcripts. Gene Ontology analysis by DAVID bioinformatics disclosed that genes involved in three main biological processes were significantly down-regulated in SERa+ oocytes respective to SERa- oocytes: (i) cell and mitotic/meiotic nuclear division, spindle assembly, chromosome partition and G2/M transition of mitotic cell cycle; (ii) organization of cytoskeleton and microtubules; and (iii) mitochondrial structure and activity. Among the transcripts up-regulated in SERa+ oocytes, the most significantly (P = 0.002) enriched GO term was 'GoLoco motif', including the RAP1GAP, GPSM3 and GPSM1 genes.

LARGE SCALE DATA

Raw microarray data are accessible through GEO Series accession number GSE106222 (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE106222).

LIMITATIONS, REASONS FOR CAUTION

Data validation in a larger cohort of samples would be beneficial, although we applied stringent criteria for gene selection (fold-change >3 or <1/3 and FDR < 0.1). Surveys on clinical outcomes, malformation rates and follow-up of babies born after transfer of embryos from SERa+ oocytes are necessary.

WIDER IMPLICATIONS OF THE FINDINGS

We provide information on the molecular status of SERa+ oocytes, highlighting possible associations between presence of SERa, altered oocyte physiology and reduced developmental competence. Our study may offer further information that can assist embryologists to make decisions on whether, and with what possible implications, SERa+ oocytes should be used. We believe that the presence of SERa should be still a 'red flag' in IVF practices and that the decision to inseminate SERa+ oocytes should be discussed on a case-by-case basis.

STUDY FUNDING/COMPETING INTEREST(s)

This study was partially supported by Ferring Pharmaceuticals. The authors have no conflicts of interest to declare.

Separating the contributions of zona pellucida and cytoplasm in the viscoelastic response of human oocytes

The successful characterization of the mechanical properties of human oocytes and young embryos is of crucial relevance to reduce the risk of pregnancy arrest in in-vitro fertilization processes. Unfortunately, current study has been hindered by the lack of accuracy in describing the mechanical contributions of each structure (zona pellucida, cytoplasm) due to its high heterogeneity. In this work, we present a novel approach to model the oocyte response taking into account the effect of both zona and cytoplasm, as well as different loading conditions. The model is then applied to develop an experimental protocol capable of accurately separating the viscoelastic contribution of zona and cytoplasm by simply varying the loading condition. This new protocol has the potential to open the door to improving our understanding the mechanical properties of oocytes at different stages, and provide a quantitative predictive ability to the evaluation of oocyte quality. STATEMENT OF SIGNIFICANCE: Assisted reproductive technologies, such as in vitro fertilization, often rely on identifying high quality oocytes or female egg cells. The viscoelastic properties of these cells, such as stiffness and stress relaxation time, have been identified as potential objective indicators of cell quality. However, their characterization has proven difficult due to the structural heterogeneity of the cell and inconsistent loading conditions. This paper presents a new model that, although simple, addresses the above difficulties to provide accurate estimations of the cell's mechanical properties. Learning from this model, we then propose a novel non-invasive testing protocol to allow oocyte characterization with increased accuracy. We believe this effort would improve consistency in measurements and enhance our knowledge on the mechanics of oocytes.

Dysmorphic patterns are associated with cytoskeletal alterations in human oocytes

Study question

Are specific morphological anomalies in human mature oocytes, as revealed by transmitted light microscopy, associated with intrinsic damage to the meiotic spindle and actin cytoskeleton?

Summary answer

Aggregates of smooth endoplasmic reticulum (SER) and domains of centrally localized granular cytoplasm (GC) reflect intrinsic damage to the oocyte cytoskeleton, namely alterations in spindle size, chromosome misalignment and cortical actin disorganization.

What is known already

In preparation for ICSI, oocytes are often selected for use in treatment by morphological criteria, but the rationale and implications of this practice are controversial. Very little information is available on the relationship between oocyte morphology and intrinsic cellular characteristics, such as the actin cytoskeleton, meiotic spindle and chromosome alignment.

