Preimplantation genetic screening (PGS) with Comparative genomic hybridization (CGH) following day 3 single cell blastomere biopsy markedly improves IVF outcomes while lowering multiple pregnancies and miscarriages

The first clinical validation of whole-genome screening on standard trophectoderm biopsies of preimplantation embryos

Objective

To validate the performance of our laboratory-developed whole-genome screening assay within clinical preimplantation genetic testing environments.

Design

Perform a laboratory-developed whole-genome assay on both cell lines and trophectoderm biopsies, subsequently employing the next-generation sequencing procedure to reach a sequencing depth of 30X. Adhere to the Genome Analysis Toolkit best practices for accuracy, sensitivity, specificity, and precision calculations by comparing samples with references. Our assay was then applied to cell lines and biopsies harboring known pathogenic variants, aiming to ascertain these changes solely from the next-generation sequencing data, independent of parental genome information.

Settings

Clinical laboratory.

Patients

Coriell cell lines and research embryos with known chromosomal or genetic variants. Research trophectoderm biopsies from a couple that are heterozygous carriers for distinct variants in the same autosomal recessive gene (HOGA1).

Intervention

Not applicable.

Main Outcome Measures

Accuracy, sensitivity, specificity, and precision were assessed by comparing the samples to their references. For samples with known variants, we calculated our sensitivity to detecting established variants. For the research embryos, noncarrier, carrier, and compound heterozygous states of inherited HOGA1 variants were distinguished independently of parental samples.

Results

Amplification of DNA from cell lines and embryos yielded success rates exceeding 99.9% and 98.2%, respectively, although maintaining an accuracy of >99.9% for aneuploidy assessment. The accuracy (99.99%), specificity (99.99%), sensitivity (98.0%), and precision (98.1%) of amplified genome in the bottle (reference NA12878) and embryo biopsies were comparable to results on genomic DNA, including mitochondrial heteroplasmy. Using our assay, we achieved >99.99% sensitivity when examining samples with known chromosomal and genetic variants. This encompassed pathogenic CFTR, BRCA1, and other variants, along with uniparental isodisomies and microdeletions such as DiGeorge syndrome. Our research study identified noncarrier, carrier, and compound heterozygous states within trophectoderm biopsies while simultaneously screening for 1,300 other severe monogenic diseases.

Conclusion

To our knowledge, this is the first clinical validation of whole-genome embryo screening. In this study, we demonstrated high accuracy for aneuploidy calls (>99.9%) and genetic variants (99.99%), even in the absence of parental genomes. This assay demonstrates advancements in genomic screening and an extended scope for testing capabilities in the realm of preimplantation genetic testing.

Risk of embryo aneuploidy is affected by the increase in sperm DNA damage in recurrent implantation failure patients under ICSI-CGH array cycles

This study investigates the relationship between sperm DNA damage in recurrent implantation failure (RIF) patients treated with comparative genomic hybridisation array-intracytoplasmic sperm injection (CGH array-ICSI) cycles and embryo aneuploidy screening. Forty-two RIF couples were selected. Sperm DFI was measured using TUNEL by flow cytometry. Two groups were defined as follows: (i) sperm with high DFI (> 20%); and (ii) low DFI (< 20%). Semen parameters, total antioxidant capacity (TAC), and malondialdehyde formation (MDA) were also measured in both groups. Following oocyte retrieval and ICSI procedure, blastomere biopsy was performed at the 4th day of development and evaluated with CGH-array. The high DFI group had a significant (p = 0.04) increase in the number of aneuploid embryos compared to the low one. According to Poisson regression results, the risk of aneuploidy embryos in the high DFI group was 55% higher than the low DFI group (RR = 1.55; 95% CI = 1.358-1.772). Moreover, chromosomal analysis showed an elevation of aneuploidy in chromosomes number 16 and 20 in the high DFI group compared to the low DFI group (p < 0.05). The high DFI in RIF patients may significantly affect the risk of aneuploidy embryos. Therefore, embryo selection by CGH-array should be considered for couples with high levels of sperm DNA fragmentation.

Preimplantation genetic testing for aneuploidy in severe male factor infertility: protocol for a multicenter randomised controlled trial

INTRODUCTION

Conventional intracytoplasmic sperm injection (ICSI) is a widely used treatment for couples with severe male infertility. However, there are controversies regarding the selection and the damage to gametes during the ICSI procedure. Although preimplantation genetic testing for aneuploidies (PGT-A) can give genetic information about embryos for transfer and improve fertility rate, and it is widely used in women with recurrent spontaneous abortion or advanced age, PGT-A is not only more expensive but also has unclear effectiveness with respect to the improvement of fertility rate among couples with severe male infertility. High-quality, well-powered randomised clinical trials (RCTs) comparing ICSI+PGT-A and ICSI are lacking.

