Is oocyte morphology prognostic of embryo developmental potential after ICSI?

The Relationship Between Smooth Endoplasmic Reticulum Clusters in Metaphase II Oocytes and Embryological and Birth Outcomes in Infertile Couples

Background

To assess the relationship between oocytes with smooth endoplasmic reticulum cluster (SERc) and embryological and birth outcomes in infertile couples.

Methods

This was a descriptive study that included 231 infertile patients undergoing in vitro fertilization (IVF) with a total of 2447 mature oocytes (MII), of which 279 oocytes with SERc(+) from 100 patients, the remaining 2168 oocytes with SERc(-). Oocytes were evaluated for the presence or absence of the SERc simultaneously with intracytoplasmic sperm injection at 200x magnification using inverted microscopy - Observe D1.

Results

The mean age of patients was 32.05 ± 5.56 years. One hundred patients had at least one SERc(+) oocyte (with 279 SERc(+) and 956 SERc(-) oocytes). One hundred and thirty-one patients had 1212 SERc(-) oocytes. Fertilization outcomes and the rates of good-quality embryos on day 2 and day 5 did not differ between the SERc(+) and the SERc(-) groups. In the first frozen embryo transfer cycles, the clinical pregnancy rate in the group of patients with SERc(+) was not different with the SERc(-) group (61.1% vs 48.78%, p = 0.074, respectively). The live birth rate in the SERc(+) group was statistically significantly higher than the SERc(-) group (57.7% vs 43.9%, p = 0.045, respectively).

Conclusion

The fertilization rate, the quality of embryos on days 2 and 5 from oocytes with SERc(+) are similar to those with SERc(-). The live birth rate in the patients with SERc(+) group is statistically significantly higher than the SERc(-) group. There is no difference in clinical pregnancy rate between patients with and without SERc. Therefore, the exclusion of oocytes with SERc should not be recommended.

An artificial intelligence tool predicts blastocyst development from static images of fresh mature oocytes

RESEARCH QUESTION

Can a deep learning image analysis model be developed to assess oocyte quality by predicting blastocyst development from images of denuded mature oocytes?

DESIGN

A deep learning model was developed utilizing 37,133 static oocyte images with associated laboratory outcomes from eight fertility clinics (six countries). A subset of data (n = 7807) was allocated to test model performance. External model validation was conducted to assess generalizability and robustness on new data (n = 12,357) from two fertility clinics (two countries). Performance was assessed by calculating area under the curve (AUC), balanced accuracy, specificity and sensitivity. Subgroup analyses were performed on the test dataset for age group, male factor and geographical location of the clinic. Model probabilities of the external dataset were converted to a 0-10 scoring scale to facilitate analysis of correlation with blastocyst development and quality.

RESULTS

The deep learning model demonstrated AUC of 0.64, balanced accuracy of 0.60, specificity of 0.55 and sensitivity of 0.65 on the test dataset. Subgroup analyses displayed the highest performance for age group 38-39 years (AUC 0.68), a negligible impact of male factor, and good model generalizability across geographical locations. Model performance was confirmed on external data: AUC of 0.63, balanced accuracy of 0.58, specificity of 0.57 and sensitivity of 0.59. Analysis of the scoring scale revealed that higher scoring oocytes correlated with higher likelihood of blastocyst development and good-quality blastocyst formation.

CONCLUSION

The deep learning model showed a favourable performance for the evaluation of oocytes in terms of competence to develop into a blastocyst, and when the predictions were converted into scores, they correlated with blastocyst quality. This represents a significant first step in oocyte evaluation for scientific and clinical applications.

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.

Clinical and laboratory factors associated with the presence of dysmorphic oocytes in intracytoplasmic sperm injection cycles

OBJECTIVE

This study investigated the clinical and laboratory factors associated with the presence of dysmorphic oocytes in intracytoplasmic sperm injection (ICSI) cycles.

METHODS

The study involved 200 ICSI cycles, performed from 2020 to 2021, that yielded at least one mature oocyte. Clinical characteristics and ovarian stimulation methods were compared between 68 cycles with at least one dysmorphic oocyte (the dysmorphic group) and 132 cycles with normal-form oocytes only (the non-dysmorphic group). Dysmorphic oocytes were characterized by dark cytoplasm, cytoplasmic granularity, cytoplasmic vacuoles, refractile bodies in the cytoplasm, smooth endoplasmic reticulum in the cytoplasm, an oval shape, an abnormal zona pellucida, a large perivitelline space, debris in the perivitelline space, or an abnormal polar body.

RESULTS

The ages of the women, indications for in vitro fertilization, serum anti-Müllerian hormone levels, and rates of current ovarian endometrioma were similar between the dysmorphic and non-dysmorphic groups. In both groups, the three ovarian stimulation regimens, two types of pituitary suppression, and total gonadotropin dose were employed similarly. However, the dual-trigger method was used more frequently in the dysmorphic group (67.6% vs. 50%, p=0.024). The dysmorphic group contained significantly more immature oocytes and exhibited significantly lower oocyte maturity (50% vs. 66.7%, p=0.001) than the non-dysmorphic cycles. Within the dysmorphic group, significantly lower oocyte maturity was found in the cycles using a dual-trigger, but not in those with a human chorionic gonadotropin trigger.

CONCLUSION

ICSI cycles with dysmorphic oocytes are closely associated with reduced oocyte maturity. This association was observed exclusively in dual-trigger cycles.

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.

The impact of oocyte central granularity on ICSI practice: developmental competence of dysmorphic and morphologically normal companion oocytes

PURPOSE

To assess the effects of oocyte central granularity and its underlying endocrine environment on developmental competence of dysmorphic and morphologically normal oocytes.

METHODS

Retrospective cohort study including 1,082 patients undergoing autologous ICSI cycles. Of these, 211 patients provided 602 oocytes with central granularity (CG) and 427 morphologically normal cycle companion oocytes (NCG). The remaining 871 patients provided only morphologically normal oocytes in cycles not yielding dysmorphic oocytes (N). Patient profile associated with CG was characterized, and fertilization rates, early morphokinetics and live birth rates were compared between N, CG and NCG groups. Patient characteristics associated with implantation and delivery performance of CG-derived embryos were assessed.