Study design, size, duration

A total of 170 metaphase II (MII) oocytes were donated by consenting IVF patients and analysed; 62 were classified as morphologically normal (control), 54 had SER clusters and 54 had centrally localized GC.

Participants/materials, setting, methods

Supernumerary oocytes were fixed within 3 h from recovery and stained for tubulin, chromatin and actin. Spindles were analysed for 1D and 2D characteristics by high-performance confocal microscopy. Chromosomes were classified as scattered or aligned and the conformation and intensity of cortical actin was evaluated.

Main results and the role of chance

In comparison with control oocytes, both SER and GC oocytes showed greater spindle length (P = 0.033 and 0.003, respectively) and GC oocytes also showed greater spindle width (P= 0.049) and area (P= 0.036). Control and SER oocytes had statistically comparable rates of chromosome displacement from the metaphase plate, unlike GC oocytes where chromosome displacement occurred at higher rate (P = 0.013). In situations where a complete Z-stack was reconstructed from a polar angle, chromosome disposition was classified as being normal when two sets of concentric arrays were visible. Based on these parameters, the proportions of oocytes with normal chromosomal arrangement or partial/total disarrangement was not statistically different between control and SER oocytes. Conversely, in GC oocytes, chromosome disarrangement was higher (P = 0.002). All control oocytes displayed a continuous meshwork of suboolemmal actin, which appeared as an uninterrupted ring in thin optical sections. In contrast, in SER and  GC groups, integrity of suboolemmal actin was observed in only 66.7 and 42.9% of oocytes, respectively (P = 0.0001).

Large scale data

N/A.

Limitations reason for caution

Only two of several known oocyte dysmorphisms were investigated, while oocyte quality was assessed only by cytoskeletal criteria.

Wider implications of the findings

This study represents a significant step toward a more objective assessment of oocyte morphology, offering information that can assist embryologists to make a more aware and rationally founded decision on whether, and with what possible implications, oocytes with certain dysmorphic characters should be used for treatment or discarded. More generally, it also demonstrates that morphometric parameters of the cytoskeleton and chromosome organization can be used as biomarkers of oocyte quality.

Study funding and competing interest(s)

This study was funded by Biogenesi Reproductive Medicine Centre (Monza, Italy). All authors declare no conflict of interests.

Does oval oocyte have an impact on embryo development in in vitro fertilization?

OBJECTIVE

To compare the outcomes of embryo development between oval-shaped oocyte as an abnormal morphology oocyte and a normal morphology oocyte in In Vitro Fertilization (IVF).

METHODS

This study was a comparative analytical study with retrospective approach which lasted from September 2014 until November 2015. For this study, we used secondary data (medical records) from 24 patients submitted to IVF at the Halim Fertility Center. The oocyte morphology was divided into two groups: normal-shaped oocyte and oval-shaped oocyte.

RESULTS

Our study included 120 oocytes with 60 oval-shaped oocytes and 60 normal oocytes. We found fertilization rates of 68.3% in the normal oocyte group and 61.7% in the oval-shaped oocyte group; and there was no significant difference between the normal oocyte group and the oval-shaped oocyte group (p > 0.05). In the normal oocyte group, 65% had reached day 3 embryos, and in the oval-shaped oocyte group it was 50%, with no significant difference between the groups (p > 0.05). We also found 46.7% transferrable embryos in the oval oocytes group compared to 63.3% in the normal oocytes group, with no significant difference between the groups (p > 0.05).

CONCLUSION

There was no significant difference in fertilization rates and embryo quality between normal morphology oocytes and oval-shaped oocytes.

Oocytes with smooth endoplasmic reticulum clusters originate blastocysts with impaired implantation potential

OBJECTIVE

To study whether embryos derived from oocytes presenting a smooth endoplasmic reticulum cluster (SERC) are less likely to develop into blastocysts and implant.

DESIGN

Transversal study.

SETTING

Private university-affiliated in vitro fertilization (IVF) center.

PATIENT(S)

Total of 7,609 oocytes obtained from 743 intracytoplasmic sperm injection (ICSI) cycles.