METHODS AND ANALYSIS

This is a protocol for a multicenter, open-label RCT in four reproductive medical centers qualified for PGT technique in China. We will study couples with severe male infertility scheduled for their fertility treatment. After the blastocyst culture, eligible participants are randomised to the ICSI+PGT-A group or the conventional ICSI group in a 1:1 ratio. Other assisted reproductive procedures are similar and parallel between the two groups. The primary outcome will be live birth rate and cumulative live-birth rate . Secondary outcomes will be embryo implantation rate, biochemical pregnancy rate, clinical pregnancy rate, spontaneous abortion rate, ongoing pregnancy rate, preterm birth rate, fetal chromosomal abnormality rate, birth defect rate and treatment complications. To demonstrate or refute a difference between the two groups, we plan to include 188 participants in each group; taking consideration of 20% of dropout, the total target sample size is 450.

ETHICS AND DISSEMINATION

Ethical approval was obtained from International Peace Maternity and Child Health Hospital of Shanghai Jiao Tong University Medical Science Research Ethics Committee (GKLW2016-16). Informed consent will be obtained from each participant. The findings will be disseminated to the public through conference presentations and publication in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT02941965.

Contribution of senescence in human endometrial stromal cells during proliferative phase to embryo receptivity†

Successful assisted reproductive technology pregnancy depends on the viability of embryos and endometrial receptivity. However, the literature has neglected effects of the endometrial environment during the proliferative phase on implantation success or failure. Human endometrial stromal cells (hESCs) were isolated from endometrial tissues sampled at oocyte retrieval during the proliferative phase from women undergoing infertility treatment. Primary hESC cultures were used to investigate the relationship between stemness and senescence induction in this population and embryo receptivity. Patients were classified as receptive or non-receptive based on their pregnancy diagnosis after embryo transfer. Biomarkers of cellular senescence and somatic stem cells were compared between each sample. hESCs from non-receptive patients exhibited significantly higher (P < 0.01) proportions of senescent cells, mRNA expressions of CDKN2A and CDKN1A transcripts (P < 0.01), and expressions of genes encoding the senescence-associated secretory phenotype (P < 0.05). hESCs from receptive patients had significantly higher (P < 0.01) mRNA expressions of ABCG2 and ALDH1A1 transcripts. Our findings suggest that stemness is inversely associated with senescence induction in hESCs and, by extension, that implantation failure in infertility treatment may be attributable to a combination of senescence promotion and disruption of this maintenance function in this population during the proliferative phase of the menstrual cycle. This is a promising step towards potentially improving the embryo receptivity of endometrium. The specific mechanism by which implantation failure is prefigured by a loss of stemness among endometrial stem cells, and cellular senescence induction among hESCs, should be elucidated in detail in the future.

Different Strategies of Preimplantation Genetic Testing for Aneuploidies in Women of Advanced Maternal Age: A Systematic Review and Meta-Analysis

Background: Preimplantation genetic testing for aneuploidies (PGT-A) is widely used in women of advanced maternal age (AMA). However, the effectiveness remains controversial. Method: We conducted a comprehensive literature review comparing outcomes of IVF with or without PGT-A in women of AMA in PubMed, Embase, and the Cochrane Central Register of Controlled Trials in January 2021. All included trials met the criteria that constituted a randomized controlled trial for PGT-A involving women of AMA (≥35 years). Reviews, conference abstracts, and observational studies were excluded. The primary outcome was the live birth rate in included random control trials (RCTs). Results: Nine randomized controlled trials met our inclusion criteria. For techniques of genetic analysis, three trials (270 events) performed with comprehensive chromosomal screening showed that the live birth rate was significantly higher in the women randomized to IVF/ICSI with PGT-A (RR = 1.30, 95% CI 1.03–1.65), which was not observed in six trials used with FISH as well as all nine trials. For different stages of embryo biopsy, only the subgroup of blastocyst biopsy showed a higher live birth rate in women with PGT-A (RR = 1.36, 95% CI 1.04–1.79). Conclusion: The application of comprehensive chromosome screening showed a beneficial effect of PGT-A in women of AMA compared with FISH. Moreover, blastocyst biopsy seemed to be associated with a better outcome than polar body biopsy and cleavage-stage biopsy.