RESULTS

CG was associated with higher maternal age, basal FSH concentrations and total FSH dose, but with lower circulating AMH (p ≤ 0.035). Fertilization rates were reduced and early morphokinetic parameters were delayed in CG (p < 0.025) and NCG (p < 0.05) groups as compared to the N group. Embryos derived from CG oocytes achieved a markedly lower live birth rate (14.9%) as compared to those derived from NCG (36.8%; p = 0.03) and N oocytes (29.8%; p = 0.002). The negative relationship between CG and live birth was confirmed by a multivariate analysis controlling for potential confounders (OR:2.59, IC:1.27-5.31; P = 0.009). Implantation and delivery rates following transfers of CG-derived embryos were inversely associated with maternal age.

CONCLUSION

CG oocytes, but not their morphologically normal cycle companions, have severely compromised developmental competence. Maternal age should be a key parameter in deciding whether or not to utilize CG oocytes in ICSI cycles.

Human oocytes image classification method based on deep neural networks

BACKGROUND

The effectiveness of in vitro fertilization depends on the assessment and selection of oocytes and embryos with the highest developmental potential. One of the tasks in the ICSI (intracytoplasmic sperm injection) procedure is the classification of oocytes according to the stages of their meiotic maturity. Oocytes classification traditionally is done manually during their observation under the light microscope. The paper is part of the bigger task, the development of the system for optimal oocyte and embryos selection. In the hereby work, we present the method for the automatic classification of oocytes based on their images, that employs DNN algorithms.

RESULTS

For the purpose of oocyte class determination, two structures based on deep neural networks were applied. DeepLabV3Plus was responsible for the analysis of oocyte images in order to extract specific regions of oocyte images. Then extracted components were transferred to the network, inspired by the SqueezeNet architecture, for the purpose of oocyte type classification. The structure of this network was refined by a genetic algorithm in order to improve generalization abilities as well as reduce the network's FLOPs thus minimizing inference time. As a result, [Formula: see text] at the level of 0.964 was obtained at the level of the validation set and 0.957 at the level of the test set. Generated neural networks as well as code that allows running the processing pipe were made publicly available.

CONCLUSIONS

In this paper, the complete pipeline was proposed that is able to automatically classify human oocytes into three classes MI, MII, and PI based on the oocytes' microscopic image.

Aging and oocyte competence: A molecular cell perspective

Follicular microenvironment is paramount in the acquisition of oocyte competence, which is dependent on two interconnected and interdependent processes: nuclear and cytoplasmic maturation. Extensive research conducted in human and model systems has provided evidence that those processes are disturbed with female aging. In fact, advanced maternal age (AMA) is associated with a lower chance of pregnancy and live birth, explained by the age-related decline in oocyte quality/competence. This decline has largely been attributed to mitochondria, essential for oocyte maturation, fertilization, and embryo development; with mitochondrial dysfunction leading to oxidative stress, responsible for nuclear and mitochondrial damage, suboptimal intracellular energy levels, calcium disturbance, and meiotic spindle alterations, that may result in oocyte aneuploidy. Nuclear-related mechanisms that justify increased oocyte aneuploidy include deoxyribonucleic acid (DNA) damage, loss of chromosomal cohesion, spindle assembly checkpoint dysfunction, meiotic recombination errors, and telomere attrition. On the other hand, age-dependent cytoplasmic maturation failure is related to mitochondrial dysfunction, altered mitochondrial biogenesis, altered mitochondrial morphology, distribution, activity, and dynamics, dysmorphic smooth endoplasmic reticulum and calcium disturbance, and alterations in the cytoskeleton. Furthermore, reproductive somatic cells also experience the effects of aging, including mitochondrial dysfunction and DNA damage, compromising the crosstalk between granulosa/cumulus cells and oocytes, also affected by a loss of gap junctions. Old oocytes seem therefore to mature in an altered microenvironment, with changes in metabolites, ribonucleic acid (RNA), proteins, and lipids. Overall, understanding the mechanisms implicated in the loss of oocyte quality will allow the establishment of emerging biomarkers and potential therapeutic anti-aging strategies. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology.

All that glitters is not gold: a stereological study of human donor oocytes

Here we report a quantitative analysis of human metaphase II (MII) oocytes from a 22-year-old oocyte donor, retrieved after ovarian-controlled hyperstimulation. Five surplus donor oocytes were processed for transmission electron microscopy (TEM), and a stereological analysis was used to quantify the distribution of organelles, using the point-counting technique with an adequate stereological grid. Comparisons between means of the relative volumes (Vv) occupied by organelles in the three oocyte regions, cortex (C), subcortex (SC) and inner cytoplasm (IC), followed the Kruskal-Wallis test and Mann-Whitney U-test with Bonferroni correction. Life cell imaging and TEM analysis confirmed donor oocyte nuclear maturity. Results showed that the most abundant organelles were smooth endoplasmic reticulum (SER) elements (26.8%) and mitochondria (5.49%). Significant differences between oocyte regions were found for lysosomes (P = 0.003), cortical vesicles (P = 0.002) and large SER vesicles (P = 0.009). These results were quantitatively compared with previous results using prophase I (GV) and metaphase I (MI) immature oocytes. In donor MII oocytes there was a normal presence of cortical vesicles, SER tubules, SER small, medium and large vesicles, lysosomes and mitochondria. However, donor MII oocytes displayed signs of cytoplasmic immaturity, namely the presence of dictyosomes, present in GV oocytes and rare in MI oocytes, of SER very large vesicles, characteristic of GV oocytes, and the rarity of SER tubular aggregates. Results therefore indicate that the criterion of nuclear maturity used for donor oocyte selection does not always correspond to cytoplasmic maturity, which can partially explain implantation failures with the use of donor oocytes.