INTERVENTION(S)

Oocytes split between the SERC-positive cycles (with at least one SERC-positive oocyte) and the SERC-negative cycles (only oocytes free of SERC).

MAIN OUTCOME MEASURE(S)

Embryo implantation.

RESULT(S)

A statistically significantly higher mean number of follicles (24.0 ± 10.5 vs. 19.6 ± 10.5), retrieved oocytes (17.8 ± 8.3 vs. 14.3 ± 8.0), and mature oocytes (13.5 ± 6.2 vs. 10.6 ± 5.9) were observed in the SERC-positive cycles as compared with SERC-negative cycles. The implantation rate was statistically significantly lower in SERC-positive cycles as compared with SERC-negative cycles (14.8% vs. 25.6%; odds ratio 0.61; 95% confidence interval, 0.44-0.86). When only cycles with in which none (0) or all the blastocysts transferred had implanted (100%) were analyzed, the mean implantation rate per transferred blastocyst in the SERC-negative group was 20.5%; no blastocysts derived from SERC-positive oocytes implanted.

CONCLUSION(S)

The occurrence of SERC impairs embryo implantation. Careful oocyte observation that takes into account the presence of SERC should be part of embryo selection strategy before transfer.

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

AIM

The aim of this study was to identify the influence of oocyte dysmorphisms on clinical outcomes after intracytoplasmic sperm injection cycle in normal responders.

MATERIAL AND METHODS

In the prospective study, morphology of 1999 metaphase II oocytes retrieved from 316 intracytoplasmic sperm injection cycles was evaluated from March 2011 to March 2013 at Royan Institute. Controlled ovarian stimulation was performed by long standard agonist protocol. Oocyte morphology was assessed before sperm injection by one embryologist. The associations between fertilization rate, embryo quality and the independent variables were analyzed using odds ratio (OR) calculated with unconditional logistic regression test.

RESULTS

From all retrieved oocytes, 1543 (77.1%) showed at least one morphologic aberration. Presence of cytoplasmic vacuoles and high cytoplasmic viscosity were associated with a significant decrease in the fertilization rate (OR: 0.5; P = 0.004 and OR: 0.6; P = 0.03, respectively). The results showed that oocyte morphology did not affect embryo quality. The number of gonadotrophin injections used showed a direct relation with presence of large perivitelline space. No significant difference was observed among four groups (women with total normal morphologic oocytes [group 1], women with total extracytoplasmic dysmorphic oocytes [group 2], women with total cytoplasmic dysmorphic oocytes [group 3] and women with total oocytes containing multiple dysmorphic features [group 4]) in terms of implantation and clinical pregnancy rates.

CONCLUSIONS

Metaphase II oocyte morphology had minor impacts on fertilization rate, pronuclear morphology and embryo quality in women with normal ovarian response.

Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study

PURPOSE

The presence of Smooth Endoplasmic Reticulum aggregates (SERa) has been reported to be associated with adverse outcomes. An Alpha-ESHRE Consensus was published in 2011, strongly recommending to not inseminating affected oocytes. On the other hand, healthy babies have been born from oocytes presenting this dysmorphism. We surveyed several European IVF centres, to assess their attitudes concerning affected oocytes.

METHODS

This survey is based on a computer format and includes questions regarding the fate of affected oocytes.

RESULTS

About 14 % of centres who answered our survey discard SERa+ oocytes. 43 % of centres that do not discard the oocytes, register and follow up neonatal data. About a quarter of centres inform their patients about this dysmorphism. Half of them require an informed consent prior to transferring affected embryos. Twenty-one centres reported having SERa+ births, with one reporting a malformation. 48 % of centres declared having been influenced by the Alpha-ESHRE Consensus, in their management policy of SERa+ oocytes.

CONCLUSIONS

Few centres scrupulously respect the recommendations of the Alpha-ESHRE Consensus and discard affected oocytes. Since it is essential to determine if there truly is an impact of this dysmorphism and whether the guidelines are still valid, transfer of affected embryos should only be done when accompanied with data recording and monitoring of all foetal malformations from IVF. Clarifying the situation will allow IVF centres to correctly inform patients about the risk of birth malformations as well as whether a decreased chance of pregnancy exists.