Preimplantation Genetic Testing for Aneuploidy: Current Perspectives

Despite improvements in assisted reproduction techniques (ARTs), live birth rates remain suboptimal, particularly in women with advanced maternal age (AMA). The leading cause of poor reproductive outcomes demonstrated in women with AMA, as well as women with recurrent miscarriage and repetitive implantation failure, is thought to be due to high rates of embryonic aneuploidy. Preimplantation genetic testing for aneuploidies (PGT-A) aims to select an euploid embryo for transfer and therefore improve ART outcomes. Early PGT-A studies using fluorescent in situ hybridization on mainly cleavage-stage biopsies failed to show improved delivery rates and, in certain cases, were even found to be harmful. However, the development of comprehensive chromosome screening, as well as improvements in culture media and vitrification techniques, has resulted in an emerging body of evidence in favor of PGT-A, demonstrating higher implantation, pregnancy, and live birth rates. While there are concerns regarding the potential harm of invasive biopsy and the cost implications of PGT-A, the introduction of noninvasive techniques and the development of new high-throughput methods which lower costs are tackling these issues. This review aims to assess the evidence for PGT-A, address possible concerns regarding PGT-A, and also explore the future direction of this technology.

ChromInst: A single cell sequencing technique to accomplish pre-implantation comprehensive chromosomal screening overnight

Next Generation Sequencing (NGS) is a powerful tool getting into the field of clinical examination. Its preliminary application in pre-implantation comprehensive chromosomal screening (PCCS) of assisted reproduction (test-tube baby) has shown encouraging outcomes that improves the success rate of in vitro fertilization. However, the conventional NGS library construction is time consuming. In addition with the whole genome amplification (WGA) procedure in prior, makes the single cell NGS assay hardly be accomplished within an adequately short turnover time in supporting fresh embryo implantation. In this work, we established a concise single cell sequencing protocol, ChromInst, in which the single cell WGA and NGS library construction were integrated into a two-step PCR procedure of ~ 2.5hours reaction time. We then validated the feasibility of ChromInst for overnight PCCS assay by examining 14 voluntary donated embryo biopsy samples in a single sequencing run of Miseq with merely 13M reads production. The good compatibility of ChromInst with the restriction of Illumina sequencing technique along with the good library yield uniformity resulted superior data usage efficiency and reads distribution evenness that ensures precisely distinguish of 6 normal embryos from 8 abnormal one with variable chromosomal aneuploidy. The superior succinctness and effectiveness of this protocol permits its utilization in other time limited single cell NGS applications.

A Rapid NGS-Based Preimplantation Genetic Testing for Chromosomal Abnormalities in Day-3 Blastomere Biopsy Allows Embryo Transfer Within the Same Treatment Cycle

Nowadays, most of the preimplantation genetic testing (PGT) is performed with a strategy of comprehensive chromosome screening and trophectoderm biopsy. Nevertheless, patients with ovarian insufficiency may not have competent blastocysts. In the present study, we aimed to establish the value of multiple annealing and looping-based amplification cycle (MALBAC)-based next-generation sequencing (NGS) for PGT in day-3 embryos. A total of 94.3% (1168/1239) of embryos yielded informative results, and the overall embryo euploid rate was 21.9% (256/1168). Overall, 225 embryos were transferred in 169 cycles with a clinical pregnancy rate of 49.1% (83/169). The live birth and implantation rates were 47.3% (80/169) and 44.4% (100/225), respectively. Double embryos transfer showed higher clinical pregnancy and live birth rates compared with single embryo transfer, but the implantation rates were similar (44.2% vs. 44.6%, P > 0.05). The euploid rate for reciprocal translocations (16.1%) was significantly lower than that for Robertsonian translocations (28.0%, P < 0.01) and inversions (28.0%, P < 0.01). However, higher percentages of embryos with de novo abnormalities were observed with Robertsonian translocations (23.3%, P < 0.01) and inversions (30.5%, P < 0.01) than with reciprocal translocations (11.6%). We demonstrated that NGS for PGT on day-3 embryos is an effective clinical application, particularly for patients with a diminished ovarian reserve and limited embryos.