Identification of significant imaging features for sensing oocyte viability

The evaluation of oocyte viability in the laboratory is limited to the morphological assessment by naked eyes, but the realization that most normal-appearing oocytes may conceal abnormalities prompts the search for automated approaches that can detect the abnormalities imperceptible to naked eyes. In this study, we developed an image processing pipeline applicable to bright-field microscope images to quantify the causal relationship between the quantitative imaging features and the developmental potential of oocytes. We acquired 19 imaging features of approximately 700 oocytes and determined two imaging subtypes, namely viable and nonviable subtypes that correlated closely with a viability fluorescence indicator and cleavage rates. The causal relationship between these imaging features and oocyte viability was derived from a viability-oriented Bayesian network that was developed based on the Bayesian information criterion and Tabu search. Our experimental results revealed that entropy with mean Gray Level Co-Occurrence Matrix energy describing the uniformity and texture roughness of cytoplasm were salient features for the automated selection of promising oocytes that exhibited excellent developmental potential.

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.

Oocyte quality in assisted reproduction techniques

The metaphase II (MII) oocyte is the mature female gamete, produced from a complex maturation process called oogenesis that starts in the first weeks of embryogenesis in the female embryo tract, continues during puberty, and is completed at fertilization with the spermatozoon. Oogenesis is closely related to folliculogenesis. In assisted reproduction techniques, oocytes are retrieved in cumulus-oocyte complexes after ovarian stimulation. Before being used for in vitro fertilization or cryopreservation, the metaphase (MII) oocytes can be classified according to different morphological traits and by the presence/absence of the meiotic spindle. Except for a few and rare morphological characteristics that make the oocyte discarded, none of the morphological characteristics is predictive of oocyte competence in giving a viable embryo. On the other side, specific key performance indicators based on MII oocytes test the efficacy of in vitro treatments. Molecular, cellular, or genetic abnormalities in the oocytes have observable consequences on the embryo development dynamics and its genetic content. Besides what can be seen in vitro, several intrinsic and extrinsic factors related to the patient are responsible for the oocyte quality. The clinician and the patient herself must be aware of these factors to preserve the reproductive functions as much as possible. In the present review, we have revised oogenesis and the role of mature oocytes in supporting the fertilization process and early embryo development; we have also listed the oocyte morphological traits and key performance indicators related to the oocyte quality and studied the intrinsic and extrinsic factors that irreversibly impact female fertility.

Oocyte quality and embryo selection strategies: a review for the embryologists, by the embryologists

With the advance of assisted reproduction techniques, and the trend towards blastocyst culture and single embryo transfer, gamete and embryo assessment have gained greater importance in ART treatment. Embryo quality depends mainly on gamete quality and culture conditions. Oocyte maturity identification is necessary in order to plan fertilization timing. Mature oocytes at the metaphase II stage show a higher fertilization rate compared to immature oocytes. Morphology assessment is a critical yet challenging task that may serve as a good prognostic tool for future development and implantation potential if done effectively. Various grading systems have been suggested to assess embryos at pronuclear, cleavage, and blastocyst stages. By identifying the embryo with the highest implantation potential, it is possible to reduce the number of embryos transferred without compromising the chances of a successful pregnancy. Apart from the conventional morphology assessment, there are several invasive or non-invasive methods for embryo selection such as preimplantation genetic testing, morphokinetics, proteomics, metabolomics, oxygen consumption, and measurement of oxidative stress in culture medium. Morphokinetics is a method based on time-lapse technology and continuous monitoring of embryos. In this review, we aim to describe and compare the most effective and widely used methods for gamete and embryo assessment as well as embryo selection.

Polycystic ovary syndrome phenotype does not have impact on oocyte morphology

PURPOSE

The primary objective of the present study of women participating in an ICSI program was to determine whether the morphologic quality of oocytes was related to the polycystic ovary syndrome (PCOS) phenotype.

METHODS

We performed a retrospective cohort study in the IVF unit at the Lille University Medical Center (Lille, France) between 2006 and 2015. Oocyte morphology (fragmented first polar body, abnormal zona pellucida, large perivitelline space, material in perivitelline space, abnormal shape of oocyte, granular cytoplasm and intracytoplasmic vacuoles) was evaluated in PCOS women and according to different subgroup (depending on the presence or absence of the cardinal features polycystic ovarian morphology (PCOM), hyperandrogenism (HA), and oligo-anovulation (OA)).

RESULTS

A total of 1496 metaphase II oocytes (n = 602 for phenotype A combining PCOM + HA + OA, n = 462 oocytes for phenotype C: PCOM + HA, and n = 432 for phenotype D: PCOM + OA) were assessed. The phenotypes A, C and D did not differ significantly with regard to the proportion of normal oocytes (adjusted percentages (95%CI): 35.2% (31.5 to 39.1%), 25.8% (21.9 to 29.9%) and 34.0% (29.7 to 38.6%), respectively: adjusted p = 0.13). Likewise, there were no significant intergroup differences in oocyte morphology. The ICSI outcome was not significantly associated with the PCOS phenotype.

CONCLUSION

The present study is the first to show that the PCOS phenotype (notably the presence vs. absence of OA and/or HA) is not significantly associated with the morphological quality of oocytes.

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.

Oocytes With Smooth Endoplasmic Reticulum Aggregates May Not Impact Blastocyst Euploidy Rate

OBJECTIVE

To investigate whether the euploidy rate of blastocysts derived from smooth endoplasmic reticulum aggregates (SERa) positive cycles and oocytes are impacted.

DESIGN

Retrospective cohort study.

METHODS

A total of 601 preimplantation genetic testing (PGT) cycles with at least one oocyte retrieved in our center between April 2017 and May 2021 were initially included in the study. Women>35 years and PGT cycles with chromosomal structural rearrangements (PGT-SR) were excluded. Embryological and blastocyst ploidy outcomes were compared among SERa+ oocyte, sibling SERa- oocytes and oocytes in SERa- cycles.