Total fertilization failure: is it the end of the story?

PURPOSE

To study parameters that could predict in-vitro fertilization (IVF) success in patients who experienced total fertilization failure (TFF) with intracytoplasmic sperm injection (ICSI) in their previous cycles.

METHODS

Cycle characteristics of patients with TFF (Group I, n = 136 cycles), cycles resulting in embryo transfer (ET) following TFF (Group II, n = 36 cycles) and recurrent TFF (Group III, n = 25 cycles) and were studied retrospectively. Demographic features, cycle characteristics of three groups were compared.

RESULTS

Follicle count measuring 15-17 mm was significantly higher in group II when compared to group I (p = 0.02). Total number of retrieved oocytes and mature oocytes were significantly higher in group II when compared to groups I and III (p = 0.001). Estradiol level at oocyte pick up (OPU) day was significantly higher in group II when compared to group I (p = 0.02). When the characteristics of ET cycles and preceding TFF cycles of the same patient were compared, total number of retrieved oocytes (5.11 ± 0.72 (95% CI 3.69-6.52) vs. 11.44 ± 1.60 (95% CI 5.29-17.59)) and mature oocytes (3.26 ± 3.66 (95% CI 2.04-4.47) vs. 6.92 ± 5.61 (95% CI 5.09-8.75)) were found to be significantly lower in TFF cycles (p = 0.001). Five biochemical and 5 clinical pregnancies occurred while only 2 healthy babies were born, corresponding to a live birth rate 5.5%.

CONCLUSIONS

Increasing the number of retrieved and mature oocytes may increase the success of fertilization in patients with a history of previous failed fertilization. However, live birth rate is still low in embryo transfer cycles.

Pregnancy with oocytes characterized by narrow perivitelline space and heterogeneous zona pellucida: is intracytoplasmic sperm injection necessary?

PURPOSE

This retrospective study analyzed fertilization protocols and pregnancy outcomes for oocytes with with narrow perivitelline space and heterogeneous zona pellucid (NPVS/HZP).

METHODS

In 63 in-vitro fertilization cycles filled with NPVS/HZP oocytes (abnormal oocytes group) and 521 cycles with normal oocytes (normal oocytes group), major clinical and laboratory parameters were recorded and compared in different fertilization cycles (conventional IVF cycles, rescue ICSI cycles, and traditional ICSI cycles).

RESULTS

NPVS/HZP oocytes meant lower MIIoocytes rates in both IVF and ICSI cycles compared with normal oocytes (p < 0.05). The 2PN rates for abnormal oocytes were significantly lower than those for normal oocytes in both conventional IVF cycles (58.8% VS 71.3%, P < 0.05) and rescue ICSI cycles (58.0% VS 78.0%, P = 0.0000). The high-quality embryo rates in normal oocytes groups were significantly higher than those in abnormal oocytes groups in different fertilization cycles (52.2% VS 35.0%, P < 0.01; 42.9% VS 23.9%, P < 0.001; 50.6% VS 31.0%, P = 0.0000, respectively). No clinical pregnancy was obtained from abnormal oocytes in 11 conventional IVF cycles. The clinical pregnancy rates in rescue ICSI and traditional ICSI cycles were comparatively lower in abnormal oocytes groups, but there was no significant difference as compared with normal oocytes groups (35.0% VS 48.1% and 26.7% VS 50.7%, P > 0.05, respectively).

CONCLUSIONS

Retrieval of oocytes characterized by NPVS/PZP from cycle to cycle was one of the reasons for obscure infertility. ICSI may be the right way to avoid fertilization failure and get pregnancy in women with NPVS/HZP oocytes.

