Pre-implantation genetic testing in ART: who will benefit and what is the evidence?

Transcriptome study of receptive endometrium in overweight and obese women shows important expression differences in immune response and inflammatory pathways in women who do not conceive

Obesity and being overweight are growing worldwide health problems that also affect women of reproductive age. They impair women’s fertility and are associated with lower IVF success rates. The mechanism by which increased body weight disrupts fertility has not yet been established. One possibility is that it affects the process of embryo implantation on the endometrial level. The purpose of our study was to determine the differences in enriched biological pathways in the endometrium of overweight and obese women undergoing IVF procedures. For this purpose, 14 patients (5 pregnant, 9 non-pregnant) were included in the study. Endometrial samples were obtained during the window of implantation and RNA sequencing was performed. There were no differences in general patient’s and IVF cycle characteristics between pregnant and non-pregnant women. In the endometrial samples of women who did not conceive, pathways related to the immune response, inflammation, and reactive oxygen species production were over-expressed. Our findings show that the reason for implantation failure in overweight and obese women could lie in the excessive immune and inflammatory response at the endometrial level.

Pregnancy outcomes following in vitro fertilization frozen embryo transfer (IVF-FET) with or without preimplantation genetic testing for aneuploidy (PGT-A) in women with recurrent pregnancy loss (RPL): a SART-CORS study

STUDY QUESTION

Can preimplantation genetic testing for aneuploidy (PGT-A) improve the live birth rate in patients with recurrent pregnancy loss (RPL)?

SUMMARY ANSWER

PGT-A use was associated with improved live birth rates in couples with recurrent pregnancy loss undergoing frozen embryo transfer (IVF-FET).

WHAT IS KNOWN ALREADY

Euploid embryo transfer is thought to optimize outcomes in some couples with infertility. There is insufficient evidence, however, supporting this approach to management of recurrent pregnancy loss.

STUDY DESIGN, SIZE, DURATION

This study included data collected by the Society of Assisted Reproductive Technologies Clinical Outcomes Reporting System (SART-CORS) for IVF-FET cycles between years 2010 through 2016. A total of 12 631 FET cycles in 10 060 couples were included in this analysis designed to assess the utility of PGT-A in couples with RPL undergoing FET, including 4287 cycles in couples with tubal disease who formed a control group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The experimental group included couples with RPL (strictly defined as a history of 3 or more pregnancy losses) undergoing FET with or without PGT-A. The primary outcome was live birth rate. Secondary outcomes included rates of clinical pregnancy, spontaneous abortion, and biochemical pregnancy loss. Differences were analyzed using generalized estimating equations logistic regression models to account for multiple cycles per patient. Covariates included in the model were age, gravidity, geographic region, race/ethnicity, smoking history, and indication for assisted reproductive technologies. Analyses were stratified for age groups as defined by SART: <35 years, 35-37 years, 38-40 years, 41-42 years, and >42 years.

MAIN RESULTS AND THE ROLE OF CHANCE

In women with a diagnosis of RPL, the adjusted odds ratio (OR) comparing IVF-FET with PGT-A versus without PGT-A for live birth outcome was 1.31 (95% CI: 1.12, 1.52) for age <35 years, 1.45 (95% CI: 1.21, 1.75) for ages 35-37 years, 1.89 (95% CI: 1.56, 2.29) for ages 38-40, 2.62 (95% CI: 1.94-3.53) for ages 41-42, and 3.80 (95% CI: 2.52, 5.72) for ages >42 years. For clinical pregnancy, the OR was 1.26 (95% CI: 1.08, 1.48) for age <35 years, 1.37 (95% CI: 1.14, 1.64) for ages 35-37 years, 1.68 (95% CI: 1.40, 2.03) for ages 38-40 years, 2.19 (95% CI: 1.65, 2.90) for ages 41-42, and 2.31 (95% CI: 1.60, 3.32) for ages >42 years. Finally, for spontaneous abortion, the OR was 0.95 (95% CI: 0.74, 1.21) for age <35 years, 0.85 (95% CI: 0.65, 1.11) for ages 35-37 years, 0.81 (95% CI: 0.60, 1.08) for ages 38-40, 0.86 (95% CI: 0.58, 1.27) for ages 41-42, and 0.58 (95% CI: 0.32, 1.07) for ages >42 years.