Comparison of PGS2.0 versus conventional embryo morphology evaluation for patients with recurrent pregnancy loss: a study protocol for a multicentre randomised trial

INTRODUCTION

Pregnancy loss (PL) is an adverse life event, and there is no proven effective treatment for recurrent PL (RPL). Preimplantation genetic screening (PGS) can be performed to reduce the risks of PL; however, there is still no solid scientific evidence that PGS improves outcomes for couples experiencing RPL. Comprehensive chromosome screening (PGS2.0) has become a routine practice in in vitro fertilisation (IVF) clinics. Previous studies based on PGS1.0 with a focus on RPL couples where the female is of advanced maternal age have reported contradictory results. Hence, a multicentre randomised trial is needed to provide evidence for the clinical benefits of PGS2.0 treatment for RPL couples.

METHODS AND ANALYSIS

Overall, 268 RPL couples undergoing IVF cycles will be enrolled. Couples will be randomised according to a unique grouping number generated by a random digital software into (1) PGS2.0 group and (2) non-PGS (conventional embryo morphology evaluation) group. This study aims to investigate whether the live birth rate (LBR) per initiated cycle after PGS2.0 is superior to the LBR per initiated cycle after conventional embryo evaluation (non-PGS group). Live birth will be defined as a live baby born after a gestation period of >28 weeks, with a birth weight of more than 1000 g. A multivariate logistic regression model will be used to adjust for confounding factors.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Ethics Committee of Obstetrics and Gynecology Hospital, Fudan University and the participating hospitals. Written informed consent will be obtained from each couple before any study procedure is performed. Data from this study will be stored in the Research Electronic Data Capture. The results of this trial will be presented and published via peer-reviewed publications and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NCT03214185; Pre-results.

Clinical application of embryo aneuploidy testing by next-generation sequencing

We review here the evolution in the field of embryo aneuploidy testing over the last 20 years, from the analysis of a subset of chromosomes by fluorescence in situ hybridisation to the transition toward a more comprehensive analysis of all 24 chromosomes. This current comprehensive aneuploidy testing most commonly employs next-generation sequencing (NGS). We present our experience in over 130 000 embryo biopsies using this technology. The incidence of aneuploidy was lower in trophectoderm biopsies compared to cleavage-stage biopsies. We also confirmed by NGS that embryo aneuploidy rates increased with increasing maternal age, mostly attributable to an increase in complex aneuploid embryos. In contrast, the number of MII oocytes retrieved or the use of oocyte vitrification did not affect aneuploidy rates. Similarly, neither maternal age, oocyte number, nor oocyte vitrification affected the incidence of mosaicism. Analysis of clinical outcomes, indications, and potential benefits of embryo aneuploidy testing revealed advanced maternal age as the most favored group, with some evidence of improved delivery rate per transfer as well as decreased miscarriage rates and time to pregnancy. Other indications are: recurrent miscarriage, repetitive implantation failure, severe male factor, previous trisomic pregnancy, and good prognosis patients mainly undergoing single embryo transfer, with the latter indication used to reduce the occurrence of multiple pregnancies without compromising cycle outcome. In conclusion, NGS has become the most appropriate technology for aneuploidy testing in trophectoderm biopsies, with accurate results, high throughput, and cost efficiency. This technology can be also applied to the analysis of the embryonic cell free DNA released to the culture media at blastocyst stage. This is a promising approach towards a non-invasive preimplantation genetic testing of aneuploidy.

The demise of preimplantation genetic testing for aneuploidy (PGT-A) in Hungary and its effect on patient care

Preimplantation genetic testing for aneuploidy (PGT-A) is a suitable technique to identify euploid embryos, which have the highest potential to implant, thus increase the chance of a healthy live birth. The main indications of PGT-A are advanced maternal age, repeated implantation failure, repeated miscarriages and severe male infertility. Several studies have already proven that testing embryos for genetic abnormalities in the above cases results in higher implantation rate and reduced number of pregnancy loss. In spite of these - due to a legislative change in Hungary in 2015 - PGT-A was reclassified as an experimental procedure and its use became banned throughout the country. For this reason, after 4 years of successful practice, Hungarian patients were not able to participate in IVF procedure combined with PGT-A anymore. In this retrospective analysis, efficacy of PGT-A-based embryo selection was evaluated and was compared to the conventional morphology-based selection (MBS) in patients with advanced maternal age, between 2013 and 2017 at our private fertility clinic. PGT-A was performed with array comparative genomic hybridization. We found that implantation rate was significantly higher (43.62% vs. 27.88%; p = 0.0208) and miscarriage rate was significantly lower (17.07% vs. 37.93%; p = 0.0492) in the PGT-A group compared to the MBS group from 2013 to 2015. These outcomes were achieved with a significantly lower number of transferred embryos in the PGT-A group (1.25 vs. 1.58; p = 0.0003). In 2016-2017, the number of transferred embryos were significantly reduced in the MBS group as well (1.14 vs. 1.58; p < 0.0001). However, outcomes of the IVF treatments did not change significantly compared to the previous two years (2013-2015). Our results imply that PGT-A-based embryo selection is more efficient than morphology-based selection in patients with advanced maternal age. Therefore, prohibition of the use of PGT-A had significant consequences on the efficiency and safety of IVF treatment in the country.