RESULTS

No significant difference was observed among the SERa+ oocyte group, sibling SERa- oocyte group, and SERa- cycle group in the normal fertilization rate (82.1% vs. 77.8% vs. 83.1%, respectively, P=0.061), blastocyst formation rate (71.0% vs. 72.5% vs. 68.4%, respectively, P=0.393), good quality blastocyst formation rate (46.4% vs. 48.3% vs. 42.6%, respectively, P=0.198). No significant difference was observed in the euploidy rate (50.0% vs. 62.5% vs. 63.3%, respectively, P=0.324), mosaic rate (12.5% vs. 9.7% vs. 13.4%, respectively, P=0.506), and aneuploidy rate (37.5% vs. 27.8% vs. 23.2%, respectively, P=0.137) among the three groups.

CONCLUSION

Our results suggest that the euploidy rate of blastocysts derived from SERa+ cycles and oocytes may not be impacted.

Vacuolization in embryos on days 3 and 4 of in vitro development: Association with stimulation protocols, embryo development, chromosomal status, pregnancy and neonatal outcomes

STUDY QUESTION

Is vacuolization in embryos on Days 3 and 4 associated with parent-related factors, stimulation protocols, embryo development, embryo ploidy, pregnancy and neonatal outcomes?

STUDY DESIGN SIZE DURATION

This is a retrospective cohort study that comprised 5,703 embryos from 611 patients who underwent preimplantation genetic testing and time-lapse monitoring of their embryos from August 2017 to September 2021.

MAIN RESULTS

Embryo vacuolization on Days 3 and 4 is associated with the LH level on the day of the hCG trigger and the number of retrieved oocytes. Compared to vacuole-negative embryos, the rates of blastocyst formation and good-blastocyst formation was significantly lower in vacuole-positive embryos. We observed no significant difference in the rates of euploidy, implantation, ongoing pregnancy, and live birth between vacuole-positive and vacuole-negative embryos. In vacuole-positive embryos, the embryos of which the vacuole-positive blastomeres were involved in embryo compaction exhibited significantly higher mosaicism rate compared with those of which the vacuole-positive blastomeres were not involved in embryo compaction.

CONCLUSION

Vacuolization in embryos on Days 3 and 4 is associated with reduced blastocyst formation rate and high-quality blastocyst rate. Blastocysts had a low mosaicism rate if the vacuole-containing cells were rejected in compaction process, which supports the hypothesis that exclusion of abnormal blastomeres from compaction is a self-correction mechanism.

Growth hormone in fertility and infertility: Mechanisms of action and clinical applications

Secreted by the anterior pituitary gland, growth hormone (GH) is a peptide that plays a critical role in regulating cell growth, development, and metabolism in multiple targeted tissues. Studies have shown that GH and its functional receptor are also expressed in the female reproductive system, including the ovaries and uterus. The experimental data suggest putative roles for GH and insulin-like growth factor 1 (IGF-1, induced by GH activity) signaling in the direct control of multiple reproductive functions, including activation of primordial follicles, folliculogenesis, ovarian steroidogenesis, oocyte maturation, and embryo implantation. In addition, GH enhances granulosa cell responsiveness to gonadotropin by upregulating the expression of gonadotropin receptors (follicle-stimulating hormone receptor and luteinizing hormone receptor), indicating crosstalk between this ovarian regulator and the endocrine signaling system. Notably, natural gene mutation of GH and the age-related decline in GH levels may have a detrimental effect on female reproductive function, leading to several reproductive pathologies, such as diminished ovarian reserve, poor ovarian response during assisted reproductive technology (ART), and implantation failure. Association studies using clinical samples showed that mature GH peptide is present in human follicular fluid, and the concentration of GH in this fluid is positively correlated with oocyte quality and the subsequent embryo morphology and cleavage rate. Furthermore, the results obtained from animal experiments and human samples indicate that supplementation with GH in the in vitro culture system increases steroid hormone production, prevents cell apoptosis, and enhances oocyte maturation and embryo quality. The uterine endometrium is another GH target site, as GH promotes endometrial receptivity and pregnancy by facilitating the implantation process, and the targeted depletion of GH receptors in mice results in fewer uterine implantation sites. Although still controversial, the administration of GH during ovarian stimulation alleviates age-related decreases in ART efficiency, including the number of oocytes retrieved, fertilization rate, embryo quality, implantation rate, pregnancy rate, and live birth rate, especially in patients with poor ovarian response and recurrent implantation failure.

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.

DYSMORPHISMS OF OOCYTES IN ART PROCEDURES. LITERATURE REVIEW

Currentliterature review presents the analysis of results of studies of morphological qualities and anomalies (dysmorphisms) of human oocytes in the field of assisted reproductive technologies. The variety of intracytoplasmic anomalies encountered in the clinical practice of in vitro fertilization, their effect on fertilization, cleavage, implantation frequency, clinical pregnancy rate were described. Moreover, the morphological characteristics of oocyte could be considered to use as biomarkers in predicting the quality of embryos and blastocysts, and further implantation potential.

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.

Analysis of Morphokinetic Parameters of Feline Embryos Using a Time-Lapse System

Simple Summary

This study was conducted with the aim of analyzing the morphokinetic parameters that determine the proper development of feline embryos in vitro. Our research was carried out using a time-lapse monitoring system shows that the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

Abstract

The aim of this study was to analyze the morphokinetic parameters of feline embryos using a time lapse system. Oocytes matured in vitro were fertilized (IVF) and in vitro cultured in a time lapse-system (Primo Vision^®, Gothenburg, Sweden). The first cell division of embryos occurred between 17 h post insemination (hpi) and 38 hpi, with the highest proportion of embryos (46%) cleaving between 21 and 24 hpi. The timing of the first cleavage significantly affected further embryo development, with the highest development occurring in embryos that cleaved at 21–22 hpi. Embryos that cleaved very early (17–18 hpi) developed poorly to the blastocyst stage (2%) and none of the embryos that cleaved later than 27 hpi were able to reach the blastocyst stage. Morphological defects were observed in 48% of the embryos. There were no statistically significant differences between the timing intervals of the first cleavage division and the frequency of morphological defects in embryos. Multiple (MUL) morphological defects were detected in more than half (56%) of the abnormal embryos. The most frequent single morphological defects were cytoplasmic fragmentation (FR) (8%) and blastomere asymmetry (AS) (6%). Direct cleavage (DC) from 1–3 or 3–5 blastomeres, reverse cleavage (RC) and vacuoles were rarely observed (2–3%). The timing of blastocyst cavity formation is a very good indicator of embryo quality. In our study, blastocyst cavity formation occurred between 127–167 hpi, with the highest frequency of hatching observed in blastocysts that cavitated between 142–150 hpi. Blastocysts in which cavitation began after 161 h did not hatch. In conclusion, the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

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.