LIMITATIONS, REASONS FOR CAUTION

The retrospective collection of data including only women with recurrent pregnancy loss undergoing FET presents a limitation of this study, and results may not be generalizable to all couples with recurrent pregnancy loss. Also, data regarding evaluation and treatment for RPL for the included women is unavailable.

WIDER IMPLICATIONS OF THE FINDINGS

This is the largest study to date assessing the utility of PGT-A in women with RPL. PGT-A was associated with improvement in live birth and clinical pregnancy in women with RPL, with the largest difference noted in the group of women with age greater than 42 years. Couples with RPL warrant counseling on all management options to reduce subsequent miscarriage, which may include IVF with PGT-A for euploid embryo selection.

STUDY FUNDING/COMPETING INTEREST(S)

There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Global transcriptomic changes occur in uterine fluid-derived extracellular vesicles during the endometrial window for embryo implantation

STUDY QUESTION

Are uterine fluid-derived extracellular vesicles (UF-EVs) a 'liquid biopsy' reservoir of biomarkers for real-time monitoring of endometrial status?

SUMMARY ANSWER

The transcriptomic cargo of UF-EVs reflects the RNA profile of the endometrial tissue as well as changes between the non-receptive and the receptive phase, possibly supporting its use for a novel endometrial receptivity test.

WHAT IS KNOWN ALREADY

EVs have been previously isolated from uterine fluid, where they likely contribute to the embryo-endometrium crosstalk during implantation. Based on a meta-analysis of studies on endometrial tissue implantation-associated genes and the human exosomes database, 28 of the 57 transcripts considered as receptivity markers refer to proteins present in human exosomes. However, the specific transcriptomic content of receptive phase UF-EVs has yet to be defined.

STUDY DESIGN, SIZE, DURATION

Two experimental series were set up. First, we simultaneously sequenced RNA species derived from paired UF-EVs and endometrial tissue samples collected from physiologically cycling women. Second, we analyzed RNA species of UF-EVs collected during the non-receptive (LH + 2) and receptive (LH + 7) phase of proven fertile women and from the receptive (LH + 7) phase of a population of women undergoing ART and transfer of euploid blastocysts.

PARTICIPANTS/MATERIALS, SETTING, METHODS

For paired UF-endometrial tissue sampling, endometrial tissue biopsies were obtained with the use of a Pipelle immediately after UF collection performed by lavage of the endometrial cavity. Overall, n = 87 UF samples were collected and fresh-processed for EV isolation and total RNA extraction, while western blotting was used to confirm the expression of EV protein markers of the isolated vesicles. Physical characterization of UF-EVs was performed by Nanoparticle Tracking Analysis. To define the transcriptomic cargo of UF-EV samples, RNA-seq libraries were successfully prepared from n = 83 UF-EVs samples and analyzed by RNA-seq analysis. Differential gene expression (DGE) analysis was used to compare RNA-seq results between different groups of samples. Functional enrichment analysis was performed by gene set enrichment analysis with g:Profiler. Pre-ranked gene set enrichment analysis (GSEA) with WebGestalt was used to compare RNA-seq results with the gene-set evaluated in a commercially available endometrial receptivity array.

MAIN RESULTS AND THE ROLE OF CHANCE

A highly significant correlation was found between transcriptional profiles of endometrial biopsies and pairwise UF-EV samples (Pearson's r = 0.70 P < 0.0001; Spearman's ρ = 0.65 P < 0.0001). In UF-EVs from fertile controls, 942 gene transcripts were more abundant and 1305 transcripts less abundant in the LH + 7 receptive versus the LH + 2 non-receptive phase. GSEA performed to evaluate concordance in transcriptional profile between the n = 238 genes included in the commercially available endometrial receptivity array and the LH + 7 versus LH + 2 UF-EV comparison demonstrated an extremely significant and consistent enrichment, with a normalized enrichment score (NES)=9.38 (P < 0.001) for transcripts up-regulated in LH + 7 in the commercial array and enriched in LH + 7 UF-EVs, and a NES = -5.40 (P < 0.001) for transcripts down-regulated in LH + 7 in the commercial array and depleted in LH + 7 UF-EVs. When analyzing LH + 7 UF-EVs of patients with successful versus failed implantation after transfer of one euploid blastocyst in the following cycle, we found 97 genes whose transcript levels were increased and 64 genes whose transcript levels were decreased in the group of women who achieved a pregnancy. GSEA performed to evaluate concordance in transcriptional profile between the commercially available endometrial receptivity array genes and the comparison of LH + 7 UF-EVs of women with successful versus failed implantation, demonstrated a significant enrichment with a NES = 2.14 (P = 0.001) for transcripts up-regulated in the commercial array in the receptive phase and enriched in UF-EVs of women who conceived, and a not significant NES = -1.18 (P = 0.3) for transcripts down-regulated in the commercial array and depleted in UF-EVs. In terms of physical features, UF-EVs showed a homogeneity among the different groups analyzed except for a slight but significant difference in EV size, being smaller in women with a successful implantation compared to patients who failed to conceive after euploid blastocyst transfer (mean diameter ± SD 205.5± 22.97 nm vs 221.5 ± 20.57 nm, respectively, P = 0.014).