Pregnancy rates after pre-implantation genetic screening for aneuploidy are only superior when trophectoderm biopsy is performed on hatching embryos

PURPOSE

In vitro fertilization with trophectoderm embryo biopsy and pre-implantation genetic screening with comprehensive chromosomal screening (PGS-CCS) for aneuploidy is becoming increasingly more popular. Embryos are cryopreserved and implanted in a subsequent frozen thawed embryo transfer cycle (FET). No studies have investigated differences in pregnancy outcomes by timing of trophectoderm biopsy relative to stages of blastocyst development.

METHODS

Retrospective study of all patients (n = 363) at a single IVF center between January 1, 2013 and December 31, 2016 undergoing single embryo transfer with PGS-CCS where embryos were cryopreserved with subsequent FET. Embryo expansion and grading was assessed both at the time of biopsy and transfer. Pregnancy rates were analyzed by embryo expansion and embryo grading.

RESULTS

Implantation, clinical pregnancy, and live birth rates improved significantly with increased embryo expansion at the time of embryo biopsy (P < 0.001). Pregnancy loss decreased with increases in embryo expansion prior to biopsy (P < 0.001). Superior live birth rates with PGS-CCS were seen when embryos were hatching at the time of biopsy (p < 0.001). For fresh and frozen embryo transfers without PGS-CCS, embryo expansion did not affect pregnancy outcomes.

CONCLUSIONS

PGS-CCS significantly increases implantation and live birth rates only if embryos are hatching at the time of biopsy. The embryo biopsy itself on a non-hatching embryo significantly damages the embryo in ways which are not reflected in future embryo expansion. IVF labs should wait until embryos hatch before performing trophectoderm biopsy.

Pregnancy and child developmental outcomes after preimplantation genetic screening: a meta-analytic and systematic review

BACKGROUND

In in vitro fertilization (IVF) treatment, preimplantation genetic diagnosis/screening (PGD/S) attempts to detect chromosomal abnormalities in embryos before implantation. Using the meta-analytic and qualitative review approaches, this study aims to evaluate the effect of PGD/S on clinical pregnancy, live births, and childhood outcomes.

METHODS

We conducted a literature search using 1) PubMed and other search engines, and 2) an ancestry search by tracking references cited in prior work. After screening the studies, we extracted information pertinent to the meta-analysis. We calculated the effect sizes for clinical pregnancy and live birth rates, and performed a moderation analysis by maternal age, type of genetic screening, and timing of the biopsy. For childhood outcomes, we conducted a systematic review of studies reporting the anthropometric, psychomotor, cognitive, behavioral, and family functioning of PGD/S children.

RESULTS

We included 26 studies for clinical pregnancy and live births, and 18 studies for childhood outcomes. Results indicated that women who underwent comprehensive chromosome screening-based PGD/S had significantly higher clinical pregnancy rates (rr 1.207, 95% CI 1.017-1.431) and live birth rates (rr 1.362, 95% CI 1.057-1.755) than those whose IVF treatment did not include PGD/S. Early childhood outcomes of PGD/S children did not differ from those of non-PGD/S children.

CONCLUSIONS

Comprehensive chromosome screening-based PGD/S can improve clinical pregnancy and live birth rates without adversely affecting functioning in childhood at least up to age 9. Results are discussed in the context of bioethical, financial, legal, and psychological issues surrounding PGD/S.

Chromosomal analysis in IVF: just how useful is it?