Health outcomes of children born after IVF/ICSI: a review of current expert opinion and literature

The Sixth Evian Annual Reproduction (EVAR) Workshop Group Meeting was held to evaluate the impact of IVF/intracytoplasmic sperm injection on the health of assisted-conception children. Epidemiologists, reproductive endocrinologists, embryologists and geneticists presented data from published literature and ongoing research on the incidence of genetic and epigenetic abnormalities and congenital malformations in assisted-conception versus naturally conceived children to reach a consensus on the reasons for potential differences in outcomes between these two groups. IVF-conceived children have lower birthweights and higher peripheral fat, blood pressure and fasting glucose concentrations than controls. Growth, development and cognitive function in assisted-conception children are similar to controls. The absolute risk of imprinting disorders after assisted reproduction is less than 1%. A direct link between assisted reproduction and health-related outcomes in assisted-conception children could not be established. Women undergoing assisted reproduction are often older, increasing the chances of obtaining abnormal gametes that may cause deviations in outcomes between assisted-conception and naturally conceived children. However, after taking into account these factors, it is not clear to what extent poorer outcomes are due to the assisted reproduction procedures themselves. Large-scale, multicentre, prospective epidemiological studies are needed to investigate this further and to confirm long-term health consequences in assisted-conception children. Assisted reproduction treatment is a general term used to describe methods of achieving pregnancy by artificial means and includes IVF and sperm implantation. The effect of assisted reproduction treatment on the health of children born using these artificial methods is not fully understood. In April 2011, fertility research experts met to give presentations based on research in this area and to look carefully at the evidence for the effects of assisted reproduction treatment on children's health. The purpose of this review was to reach an agreement on whether there are differences in the health of assisted-conception children with naturally conceived children. The researchers discovered no increased risk in birth defects in assisted-conception children compared with naturally conceived children. They found that IVF-conceived children have lower birth weights and higher fat under the skin, higher blood pressure and higher fasting glucose concentrations than naturally conceived children; however, growth, development and cognitive function are similar between groups. A very low risk of disorders of genetic control was observed in assisted-conception children. Overall, there did not appear to be a direct link between assisted reproduction treatment and children's health. The researchers concluded that the cause of some differences in the health of children conceived using assisted reproduction treatment may be due to the age of the woman receiving treatment. Large-scale, research studies are needed to study the long-term health of children conceived using assisted reproduction treatment.

Embryological, clinical and ultrastructural study of human oocytes presenting indented zona pellucida

Human oocyte dysmorphisms attain a large proportion of retrieved oocytes from assisted reproductive technology (ART) treatment cycles. Extracytoplasmic defects involve abnormal morphology of the zona pellucida (ZP), perivitelline space and first polar body. The aim of the present study was to describe a novel dysmorphism affecting the ZP, indented ZP. We also evaluated the clinical, embryological and ultrastructural features of these cases. We evaluated all ART treatment cycles during 7 consecutive years and found 13 treatment cycles (six patients) with all oocytes presenting an indented ZP. In addition, these oocytes presented total or partial absence of the perivitelline space, absence of resistance to ZP and oolemma penetration during microinjection, and low ooplasm viscosity during aspiration. This novel described dysmorphism was recurrent and attained all oocytes in three cases that had more than one treatment cycle. When compared with controls, data showed significant low oocyte maturity (42% versus 81.6%) and high cycle cancellation (30.8% versus 8.5%) rates, normal degeneration (3.4% versus 6.3%) and fertilization rates (69% versus 69.5%), and low pregnancy (15.4% versus 33.3%) and live-birth delivery (7.7% versus 27.7%) rates per cycle. Ultrastructure analysis revealed a zona pellucida structure with large empty electrolucent regions, an outer ZP layer with an indented surface with protuberances and a thick inner ZP that obliterated the perivitelline space. There was evidence of exocytosis of ZP material by the oocyte. In conclusion, oocytes with this novel described dysmorphism (indented ZP) are associated with low maturity, pregnancy and live-birth delivery rates.