LARGE SCALE DATA

Transcriptomic data were deposited in NCBI Gene Expression Omnibus (GEO) and can be retrieved using GEO series accession number: GSE158958.

LIMITATIONS, REASONS FOR CAUTION

Separation of RNA species associated with EV membranes might have been incomplete, and membrane-bound RNA species-rather than the internal RNA content of EVs-might have contributed to our RNA-seq results. Also, we cannot definitely distinguish the relative contribution of exosomes, microvesicles and apoptotic bodies to our findings. When considering patients undergoing ART, we did not collect UFs in the same cycle of the euploid embryo transfer but in the one immediately preceding. We considered this approach as the most appropriate in relation to the novel, explorative nature of our study. Based on our results, a validation of UF-EV RNA-seq analyses in the same cycle in which embryo transfer is performed could be hypothesized.

WIDER IMPLICATIONS OF THE FINDINGS

On the largest sample size of human EVs ever analyzed with RNA-seq, this study establishes a gene signature to use for less-invasive endometrial receptivity tests. This report is indeed the first to show that the transcriptome of UF-EVs correlates with the endometrial tissue transcriptome, that RNA signatures in UF-EVs change with endometrial status, and that UF-EVs could serve as a reservoir for potential less-invasive collection of receptivity markers. This article thus represents a step forward in the design of less-invasive approaches for real-time monitoring of endometrial status, necessary for advancing the field of reproductive medicine.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by a competitive grant from European Society of Human Reproduction and Embryology (ESHRE Research Grant 2016-1). The authors have no financial or non-financial competing interests to disclose.

TRIAL REGISTRATION NUMBER

NA.

How fixed versus variable gonadotropin dose during controlled ovarian stimulation could influence the management of infertility patients undergoing IVF treatment: a national Delphi consensus

AIM

Define how and when fixed starting gonadotropin doses can be used in current clinical ART practices in Italy.

METHODS

A Delphi conference consisting of three rounds was performed in order to define the ideal clinical conditions in which fixed-gonadotropin-dose during COS should be applied. During the conference, 19 statements about the current ART practice were provided to a panel of twenty-nine national experts. Median score was 5 (IQ:4-6) in all Delphi rounds.

RESULTS

Eleven statements (57.9%) were classified as shareable with high-degree of convergence, 2 (10.5%) as shareable with low convergence and 6 (31.6%) as un-shareable with high convergence. The panel reached high consensus regarding some statements: (i) fixed FSH-dose in normoresponders and poor-responder, (ii) importance of predicting ovarian response before COS, considering multiple markers to select the right stimulation protocol for each patient, (iii) importance of therapy simplification and standardization to improve efficiency during COS. Moreover, a low-convergence was reached about use of GnRH antagonist as first treatment line and drug storage at room temperature. However from these findings, the debate remains open regarding some other statements: (a) usefulness of Bologna-criteria to define poor-responders; (b) efficacy to change always stimulation protocol after a failure IVF; (c) utility of AMH-dosed with standardized automatic mode to define normo-responder patients; (d) usefulness to modify the dosage of 12.5 IU/die during COS to improve stimulation effectiveness.

CONCLUSION

Controlled ovarian stimulation remains a challenging clinical step in Assisted Reproductive Technique, especially in some specific patient groups for which no clinical consensus is available. This study is the first attempt to describe the shared clinical opinion regarding the fixed versus variable gonadotropin dose in the real IVF practice.