Oocytes With Smooth Endoplasmic Reticulum Aggregates Are Not Associated With Impaired Reproductive Outcomes: A Matched Retrospective Cohort Study

OBJECTIVE

To investigate whether the reproductive outcomes of oocytes with smooth endoplasmic reticulum aggregates (SERa) are impaired.

METHODS

A total of 2893 intracytoplasmic sperm injection (ICSI) cycles were performed between January 2010 and December 2019 in our center. In 43 transfer cycles, transferred embryos were totally derived from SERa+ oocytes. Each of the 43 cycles was matched with a separate control subject from SERa- patient of the same age ( ± 1 year), embryo condition, main causes of infertility, type of protocols used for fresh or frozen embryo transfer cycles. The clinical pregnancy, implantation, ectopic pregnancy and live birth rate were compared between the two groups.

RESULTS

43 embryo transfer cycles from SERa- patient were matched to the 43 transferred cycles with pure SERa+ oocytes derived embryos. No significant difference was observed in clinical pregnancy rate (55.81% vs. 65.11%, p=0.5081), implantation rate (47.89% vs. 50.70%, p=0.8667) and live birth rate (48.84% vs. 55.81%, p=0.6659) between the SERa+ oocyte group and the matched group. No congenital birth defects were found in the two groups.

CONCLUSION

Our results suggest that the implantation, clinical pregnancy, live birth and birth defects rate of embryos derived from oocytes with SERa are not impaired.

Degenerative Oocytes in the Aspirated Cohort Are Not Due to the Aspirating Needle: a Prospective Randomized Pilot Study with Sibling Oocytes

The aim of this study is to compare two different needles (17G vs. 20-17G variable diameter) used for OPU and to assess whether the different stress forces along the needle affect the presence of degenerative oocytes, oocyte quality, and embryo morphokinetics. Prospective, randomized study enrolled women undergoing in vitro fertilization (IVF) intracytoplasmic sperm injection (ICSI) from August 2016 through August 2018 in an IVF unit at a tertiary care medical center. Ovaries were randomly aspirated using either a 20-17G needle or a 17G needle. The embryologist was blinded to the aspirating needle and sibling oocytes were separated according to needle used for fertilization and further evaluation. Oocytes were scored negatively if one of the following parameters was abnormal immediately after OPU: polar body shape, zona pellucida, cytoplasm, perivitelline space, or vacuoles. The presence of degenerative oocytes was noted at OPU. A total of 580 oocytes from 43 women were evaluated, 293 in the 17G needle group and 287 in the 20-17G group. Oocyte scoring was comparable between the two different needles (- 1.99 ± 1.9 vs. - 1.88 ± 1.69; P = 0.13), as were embryo quality and pregnancy rate. Cohorts with degenerative oocytes had lower oocyte scores (- 2.11 ± 1.81 vs. - 1.60 ± 1.50; P = 0.001) and poorer performance and fertilization rates (62.5% vs. 78.5%; P < 0.001) than did cohorts with no degenerative oocytes. Cycles with degenerative oocytes in the cohort at OPU demonstrated poorer oocyte quality and decreased fertilization, regardless of the needle used. 1.5.2016 NIH number NCT02749773.

Degenerated oocyte in the cohort adversely affects IVF outcome

The presence of Degenerated Oocyte (DEG) was mostly described after intracytoplasmic sperm injection (ICSI), with fewer reports on DEG at the time of ovum pick-up (OPU). This study aims to assess morphokinetics of embryos cultured in a time-lapse incubator and compare cohorts with and without DEG at OPU. In a retrospective cohort study from January 1, 2016 until September 31, 2017 a total of 399 IVF/ICSI cycles and 2980 embryos were evaluated. In 81 of 399 cycles at least one DEG oocyte was observed at the time of OPU. The remaining 318 cycles with no DEG oocyte were compared as a control group. In the DEG group, significantly more oocytes were collected per patient (12.9 ± 7.2 vs. 10.1 ± 6.1. P < 0.001). Fertilization rate, pregnancy and clinical pregnancy rates were comparable between the two groups, however, the morphokinetics and developmental scores of the embryos were significantly worse in the DEG group, (KID 3.4 ± 1.6 vs. 3.2 ± 1.6 P = 0.002 and ESHRE 1.5 ± 1.1 vs. 1.4 ± 1.0 P = 0.046). Significantly more patients achieved top-quality embryos in the NON DEG group (58.8% vs. 53.0%, P = 0.03), however, comparable delivery rate was achieved in both groups. In the DEG group, the frequency of DEG oocyte per cycle was negatively correlated with pregnancy rate. GnRH agonist protocol and the 17-20G needle used for OPU were significant predictors for the presence of DEG oocyte at OPU. In conclusions DEG oocyte may negatively affect IVF outcome, however, younger patients, and significantly more oocytes collected in the DEG group compensate for the IVF results.

Selection of competent oocytes by morphological criteria for assisted reproductive technologies

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

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.

Role of diagnostic intracytoplasmic sperm injection (ICSI) in the management of genetically determined zona pellucida-free oocytes during in vitro fertilization: a case report

PURPOSE

To report the utilization of diagnostic intracytoplasmic sperm injection (D-ICSI), an ICSI cycle performed in the natural cycle, to obtain information about embryo development potential after sperm injection into zona pellucida (ZP)-free oocytes.