Importance of cytoplasmic granularity of human oocytes in in vitro fertilization treatments

The aim of this study was to examine the effect of different stimulation protocols on oocyte granularity and to determine the influence of cytoplasmic granularity on further embryo development. A total of 2448 oocytes from 393 intracytoplasmic sperm injection (ICSI) cycles were analysed retrospectively. Oocytes were classified into 5 groups according to cytoplasmic granularity. (A) no granule or 1-2 small (<5 μm) granules; (B) more than 3 small granules; (C) large granules (>5 μm); (D) refractile body; (E) dense centrally located granular area. Correlation between characteristics of hormonal stimulation, oocyte granularity and embryo development was analysed. The occurrence of cytoplasmic granularity was influenced by the patient's age and characteristics of stimulation. The type of granulation had no effect on fertilization rate and zygote morphology. However, some type of granulation resulted in a lower cleavage rate and more fragmented embryos. Our results provided additional information on how hormonal stimulation affects oocyte quality. While cytoplasmic granularity seems not to have an effect on fertilization and embryo development, the presence of refractile body in the oocyte is associated with reduced cleavage rates and impaired embryo development.

GnRH agonist versus GnRH antagonist in assisted reproduction cycles: oocyte morphology

BACKGROUND

The selection of developmentally competent human gametes may increase the efficiency of assisted reproduction. Spermatozoa and oocytes are usually assessed according to morphological criteria. Oocyte morphology can be affected by the age, genetic characteristics, and factors related to controlled ovarian stimulation. However, there is a lack of evidence in the literature concerning the effect of gonadotropin-releasing hormone (GnRH) analogues, either agonists or antagonists, on oocyte morphology. The aim of this randomized study was to investigate whether the prevalence of oocyte dysmorphism is influenced by the type of pituitary suppression used in ovarian stimulation.

METHODS

A total of 64 patients in the first intracytoplasmic sperm injection (ICSI) cycle were prospectively randomized to receive treatment with either a GnRH agonist with a long-term protocol (n: 32) or a GnRH antagonist with a multi-dose protocol (n: 32). Before being subjected to ICSI, the oocytes at metaphase II from both groups were morphologically analyzed under an inverted light microscope at 400x magnification. The oocytes were classified as follows: normal or with cytoplasmic dysmorphism, extracytoplasmic dysmorphism, or both. The number of dysmorphic oocytes per total number of oocytes was analyzed.

RESULTS

Out of a total of 681 oocytes, 189 (27.8%) were morphologically normal, 220 (32.3%) showed cytoplasmic dysmorphism, 124 (18.2%) showed extracytoplasmic alterations, and 148 (21.7%) exhibited both types of dysmorphism. No significant difference in oocyte dysmorphism was observed between the agonist- and antagonist-treated groups (P>0.05). Analysis for each dysmorphism revealed that the most common conditions were alterations in polar body shape (31.3%) and the presence of diffuse cytoplasmic granulations (22.8%), refractile bodies (18.5%) and central cytoplasmic granulations (13.6%). There was no significant difference among individual oocyte dysmorphisms in the agonist- and antagonist-treated groups (P>0.05).

CONCLUSIONS

Our randomized data indicate that in terms of the quality of oocyte morphology, there is no difference between the antagonist multi-dose protocol and the long-term agonist protocol. If a GnRH analogue used for pituitary suppression in IVF cycles influences the prevalence of oocyte dysmorphisms, there does not appear to be a difference between the use of an agonist as opposed to an antagonist.

Relationship between oocyte abnormal morphology and intracytoplasmic sperm injection outcomes: a meta-analysis

The aim of this study was to perform a meta-analysis of the potential effects of oocyte morphological abnormalities on ICSI outcomes. Relevant original papers reporting on the relation between oocyte morphology and ICSI outcomes were identified by searching MEDLINE, EMBASE and the Cochrane Library. The main outcome measures were fertilisation rate and embryo quality. A meta-analysis was performed and Mantel-Haenszel pooled odd ratios (ORs) with 95% confidence intervals (CIs) were calculated to express the relation between the oocyte morphology and the ICSI outcomes. A total of 14 studies reporting 3688 ICSI cycles were included. Our meta-analysis demonstrates that the probability of an oocyte becoming fertilised is significantly reduced by the presence of large IPB (OR: 0.29, CI: 0.09-0.90), large PVS (OR: 0.86, CI: 0.74-0.99), refractile bodies (OR: 0.66, CI: 0.51-0.84) or vacuoles (OR: 0.59, CI: 0.42-0.83). No other investigated morphological abnormalities demonstrated significant relationships with ICSI outcomes. Our data demonstrate that the presence of large IPB, large PVS, refractile bodies or vacuoles is associated with decreased oocyte fertilisation. Our findings might be of importance for selecting embryos for replacement because the effects of oocyte abnormalities on implantation and pregnancy rates remain unclear.