National survey on the opinions of French specialists in assisted reproductive technologies about social issues impacting the future revision of the French Bioethics laws

INTRODUCTION

France is known for its conservative and unique position in assisted reproductive technologies (ARTs). At the eve of the future revision of French Bioethics laws, we decided to conduct a national survey to examine the opinions of French specialists in ARTs about social issues.

MATERIAL AND METHODS

Descriptive study conducted in May 2017 in a university teaching hospital using an anonymous online questionnaire on current issues in ARTs. The questionnaire was sent by email to 650 French ARTs specialists, both clinicians and embryologists.

RESULTS

After 3 reminders, 408 responses were collected resulting in a participation rate of 62.7% (408/650). Concerning pre-implantation genetic testing, 80% of the physicians were in favor of expanding the indications, which in France are presently limited to incurable genetic diseases. Authorizing elective Fertility Preservation was supported by 93.4% of the specialists, but without social coverage for 86.3% of them. Concerning gamete donation, 77.4% of the French ARTs specialists were in favor of giving a financial compensation to donors, 92% promoted preserving their anonymity and 80.9% were against a directed donation. ARTs for single heterosexual women were supported by 63.4% of the French specialists and by 72.5% for lesbian couples. The legalization of surrogacy was requested by 55.2%.

DISCUSSION

Pending the revision of the French Bioethics laws, this survey provides an overview of the opinion of the specialists in ARTs on expanding ARTs for various social indications.Because of the evolution of social values, a more liberal and inclusive ART program is desired by the majority of ART specialists in France.

Non-invasive mitochondrial DNA quantification on Day 3 predicts blastocyst development: a prospective, blinded, multi-centric study

In ART, embryo quality evaluation is routinely based on morphological criteria. We previously demonstrated that the mitochondrial DNA (mtDNA)/genomic DNA (gDNA) ratio in culture medium was significantly associated with embryo quality and viability potential. The purpose of this prospective, blinded, multi-centric study was to validate the use of mtDNA/gDNA ratio in Day 3 spent medium as a predictor of human embryo developmental competence. The mtDNA/gDNA ratio was assessed in Day 3 culture media (n=484) of embryos from 143 patients by quantitative PCR. A mixed effect logistic regression model was applied. We found that mtDNA/gDNA ratio in Day 3 culture medium combined with embryo morphology improves the prediction upon blastulation compared to morphology alone (P < 0.0001), independent of patient and cycle characteristics. With regard to routine use in clinics, we evaluated the ability of the novel, combined grading score to improve selection of developmentally competent embryos of a single cohort. Including embryos from 44 patients, the sensibility and specificity of the scoring system based on Day 3 morphological stage were 92% and 13%, respectively. Integration with the culture medium mtDNA/gDNA ratio increased the performance of the method (sensibility: 95%; specificity: 65%). The results of this study suggest the possibility of carrying out a non-invasive evaluation of embryonic mtDNA content through the culture medium. When combined with embryo morphology, it has the potential to help embryologists rank embryos and choose which embryo(s) has the greater development potential, and thus should be transferred on Day 3, among sibling embryos with the same morphological grade.

Pre-implantation genetic diagnosis in an Iranian family with a novel mutation in MUT gene

Background

Methylmalonic acidemia (MMA), which is an autosomal recessive metabolic disorder, is caused by mutations in methylmalonyl-CoA mutase (MUT) gene. As a result, the conversion of methylmalonyl-CoA to succinyl-CoA is impaired in this disorder, leading to a wide range of clinical manifestations varying from no signs or symptoms to severe lethargy and metabolic crisis in newborn infants. Since identification of novel mutations in MUT gene can help discover the exact pathogenesis of MMA and also use these disease-causing mutations in prenatal diagnosis, this study was conducted to uncover the possible mutations in an Iranian couple with a deceased offspring clinically diagnosed as having organic acidemia. Moreover, to prevent the occurrence of the mutation in the next pregnancy, we took the advantage of pre-implantation genetic diagnosis (PGD), which resulted in a successful pregnancy.

Case presentation

The affected individual was a 15-month-old boy who passed away due to aspiration pneumonia. The child presented at the age of 3 months with lethargy, protracted vomiting, hypotonia, and decreased level of consciousness. To find the mutated gene, Next Generation Sequencing (NGS) was performed as carrier testing for the parents and the results revealed a novel (private) heterozygous missense mutation in MUT gene (c.1055A > G, p.Q352R). After performing PGD on three blastomeres, one was identified as being homozygous wild-type that was followed by successful pregnancy.