Designed to minimize chances of genetically abnormal embryos, preimplantation genetic diagnosis (PGD) involves in vitro fertilization (IVF), embryo biopsy, diagnosis and selective embryo transfer. Preimplantation genetic testing for aneuploidy (PGT-A) aims to avoid miscarriage and live born trisomic offspring and to improve IVF success. Diagnostic approaches include fluorescence in situ hybridization (FISH) and more contemporary comprehensive chromosome screening (CCS) including array comparative genomic hybridization (aCGH), quantitative polymerase chain reaction (PCR), next-generation sequencing (NGS) and karyomapping. NGS has an improved dynamic range, and karyomapping can detect chromosomal and monogenic disorders simultaneously. Mosaicism (commonplace in human embryos) can arise by several mechanisms; those arising initially meiotically (but with a subsequent post-zygotic 'trisomy rescue' event) usually lead to adverse outcomes, whereas the extent to which mosaics that are initially chromosomally normal (but then arise purely post-zygotically) can lead to unaffected live births is uncertain. Polar body (PB) biopsy is the least common sampling method, having drawbacks including cost and inability to detect any paternal contribution. Historically, cleavage-stage (blastomere) biopsy has been the most popular; however, higher abnormality levels, mosaicism and potential for embryo damage have led to it being superseded by blastocyst (trophectoderm - TE) biopsy, which provides more cells for analysis. Improved biopsy, diagnosis and freeze-all strategies collectively have the potential to revolutionize PGT-A, and there is increasing evidence of their combined efficacy. Nonetheless, PGT-A continues to attract criticism, prompting questions of when we consider the evidence base sufficient to justify routine PGT-A? Basic biological research is essential to address unanswered questions concerning the chromosome complement of human embryos, and we thus entreat companies, governments and charities to fund more. This will benefit both IVF patients and prospective parents at risk of aneuploid offspring following natural conception. The aim of this review is to appraise the 'state of the art' in terms of PGT-A, including the controversial areas, and to suggest a practical 'way forward' in terms of future diagnosis and applied research.

The interval transfer of a frozen-thawed embryo is more successful than a fresh embryo transfer for women undergoing IVF with recurrent implantation failure after cleavage stage embryo biopsy

BACKGROUND

Recurrent implantation failure (RIF) is repeated unsuccessful embryo transfers (ETs).

AIMS

To identify predictive embryonic markers of implantation in RIF, following pre-implantation genetic screening (PGS) of cleavage stage embryos, after accounting for male and female factors.

MATERIALS AND METHODS

Retrospective analysis of RIF patients undergoing PGS after correction of modifiable causes.

RESULTS

Eighty-four patients underwent 140 in vitro ferilisation cycles. Forty-one cycles were excluded: 12 (no embryo for transfer), four (double ETs) and 25 (no biopsy). Sixty-three patients underwent 99 single euploid ETs (48 fresh, 51 frozen) resulting in 11 biochemical pregnancies, 36 clinical pregnancies (CP), and six miscarriages and 30 live births (LB). Frozen ET was more successful than fresh; respective live birth rate (LBR) and clinical pregnancy rate (CPR), 39.2% versus 20.8%, (P = 0.02), 45.1% versus 27.1% (P = 0.04). LBR and CPR were lower when 5-6 blastomeres were present at embryo biopsy, compared to embryos with ≥7 blastomeres: 15.4% versus 32.6% (P = 0.185) and 15.4% versus 39.5% (P = 0.074) respectively. Serum β human chorionic gonadotropin (βhCG) concentration was greater when a more developed embryo was biopsied (r = 0.448, P = 0.017 and r = 0.476, P = 0.118, fresh and frozen transfers, respectively). Embryo morphokinetic analysis demonstrated faster development to blastocyst stage when more cells were present at biopsy: mean 103.3, 102.2 and 96.0 h for biopsy at the 5-6, 7-8 or ≥9 cell stage respectively (P = 0.040 for difference between 7-8 cells vs ≥9).

CONCLUSIONS

After cleavage stage biopsy, frozen ET was more successful than fresh ET. Chance of conception and serum βhCG concentration correlated with number of cells present at time of biopsy.

Noninvasive chromosome screening of human embryos by genome sequencing of embryo culture medium for in vitro fertilization

Preimplantation genetic screening (PGS) is widely used to select in vitro-fertilized embryos free of chromosomal abnormalities and to improve the clinical outcome of in vitro fertilization (IVF). A disadvantage of PGS is that it requires biopsy of the preimplantation human embryo, which can limit the clinical applicability of PGS due to the invasiveness and complexity of the process. Here, we present and validate a noninvasive chromosome screening (NICS) method based on sequencing the genomic DNA secreted into the culture medium from the human blastocyst. By using multiple annealing and looping-based amplification cycles (MALBAC) for whole-genome amplification (WGA), we performed next-generation sequencing (NGS) on the spent culture medium used to culture human blastocysts (n = 42) and obtained the ploidy information of all 24 chromosomes. We validated these results by comparing each with their corresponding whole donated embryo and obtained a high correlation for identification of chromosomal abnormalities (sensitivity, 0.882, and specificity, 0.840). With this validated NICS method, we performed chromosome screening on IVF embryos from seven couples with balanced translocation, azoospermia, or recurrent pregnancy loss. Six of them achieved successful clinical pregnancies, and five have already achieved healthy live births thus far. The NICS method avoids the need for embryo biopsy and therefore substantially increases the safety of its use. The method has the potential of much wider chromosome screening applicability in clinical IVF, due to its high accuracy and noninvasiveness.