Mitochondrial function in the human oocyte and embryo and their role in developmental competence

The role of mitochondria as a nexus of developmental regulation in mammalian oogenesis and early embryogenesis is emerging from basic research in model species and from clinical studies in infertility treatments that require in vitro fertilization and embryo culture. Here, mitochondrial bioenergetic activities and roles in calcium homeostasis, regulation of cytoplasmic redox state, and signal transduction are discussed with respect to outcome in general, and as possible etiologies of chromosomal defects, maturation and fertilization failure in human oocytes, and as causative factors in early human embryo demise. At present, the ability of mitochondria to balance ATP supply and demand is considered the most critical factor with respect to fertilization competence for the oocyte and developmental competence for the embryo. mtDNA copy number, the timing of mtDNA replication during oocyte maturation, and the numerical size of the mitochondrial complement in the oocyte are evaluated with respect to their relative contribution to the establishment of developmental competence. Rather than net cytoplasmic bioenergetic capacity, the notion of functional compartmentalization of mitochondria is presented as a means by which ATP may be differentially supplied and localized within the cytoplasm by virtue of stage-specific changes in mitochondrial density and potential (ΔΨm). Abnormal patterns of calcium release and sequestration detected at fertilization in the human appear to have coincident effects on levels of mitochondrial ATP generation. These aberrations are not uncommon in oocytes obtained after ovarian hyperstimulation for in vitro fertilization. The possibility that defects in mitochondrial calcium regulation or bioenergetic homeostasis could have negative downstream development consequences, including imprinting disorders, is discussed in the context of signaling pathways and cytoplasmic redox state.

Relationship between first polar body morphology before intracytoplasmic sperm injection and fertilization rate, cleavage rate, and embryo quality

OBJECTIVES

To evaluate the influence of the morphology of the first polar body (PB) on intracytoplasmic sperm injection (ICSI) outcomes.

METHODS

The morphology of the first PB was assessed in 3177 metaphase II oocytes and classified as: intact and normal size, fragmented, or enlarged size. The rates of fertilization, cleavage, and embryo quality were evaluated on day 2.

RESULTS

The rates of fertilization, cleavage, and formation of good quality embryos resulting from the insemination of oocytes with an enlarged first PB (20.7%, 18.7%, and 5.0%, respectively) were significantly lower than those for oocytes with an intact first PB of normal size (70.8%, 62.5%, and 19%, respectively) or a fragmented first PB (69.7%, 60.5%, and 17.1%, respectively). Rates did not differ significantly between oocytes with an intact first PB of normal size and oocytes with a fragmented first PB (P>0.05).

CONCLUSIONS

The presence of an enlarged PB is related to poorer rates of fertilization, cleavage, and top quality embryos. However, identification of first PB fragmentation does not seem to interfere with ICSI outcomes.

Morphological selection of gametes

Methods of selecting gametes before the intracytoplasmic sperm injection (ICSI) technique are of paramount importance, especially where for religious, ethical or legal reasons the production of supernumerary embryos has to be avoided. In these circumstances, in fact, the research has to be focused on the identification of early markers of embryo quality at the oocyte and sperm stage before fertilisation. Oocyte quality can be influenced by several factors such as controlled ovarian hyperstimulation protocols, pharmaceutical preparations and perifollicular vascularisation. Several intracytoplasmic and extracytoplasmic abnormalities have been described, but whether these abnormalities might be predictive of oocyte competence is controversial and the selection methods proposed are still poorly effective. Recently, we have observed that oocyte morphological abnormalities might be indicators of oocyte competence. An abnormal first polar body (but not fragmented), a large perivitelline space, increased cytoplasmic granularity, and the presence of a centrally located granular area seem to have a negative effect on the oocyte potential to fertilise, cleave, and/or develop into a viable embryo. Sperm morphology can be more accurately observed at high magnification using an inverted microscope equipped with Normarski optics (1000x magnification under mineral oil) and a digital system in order to reach a final magnification of approximately 6300x. Single sperm nuclear abnormalities based on strict selection criteria seems to have a clear negative association with ICSI outcome. The possibility of observing the spermatozoa in real time at higher magnification might also be a good opportunity to study the relationship between particular sperm defects and ICSI outcome. In addition to morphology, it has been suggested that spermatozoa selection might be performed on the basis of its biochemical ability to bind to solid hyaluronic acid. However, it must be underlined that prospective randomised studies are necessary to confirm the preliminary results regarding the efficacy of the described criteria proposed, to morphologically select gametes prior to in vitro insemination.