Conclusions

Our study identified a novel, deleterious, heterozygous missense mutation in MUT gene in a couple and helps to consider the genetic counselling and prenatal diagnosis more seriously for this family with clinical phenotypes of organic acidemia.

Transient Sperm Starvation Improves the Outcome of Assisted Reproductive Technologies

To become fertile, mammalian sperm must undergo a series of biochemical and physiological changes known as capacitation. These changes involve crosstalk between metabolic and signaling pathways and can be recapitulated in vitro. In this work, sperm were incubated in the absence of exogenous nutrients (starved) until they were no longer able to move. Once immotile, energy substrates were added back to the media and sperm motility was rescued. Following rescue, a significantly higher percentage of starved sperm attained hyperactivated motility and displayed increased ability to fertilize in vitro when compared with sperm persistently incubated in standard capacitation media. Remarkably, the effects of this treatment continue beyond fertilization as starved and rescued sperm promoted higher rates of embryo development, and once transferred to pseudo-pregnant females, blastocysts derived from treated sperm produced significantly more pups. In addition, the starvation and rescue protocol increased fertilization and embryo development rates in sperm from a severely sub-fertile mouse model, and when combined with temporal increase in Ca²⁺ ion levels, this methodology significantly improved fertilization and embryo development rates in sperm of sterile CatSper1 KO mice model. Intracytoplasmic sperm injection (ICSI) does not work in the agriculturally relevant bovine system. Here, we show that transient nutrient starvation of bovine sperm significantly enhanced ICSI success in this species. These data reveal that the conditions under which sperm are treated impact post-fertilization development and suggest that this “starvation and rescue method” can be used to improve assisted reproductive technologies (ARTs) in other mammalian species, including humans.

State of the art and emerging drug therapies for female infertility

At present, infertility is a key-issue. When applicable, in vitro fertilization (IVF) has become the standard approach to treat this condition but a thorough investigation and, whenever possible, the individual diagnosis of the underlying causes of infertility are required. For many female causes, indeed, efficient medical therapies are available to achieve a fast solution of the problem. This review is based on the relevant literature indexed in PubMed and SCOPUS and is focused on the most recent clinical literature on the treatment of women (and couples) affected from infertility. The reduction in IVF treatment burden and risks are now considered pivotal to set 'patient-friendly' therapies and represent crucial issues for both patients and physicians. To this end, the researchers are now focusing their attention on old drugs with new indications and new compounds with more appropriate functions, to improve the compliance of the women and reduce the burden of infertility, a condition that is becoming an important issue in the modern world, also for the Public Health System.

Stem cells and reproduction

Reproductive biotechnology has developed rapidly and is now able to overcome many birth difficulties due to infertility or the transmission of genetic diseases. Here we introduce the next generation of assisted reproductive technologies (ART), such as mitochondrial replacement technique (MRT) or genetic correction in eggs with micromanipulation. Further, we suggest that the transmission of genetic information from somatic cells to subsequent generations without gametes should be useful for people who suffer from infertility or genetic diseases. Pluripotent stem cells (PSCs) can be converted into germ cells such as sperm or oocytes in the laboratory. Notably, germ cells derived from nuclear transfer embryonic stem cells (NT-ESCs) or induced pluripotent stem cells (iPSCs) inherit the full parental genome. The most important issue in this technique is the generation of a haploid chromosome from diploid somatic cells. We hereby examine current science and limitations underpinning these important developments and provide recommendations for moving forward.

Endometrial scratching for infertile women undergoing a first embryo transfer: a systematic review and meta-analysis of published and unpublished data from randomized controlled trials

OBJECTIVE

To investigate endometrial scratch injury (ESI) as an intervention to improve IVF outcome in women undergoing a first ET.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertile women undergoing a first fresh/frozen embryo transfer.

INTERVENTION(S)

We included published and unpublished data from randomized controlled trials in which the intervention group received ESI and controls received placebo or no intervention. Pooled results were expressed as relative risk (RR) with 95% confidence interval (CI). The review protocol was registered in PROSPERO to start the data extraction (CRD42018087786).

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy/live birth rate (OPR/LBR), clinical pregnancy rate (CPR), multiple pregnancy rate (MPR), miscarriage rate (MR), and ectopic pregnancy rate (EPR).