MATERIALS AND METHODS

We report the case of a couple with primary unexplained infertility with a history of previous failed, in vitro fertilization intracytoplasmic sperm injection (IVF-ICSI) cycles characterized by the presence of ZP-free oocytes. Whole exome sequencing (WES) was carried out to analyse the possible genetic basis of oocyte abnormality.

RESULTS

Diagnostic ICSI provided information about the embryo development potential from ZP-free oocytes and allowed better planning of the subsequent ICSI cycle. WES revealed that the absence of ZP was likely to be due to a new (ZP1) mutation. The subsequent ICSI cycle resulted in the delivery of a healthy baby.

DISCUSSION

To the best of our knowledge, our report is the first to describe the use of D-ICSI to determine the feasibility of embryo development and implantation in a patient with ZP1 mutation, resulting in the subsequent delivery of a healthy baby. We used 'diagnostic' ICSI in the normal menstrual cycle to explore the feasibility of embryo development after sperm injection into ZP-free oocytes. Our results may expand the spectrum of diagnostic procedures associated with unexplained infertility.

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.

Using Time Lapse Monitoring for Determination of Morphological Defect Frequency in Feline Embryos after In Vitro Fertilization (IVF)

Simple Summary

This study was conducted with the aim of determining the frequency of morphological defects in feline embryos, their competence to reach the blastocyst stage, and their ability to hatch. Embryonic morphological disorders affect development potential, and the use of time lapse monitoring (TLM) guarantees the precise observation of any changes that occur during in vitro embryo development.

Abstract

Some human, bovine, and mouse in vitro fertilized (IVF) embryos with morphokinetic abnormalities such as fragmentation, direct cleavage, and cytoplasmic vacuoles have the potential to reach the blastocyst stage, which is related to a high potential for implantation. The latest techniques of embryo development observation to enable the evaluation and selection of embryos are based on time lapse monitoring (TLM). The aim of this study was to determine the frequency of morphological defects in feline embryos, their competence to reach the blastocyst stage, and their ability to hatch. Oocyte-cumulus complexes were isolated after the scarification of ovaries and matured in vitro. Matured oocytes were fertilized in vitro by capacitated spermatozoa. Randomly selected oocytes were observed by TLM for seven-to-eight days. Out of 76 developed embryos, 41 were morphologically normal, of which 15 reached the blastocyst stage. Of 35 abnormally developed embryos, 17 reached the blastocyst stage, of which six had single aberrations and 11 had multiple aberrations. The hatching rate (%) was 15.6% in normally cleaving embryos, 6.25% in embryos with single aberrations, and 3.33% in those with multiple aberrations. The present study reports the first results, found by using TLM, about the frequency of the morphological defects of feline embryos, their competence to reach the blastocyst stage, and their ability to hatch.

Artificial oocyte activation with SrCl2 or calcimycin after ICSI improves clinical and embryological outcomes compared with ICSI alone: results of a randomized clinical trial

STUDY QUESTION

Are pregnancy and birth rates affected by artificial oocyte activation (AOA) with SrCl2 or calcimycin after ICSI for couples with male-factor infertility linked to abnormal sperm morphology or for couples with previous ICSI cycles of unexplained low fertilization or inadequate fertilization associated with impaired oocyte morphology?

SUMMARY ANSWER

AOA with either SrCl2 or calcimycin can improve the rates of clinical pregnancy, ongoing pregnancy and live birth compared with ICSI alone, and the two agents have diverse effects for different subgroups of patients.

WHAT IS KNOWN ALREADY

ICSI is a successful treatment for infertility, but not in all individuals. AOA has potential to overcome inadequate fertilization in ICSI. Calcimycin and SrCl2 are candidate agents for AOA, but their effectiveness remains to be compared.

STUDY DESIGN, SIZE, DURATION

This study was a randomized, open-label, three-arm, parallel-group, double-centre, superiority trial conducted between April 2015 and January 2016. The study evaluated the effects of AOA with calcimycin or SrCl2 for clinical pregnancy rates after ICSI and included 343 couples divided into three groups.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Couples were included if they had two previous ICSI cycles of no or low fertilization (0-30%) with unknown causes or impaired oocyte morphology. Male-factor infertility cycles (frozen-thawed sperm, surgically retrieved sperm or ejaculates contained <10 millions spermatozoa/ml) undergoing their first ICSI attempt were also included if they had 100% abnormal sperm morphology (including globozoospermia and tapered-head). Couples were randomized to undergo ICSI with SrCl2 AOA, ICSI with calcimycin AOA or ICSI alone, with clinical pregnancy as the primary endpoint. Effect sizes were summarized as absolute rate differences (ARDs) and odds ratios (ORs), with precision evaluated by 95% CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

Both SrCl2 and calcimycin AOA improved clinical pregnancy rates compared to ICSI alone (49, 42 and 27%; ARD 22, 95% CI: 9-33; P = 0.0007 and ARD 16, 95% CI: 3-27; P = 0.014). SrCl2 and calcimycin AOA were also superior to ICSI alone on the rates of ongoing pregnancy (42, 36 and 23%; P = 0.0019 and P = 0.023) and live birth (40, 33 and 18%; P = 0.0002 and P = 0.012). Among couples with previous ICSI cycles of low fertilization, AOA with SrCl2 (but not with calcimycin) was superior to ICSI alone for rates of clinical pregnancy (ARD 35 percentage points (pp), P = 0.0007), ongoing pregnancy (ARD 27 pp, P = 0.009) and live birth (ARD 37 pp, P = 0.002). Among couples affected by male-factor infertility, AOA with calcimycin (but not with SrCl2) was superior to ICSI alone for rates of clinical pregnancy (ARD 22 pp, P = 0.006), ongoing pregnancy (ARD 19 pp, P = 0.013) and live birth (ARD 17 pp, P = 0.02).

LIMITATIONS, REASONS FOR CAUTION

This study was an open-label trial, and this design might have introduced bias, although randomization methods were used. The study did not include a longitudinal follow-up, so further evidence is required to demonstrate the safety of AOA.