Novel embryo selection techniques to increase embryo implantation in IVF attempts

PURPOSE

The final success of an IVF attempt depends on several steps and decisions taken during the ovarian stimulation, the oocyte retrieval, the embryo culture and the embryo transfer. The final selection of the embryos most likely to implant is the final step in this process and the responsibility of the lab. Apart from strict morphologic criteria that historically have been used in embryo selection, additional information on genetic, metabolomic and morphokinetic characteristics of the embryo is recently combined to morphology to select the embryo most likely to produce a pregnancy. In this manuscript, we review the most recent information on the current methods used for embryo selection presenting the predictive capability of each one.

METHODS

A literature search was performed on Pubmed, Medline and Cochrane Database of Systematic Reviews for published studies using appropriate key words and phrases with no limits placed on time.

RESULTS

It seems that the combination of morphologic criteria in conjunction to embryo kinetics as documented by time-lapse technology provides the most reliable information on embryo quality. Blastocyst biopsy with subsequent comprehensive chromosome analysis allows the selection of the euploid embryos with the higher implantation potential.

CONCLUSION

Embryo time-lapse imaging and blastocyst biopsy combined to comprehensive chromosome analysis are the most promising technologies to increase pregnancy rates and reduce the possibility of multiple pregnancies. However, further studies will demonstrate the capability of routinely using these technologies to significantly improve IVF outcomes.

Recent advances in preimplantation genetic diagnosis and screening

Preimplantation genetic diagnosis/screening (PGD/PGS) aims to help couples lower the risks of transmitting genetic defects to their offspring, implantation failure, and/or miscarriage during in vitro fertilization (IVF) cycles. However, it is still being debated with regard to the practicality and diagnostic accuracy of PGD/PGS due to the concern of invasive biopsy and the potential mosaicism of embryos. Recently, several non-invasive and high-throughput assays have been developed to help overcome the challenges encountered in the conventional invasive biopsy and low-throughput analysis in PGD/PGS. In this mini-review, we will summarize the recent progresses of these new methods for PGD/PGS and discuss their potential applications in IVF clinics.

A pilot proof-of-principle study to compare fresh and vitrified cycle preimplantation genetic screening by chromosome microarray and next generation sequencing

BACKGROUND

Single embryo transfer (SET) has been utilized as a strategy to reduce the chance of multifetal gestations in in vitro fertilization (IVF) but lower pregnancy rate remains a concern. Recent studies showed that favorable outcome regarding SET can be achieved by selecting embryos with "more normal" genetic components. We explored the use of rapid array comparative genomic hybridization (aCGH) to select blastocysts for fresh SET and compared with the protocols adopting vitrified (ultrarapidly frozen) embryo transfer cycle. Validation of the rapid protocol of aCGH and comparison of the result with the regular protocol of aCGH and next generation sequencing (NGS) are also performed.

RESULTS

First-time IVF patients with normal karyotype (n = 21) were enrolled for elective fresh SET cycle (n = 8; designated as fresh SET group) or vitrified embryo transfer cycle (n = 13; designated as vitrified ET group) coupling with comprehensive chromosomal screening by a 9-h rapid aCGH from Day 5 trophectoderm (TE) biopsy. In fresh SET group, 86 blastocysts (10.8 blastocysts/patient) were biopsied and analyzed. Aneuploidy was detected in 53.5 % (46/86) of the biopsied blastocysts. All patients had a single embryo transferred on the following day. The clinical pregnancy rate was 87.5 % (7/8) and the ongoing pregnancy rate was 62.5 % (5/8). In vitrified ET group, 58 blastocysts (4.5 blastocysts/patient) were biopsied and 56 blastocysts were analyzed. Aneuploidy was detected in 39.3 % (22/56) of biopsies. The patients accepted for SET or double embryos transfer (DET) in non-stimulated cycles. The clinical pregnancy rate and the ongoing pregnancy rate was 76.9 % (10/13) and 53.8 % (7/13) respectively. Spontaneous abortions occurred in both of the two patient groups. In the series of fresh SET group, no twin pregnancy was noted and at least one healthy baby had been born at gestational age (GA) 37(+6) weeks when submission. The results of PGS by rapid aCGH, regular aCGH and NGS were comparable in most occasions.