RESULT(S)

Seven studies were included (1,354 participants). We found a nonsignificant difference between groups in terms of OPR/LBR, CPR, MR, MPR, and EPR. Subgroup analysis found that ESI on the day of oocyte retrieval (achieved by a Novak curette) reduced OPR/LBR (RR 0.31, 95% CI 0.14-0.69) and CPR (RR 0.36, 95% CI 0.18-0.71), whereas ESI during the cycle preceding ET (performed through soft devices) had no effect on OPR/LBR and CPR. No difference in the impact of ESI was observed between fresh and frozen embryo transfer.

CONCLUSION(S)

Current evidence does not support performing ESI with the purpose of improving the success of a first ET attempt.

Single best euploid versus single best unknown-ploidy blastocyst frozen embryo transfers: a randomized controlled trial

PURPOSE

This paper aims to investigate the efficacy of IVF with preimplantation genetic testing for aneuploidy (PGT-A), using only best-scoring blastocysts from young (≤ 35 years) infertile patients undergoing single blastocyst frozen embryo transfers (FET).

METHOD

In this randomized controlled trial (RCT) registered 29 March 2017, 302 infertile patient-couples eligible to participate underwent autologous ICSI blastocyst freeze-all cycles. Two-hundred and twenty patient-couples satisfied the inclusion criteria (i.e., female age ≤ 35 years, two-day 5 ≥ 2BB blastocysts) and were randomized to either the PGT-A (PGT-A group, n = 109) selection arm or morphology score (morphology group, n = 111) selection arm. In both arms, the highest ranking (by morphological score) blastocysts were selected for FET.

RESULTS

Of the 109 best-scoring blastocysts that underwent PGT-A, 80 were predicted to be euploid (73.4%) and were transferred in FET (euploid subgroup). There was no statistical difference in LB rate between the euploid subgroup and morphology group (56.3% vs 58.6%, odds ratio 0.91 (95% CI 0.51-1.63), p = 0.750). In a multiple logistic regression, the transfer of euploid blastocysts was not found to be a significant predictor of LB when adjusting for female age, infertility duration, antral follicle count, and blastocyst quality, with the independent odds expressed as 0.91 (95% CI 0.50-1.66, p = 0.760).

CONCLUSION

In young (≤ 35 years) infertile patients with at least two ≥ 2BB blastocysts, PGT-A blastocyst selection does not result in an enhanced LB rate, with the evidence suggesting that the effectivity of PGT-A may be limited by the effectivity of TE biopsy.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03095053.

Euploid embryos selected by an automated time-lapse system have superior SET outcomes than selected solely by conventional morphology assessment

PURPOSE

We investigated if automated TLI selection may be a valuable strategy to identify those euploid embryos with the best chances of success.

METHODS

This is a unicentric and retrospective study involving 244 patients undergoing preimplantational genetic screening (PGS) cycles with autologous oocytes or oocyte donation (OD) with single euploid embryo transferred. We examined euploid embryos selected for transfer based on morphology evaluation alone (PGS-only; control group) or by assessment using an automated TLI system (Eeva™; PGS-TLI group).

RESULTS

In both, autologous oocytes and OD patients, significantly better implantation and clinical and ongoing pregnancy rates were obtained in the PGS-TLI group when euploid embryos with high implantation potential as predicted by the automated TLI System (Eeva™) were transferred compared with the PGS-only group. This improvement was also observed when only transfers of good morphological quality embryos were compared. TLI categories showed significant differences on blastocyst formation and euploidy rate.

CONCLUSIONS

Automated TLI combined with PGS is a useful prognostic tool to identify euploid embryos with the highest potential for implantation and pregnancy. Further, these results provide evidence that a healthy pregnancy does not only depend upon normal chromosomal status.

Contraction behaviour reduces embryo competence in high-quality euploid blastocysts

PURPOSE

The aim of the study is to investigate how blastocyst contraction behaviour affects the reproductive competence in high-quality euploid embryos.

METHODS

Eight hundred ninety-six high-quality blastocysts derived from 190 patients (mean age 38.05 (SD = 2.9) years) who underwent preimplantation genetic testing for aneuploidies (PGT-A) from January 2016 to October 2017 were included in this study. PGT-A results were reported as euploid or aneuploid. Aneuploid embryos were sub-classified into three categories: monosomy, trisomy and complex aneuploid. Retrospective studies of time-lapse monitoring (TLM) of those embryos were analysed and reproductive outcome of transferred embryos was collected.