WIDER IMPLICATIONS OF THE FINDINGS

The decision to use SrCl2 or calcimycin for AOA after ICSI may depend on whether the activation failure originates in the oocyte or the sperm.

STUDY FUNDING/COMPETING INTEREST(S)

The study received no funding and the authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

NCT02424214.

TRIAL REGISTRATION DATE

22 April 2015.

DATE OF FIRST PATIENT’S ENROLMENT

27 April 2015.

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.

Is perivitelline space morphology of the oocyte associated with pregnancy outcome in intracytoplasmic sperm injection cycles?

OBJECTIVE(S)

To investigate the effect of perivitelline space (PVS) abnormalities on the outcomes of intracytoplasmic sperm injection (ICSI) cycles in which the entire cohort was affected.

STUDY DESIGN

Data from 9752 oocytes obtained from 1151 ICSI cycles performed from June/2010 to August/2016 in a private university-affiliated IVF centre. Cycles were divided into four groups according to the presence or absence of PVS abnormalities: PVS-L group (cycles with the entire oocyte cohort affected by large PVS, n = 265), PVS-G group (cycles with the entire oocyte cohort affected by PVS granularity, n = 280), PVS-L + PVS-G group (cycles with the entire oocyte cohort affected by PVS-L and PVS-G, n = 204), and control group (cycles with the entire oocyte cohort free of PVS abnormalities, n = 402). The effect of PVS abnormalities on ICSI outcomes was assessed by GLM adjusted for potential confounders.

RESULTS

Groups with PVS abnormalities presented substantially higher FSH/follicle (p < 0.001) and FSH/oocyte (p < 0.001) ratios, and lower numbers of follicles (p < 0.001), oocytes (p < 0.001) and embryos (p = 0.002) compared to the control group. PVS-L + PVS-G implantation (p = 0.044) and pregnancy (p = 0.004) rates were significantly lower than in cycles with isolated PVS abnormalities and controls.

CONCLUSION(S)

Cycles in which the entire oocyte cohort is affected by both large PVS and PVS granularity have compromised implantation and pregnancy rates.

Influence of the type of semen and morphology of individual sperm cells on the results of ICSI in domestic cats

The aim of this study was to analyze the influence of the type of spermatozoa and of different sperm abnormalities on fertilization and embryo development after ICSI in cats. In Exp I, ICSI was performed using urethral or epididymal spermatozoa collected from 7 tomcats. In Exp. II, epididymal spermatozoa from 16 cats were used for ICSI and an epididymal spermatozoon exhibiting no abnormalities or one with an abnormality was microinjected into an oocyte. Exp. I was performed in 14 replicates and Exp. II was performed in 20 replicates. In both experiments the number of cleaved oocytes, the number of embryos at the morula stage and the number of embryos at the blastocyst stage were evaluated at 24 h, and at 6 and 7 days after ICSI, respectively, and compared between experimental groups. No statistically significant differences (P > 0.05) were observed, either for Exp. I or for Exp. II. The average cleavage rate was 60.2%, morula rate 62.3% and blastocyst rate 19.2% in Exp. I and 51.6%, 66.8% and 25.8% in Exp. II, respectively. The study confirmed that both urethral and epididymal spermatozoa can be used for in vitro fertilization in cats and proved the usefulness of the ICSI method in the case of teratozoospermic males. The study showed that even in severe cases, when almost no normal spermatozoa can be found in the semen, it is possible to obtain embryos using abnormal sperm cells with the same chance of success as for normal spermatozoa.

Morphometric analysis of human oocytes using time lapse: does it predict embryo developmental outcomes?

The aim of this prospective study was to evaluate the relationship between morphometric parameters of metaphase II (MII) oocytes and the morphokinetic behaviour of subsequent embryos derived by intra-cytoplasmic sperm injection (ICSI). The association between oocyte morphometry: (whole oocyte), ooplasm, width of zona pellucida (ZP) and perivitelline space (PVS) and first polar body (PB) with embryo morphokinetic variables, including time of second PB extrusion (tPB2), pronuclei appearance (tPN), pronuclei fading (tPNf), formation of two to eight cells (t2 to t8) and irregular cleavage events [uneven at two cells stage, cell fusion (Fu) and trichomonas mitoses (TM)] were assessed. tPB2, t5 and t8 timings were related to the ooplasm diameter (p = 0.003, r = -0.12; p = 0.001, r = -0.16; p < 0.001 r = -0.36, respectively); otherwise, there were no significant relationships apart from an association between the oocyte morphometry and other morphokinetic parameters, irregular cleavage embryos as well as embryo arrest which approached significance (p > 0.05). Overall, the data showed that morphometric parameters of oocytes did not provide a tool for the prediction of embryo morphokinetic or embryo selection in ICSI cycles. However, ooplasm diameter might be useful as a marker for predicting the timing of embryo cleavage.

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.

Obesity results with smaller oocyte in in vitro fertilization/intracytoplasmic sperm injection cycles-a prospective study

BACKGROUND

Obesity is associated with several fertility disorders. This prospective cohort study was designed to evaluate the effect of body mass index (BMI) (kg/m2) on oocyte diameter and treatment.

METHODS

Women undergoing in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) were enrolled in the study. They were divided into two groups according to BMI: obese (BMI > 30) and normal weight (BMI < 25). Mature oocytes were evaluated according to total diameter, zona pellucida, and oolema diameters.

RESULTS

A total of 387 oocytes were obtained from the 46 women who participated. Significantly more mature oocytes (M2) were retrieved from normal weight patients compare to obese women (15.1 ± 6.8 vs. 9.7 ± 3.9, respectively, P < 0.001). Oocytes from women in the obese group were significantly smaller than those in the normal weight group, including oocyte diameter (157.9 ± 7.9 vs. 164.3 ± 5.1 μm, P < 0.0001), oolema diameter (110.3 ± 4.5 vs. 113.5 ± 3.5 μm, P < 0.0001), and zona pellucida thickness (17.9 ± 2.6 vs. 19.0 ± 2.4 μm, P < 0.000), respectively. Multivariate logistic regression analysis, including oolema diameter, female age, BMI, number of M2 oocytes, and zona pellucida, was conducted to predict pregnancy. Small oolema diameter in obese patient adversely correlated with pregnancy. Larger oolema diameter was positively associated with the probability of pregnancy in the obese group as well as thinner zona pellucida.