Severe cytoplasmic abnormalities of the oocyte decrease cryosurvival and subsequent embryonic development of cryopreserved embryos

BACKGROUND

Abnormalities of oocyte morphology affect embryo quality and viability. Whether morphological abnormalities of the oocyte influence cryosurvival and further development of derived embryos is not known. The aim of this study was to compare cryosurvival and progression to the blastocyst stage of frozen-thawed embryos derived from normal and abnormal oocytes.

METHODS

A total of 5292 Grade 1 and 2 embryos from 964 women were frozen, thawed and subsequently cultured up to the blastocyst stage. The study was performed on excess embryos from patients who did not opt for cryopreservation. Cryosurvival, progression to the blastocyst stage and hatching were correlated with morphological characteristics of the oocytes that embryos were derived from.

RESULTS

Presence of a cytoplasmic abnormality of the oocyte significantly decreased cryosurvival. This detrimental effect was more pronounced in embryos derived from oocytes with vacuolar cytoplasm or with central granulation. Furthermore, these embryos did not have the potential to develop into good quality blastocysts or reach the hatching stage. On the other hand, presence of a single extracytoplasmic abnormality of the oocyte did not affect cryosurvival and the potential to develop into good quality blastocysts. Grade 2 embryos derived from oocytes with irregular shape or a large perivitelline space had decreased cryosurvival. However when these embryos survived cryopreservation, their potential to develop good quality blastocysts or to reach hatching stage was unaffected.

CONCLUSIONS

Embryos derived from oocytes with vacuolar cytoplasm or central granulation do not seem to bear the potential to develop good quality blastocysts or to reach hatching stage after cryopreservation. The presence of extracytoplasmic abnormalities alone does not affect blastocyst development despite decreasing cryosurvival.

Significance of metaphase II human oocyte morphology on ICSI outcome

OBJECTIVE

To evaluate the influence of specific oocyte morphologic features (morphotypes) on intracytoplasmic sperm injection (ICSI) outcome. The identification of oocyte quality markers is particularly important when a low number of oocytes can be used for IVF.

DESIGN

Retrospective analysis.

SETTING

Medical center.

PATIENT(S)

Five hundred sixteen consecutive ICSI cycles. Only couples affected by severe male factor infertility were excluded.

INTERVENTION(S)

A total of 1,191 metaphase II (MII) oocytes (1-3 per patient) were randomly selected from the cohort of oocytes obtained from each patient and evaluated for morphologic appearance.

MAIN OUTCOME MEASURE(S)

Fertilization, pronuclear morphology, embryo quality, pregnancy rate.

RESULT(S)

There was a presence of vacuoles, abnormal I polar body, and large perivitelline space related to a lower fertilization rate. Pronuclear morphology was effected by the presence of a large perivitelline space, diffused cytoplasmic granularity, and/or centrally located granular area. The latter characteristic also negatively related to day 2 embryo quality. According to the odds ratios obtained for each oocyte morphotype to reach at least one outcome, an MII oocyte morphologic score (MOMS) was calculated. A significant relationship was found between MOMS and female age, female basal FSH, and clinical outcome.

CONCLUSION(S)

Morphologic evaluation before ICSI helps to identify MII oocytes with higher developmental potential.