RESULTS

A total of 234/896 were euploid (26.1%) whilst 662/896 (73.9%) blastocysts were proven to be aneuploid from which 116 (17.6%) presented monosomies, 136 (20.5%) trisomies and 410 (61.9%) were complex aneuploid. The most frequent chromosomal complements were trisomies affecting chromosome 21 and monosomies involving chromosomes 16 and 22. Data analysis showed a statistical difference in the number of contractions being reported greater in aneuploid when compared to euploid embryos (0.6 vs 1.57; p < 0.001). Analysis of the aneuploid embryos showed that monosomies present less number of contractions when compared to embryos affected with trisomies or complex aneuploidies (1.23 vs 1.53 and 1.40; p < 0.05). No difference was observed when comparing the latter two groups. Euploid embryos presenting at least one contraction resulted in lower implantation and clinical pregnancy rates when compared to blastocysts that do not display this event (47.6 vs 78.5% and 40.0 vs 59.0% respectively).

CONCLUSIONS

Most aneuploid blastocysts diagnosed by PGT-A have complex aneuploidies, showing that aneuploid embryos can develop after genomic activation and reaching high morphological scores. It becomes clear that embryo contraction, despite being a physiological feature during blastulation, is conditioned by the ploidy status of the embryo. Furthermore, the presence of contractions may compromise implantation rates.

Assisted hatching and live births in first-cycle frozen embryo transfers

OBJECTIVE

To assess the effect of assisted hatching (AH) on live-birth rates in a retrospective cohort of patients undergoing first-cycle, autologous frozen embryo transfer (FET).

DESIGN

Longitudinal cohort using cycles reported to the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System between 2004 and 2013.

SETTING

Not applicable.

PATIENT(S)

Women who underwent first-cycle, autologous FET with (n = 70,738) and without (n = 80,795) AH reported from 2004 to 2013.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Live births.

RESULT(S)

Propensity matching was used to account for confounding covariates, and a logistic regression model was constructed to identify the predictors of live-birth rates in relationship to AH. In all first-cycle FETs, there was a slight but statistically significant decrease in the live-birth rate with AH compared with no AH (34.2% vs. 35.4%). In older patients and in the years 2012-2013 AH was associated with decreased live births. Live-birth rates and the number of AH cycles performed before FET vary by the geographic location of clinics.

CONCLUSION(S)

Assisted hatching slightly decreases the live-birth rate in first-cycle, autologous FET. Its use should be carefully considered, especially in patients 38 years old and older. Prospective, clinical studies are needed to improve our knowledge of the impact of AH.

Predictive value of spindle retardance in embryo implantation rate

PURPOSE

We evaluated the relationship between meiotic spindle characteristics and in vitro fertilization cycle outcome.

METHODS

Five hundred sixty-nine oocytes from 86 in vitro fertilization cycles were analyzed for fertilization and subsequent implantation rates. Oocytes were assessed for maturation status. The oocytes and embryos were cultured in sequential and nonsequential media (G Series, Vitrolife, Sweden) and incubated in 6% CO₂, 5% O₂ at 37 °C. Two hours following oocyte decumulation (38-39 h post-hCG/GnRH administration) and prior to microinjection, the structure of the meiotic spindle was assessed using the Oosight Imaging System (CRI, UK).

RESULTS

Four hundred fifty-six oocytes (80.5%) had a visible meiotic spindle, 82 (14.7%) had no meiotic spindle, and 31 (5.5%) were in telophase I. Oocytes exhibiting a meiotic spindle had a significantly higher fertilization rate and a lower rate of abnormal fertilization. Implantation data were obtained for 195 of the embryos transferred. The implantation rate for embryos derived from oocytes with a meiotic spindle was 32.9%, while in embryos originating from oocytes without a meiotic spindle and oocytes in telophase, this value dropped significantly (8.8 and 0%, respectively). To determine the correlation between retardance values and implantation rate for each oocyte, we established four groups, finding a range of retardance values with significantly higher implantation rates (27.5, 21, 29.3, and 53.8%, respectively).

CONCLUSION

Meiotic spindle imaging may be a valuable tool for prediction of oocyte quality, and retardance values of meiotic spindles, together with classical morphological classification, can be useful to select embryos with a higher implantation potential.