CONCLUSION

Obesity is associated with smaller oocytes, which adversely affect fertility outcomes.

TRIAL REGISTRATION

NIH number NCT01672931.

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.

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.

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.

N-Acetylcysteine improves oocyte and embryo quality in polycystic ovary syndrome patients undergoing intracytoplasmic sperm injection: an alternative to metformin

Polycystic ovary syndrome (PCOS) is associated with low-quality oocytes. The aim of the present study was to investigate the effects of metformin (MET), N-acetylcysteine (NAC) and their combination on follicular fluid parameters, oocytes and embryo quality in PCOS patients. A prospective randomised placebo-controlled pilot study on 60 Iranian women with PCOS (aged 25–35 years) undergoing intracytoplasmic sperm injection (ICSI) was designed. Women were divided into four groups (n = 15 in each): (1) an MET, administered 1500 mg day–1 MET; (2) an NAC group, administered 1800 mg day–1 NAC; (3) an NAC + MET group; and (4) a placebo group. Drugs were administered from the 3rd day of previous cycle until the day of oocyte aspiration (6 weeks treatment in total). Data were analysed by one-way ANOVA, with significance set at P < 0.05. The number of immature and abnormal oocytes decreased significantly in the NAC compared with placebo group, with a concomitant increase in the number of good-quality embryos in the NAC group (P < 0.05). Malondialdehyde levels decreased significantly in the NAC and NAC + MET groups compared with the placebo-treated group (P < 0.02). In addition, there were significant decreases in leptin levels in the NAC, MET and NAC + MET groups compared with the placebo group (P < 0.001). Insulin and LH levels were significantly lower in the MET and NAC groups compared with the placebo-treated group (P < 0.02). We concluded that NAC improves oocyte and embryo quality and could be administered as an alternative to MET.

Fertilization and embryo quality of mature oocytes with specific morphological abnormalities

OBJECTIVE

To investigate fertilization and embryo quality of dysmorphic mature oocytes with specific morphological abnormalities obtained from intracytoplasmic sperm injection (ICSI).

METHODS

The fertilization rate (FR) and embryo quality were compared among 58 dysmorphic and 42 normal form oocytes (control 1) obtained from 35 consecutive ICSI cycles, each of which yielded at least one dysmorphic mature oocyte, performed over a period of 5 years. The FR and embryo quality of 441 normal form oocytes from another 119 ICSI cycles that did not involve dysmorphic oocytes served as control 2. Dysmorphic oocytes were classified as having a dark cytoplasm, cytoplasmic granularity, cytoplasmic vacuoles, refractile bodies in the cytoplasm, smooth endoplasmic reticulum in the cytoplasm, an oval shape, an abnormal zona pellucida, a large perivitelline space, debris in the perivitelline space, or an abnormal polar body (PB).

RESULTS

The overall FR was significantly lower in dysmorphic oocytes than in normal form oocytes in both the control 1 and control 2 groups. However, embryo quality in the dysmorphic oocyte group and the normal form oocyte groups at day 3 was similar. The FR and embryo quality were similar in the oocyte groups with a single abnormality and multiple abnormalities. Specific abnormalities related with a higher percentage of top-quality embryos were dark cytoplasm (66.7%), abnormal PB (50%), and cytoplasmic vacuoles (25%).

CONCLUSION

The fertilization potential of dysmorphic oocytes in our study was lower, but their subsequent embryonic development and embryo quality was relatively good. We were able to define several specific abnormalities related with good or poor embryo quality.

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.

The role of perivitelline space abnormalities of oocytes in the developmental potential of embryos

OBJECTIVE

In assisted reproductive technology (ART), high embryo quality is closely related to high-quality oocytes. Cytoplasmic maturation and extracytoplasmic maturation are the most important components in determining oocyte quality. One of the most important components of extracytoplasmic maturation is perivitelline abnormalities. The aim of this study is to determine the effect of perivitelline abnormalities on the development of high-quality embryos.

MATERIAL AND METHODS

The study material consisted of 217 of 1154 oocytes from 98 intracytoplasmic sperm injection (ICSI) cycles undertaken due to male factor infertility. Only cycles with long gonadotropin-releasing hormone analogs combined with recombinant Follicle-stimulating hormone (rec-FSH) were included in study. We compared 105 metaphase-II oocytes that had dominantly perivitelline space abnormalities (large perivitelline space with or without granules) with 112 normal metaphase-II oocytes, based on the embryo grade determined by Alpha Scientists in Reproductive Medicine and the European Society of Human Reproduction and Embryology (ESHRE) Special Interest Group of Embryology. Normal metaphase-II oocytes were characterized by a round, clear zona pellucida; a small perivitelline space containing a single unfragmented first polar body; and a pale, moderately granular cytoplasm with no inclusions.

RESULTS

The development rates of Grade I, II, and III embryos were 68.5%, 23.8%, and 7.7%, respectively, in the 105 oocytes with perivitelline abnormalities. The development rates of Grade I, II, and III embryos were 82.1%, 17.9%, and 0%, respectively, in the 112 morphologically normal oocytes. When compared with normal oocytes, Grade I (68.5% vs. 82.1%, p value; 0.019) and Grade III (7.7% vs. 0%, p value; 0.003) embryo development rates were significantly lower in oocytes that had perivitelline abnormalities.

CONCLUSION

It is important to analyze oocyte quality using multiple parameters, including the perivitelline space. Perivitelline space abnormalities might negatively affect embryo development in male factor-infertile couples that are stimulated with rec-FSH. Therefore, when choosing embryos for transfer, we must take into consideration the historical oocyte data.