CONCLUSION

This study evaluates the use of rapid aCGH to select blastocysts for fresh SET and demonstrates its feasibility in a real clinical IVF program. A successful livebirth is achieved and the favorable outcome is superior to the protocol adopting vitrified ET cycle in our own setting. Additional studies are needed to verify this pilot data and validate its application in large randomized trials.

Discrepant diagnosis rate of array comparative genomic hybridization in thawed euploid blastocysts

PURPOSE

Preimplantation genetic screening (PGS) and diagnosis (PGD) with euploid embryo transfer is associated with improved implantation and live birth rates as compared to routine in vitro fertilization. However, misdiagnosis of the embryo is a potential risk. The purpose of this study was to investigate the clinical discrepant diagnosis rate associated with transfer of trophectoderm-biopsied blastocysts deemed to be euploid via array comparative genomic hybridization (aCGH).

METHODS

This is a retrospective cohort study including cycles utilizing PGS or PGD with trophectoderm biopsy, aCGH, and euploid embryo transfer at a large university-based fertility center with known birth outcomes from November 2010 through July 2014 (n = 520).

RESULTS

There were 520 embryo transfers of 579 euploid embryos as designated by aCGH. Five discrepant diagnoses were identified. Error rate per embryo transfer cycle was 1.0 %, 0.9 % per embryo transferred, and 1.5 % per pregnancy with a sac. The live birth (LB) error rate was 0.7 % (both sex chromosome errors), and the spontaneous abortion (SAB) error rate was 17.6 % (3/17 products of conception tested, but could range from 3/42 to 7/42). No single gene disorders were mistakenly selected for in any known cases. 

CONCLUSIONS

Although aCGH has been shown to be a highly sensitive method of comprehensive chromosome screening, several possible sources of error still exist. While the overall error rate is low, these findings have implications for counseling couples that are contemplating PGS and PGD with aCGH.

Omics in Reproductive Medicine: Application of Novel Technologies to Improve the IVF Success Rate

Treatment for many infertile couples often consists of in vitro fertilization (IVF) but an estimated 70% of IVF cycles fail to produce a live birth. In an attempt to improve the live birth rate, the vast majority of IVF cycles performed in the United States involve the transfer of multiple embryos, a practice that increases the risk of multiple gestation pregnancy. This is a concern because multiple gestation pregnancies are associated with an increased incidence of maternal and fetal complications and significant cost associated with the care of preterm infants. As the ideal outcome of each IVF cycle is the birth of a single healthy baby, significant effort has focused on identifying embryos with the greatest developmental potential. To date, selection of euploid embryos using comprehensive chromosome screening (CCS) is the most promising approach while metabolomic and proteomic assessment of spent culture medium have the potential to noninvasively assess embryo viability. Endometrial gene expression profiling may help determine the optimal time to perform embryo transfer. While CCS has been implemented in some clinics, further development and optimization will be required before analysis of spent culture medium and endometrial gene expression profiling make the transition to clinical use. This review will describe efforts to identify embryos with the greatest potential to result in a healthy, live birth, with a particular emphasis on detection of embryo aneuploidy and metabolic profiling of spent embryo culture medium. Assessment of endometrial receptivity to identify the optimal time to perform embryo transfer will also be discussed.

The IMSI Procedure Improves Laboratory and Clinical Outcomes Without Compromising the Aneuploidy Rate When Compared to the Classical ICSI Procedure

PURPOSE

The intracytoplasmic morphologically selected sperm injection (IMSI) procedure has been associated with better laboratory and clinical outcomes in assisted reproduction technologies. Less information is available regarding the relationship between embryo aneuploidy rate and the IMSI procedure. The aim of this study is to compare the clinical outcomes and chromosomal status of IMSI-derived embryos with those obtained from intracytoplasmic sperm injection (ICSI) in order to establish a clearer view of the benefits of IMSI in infertile patients.

METHODS

We retrospectively analyzed a total of 11 cycles of IMSI and 20 cycles of ICSI with preimplantation genetic diagnosis. The fertilization rate, cleavage rate, embryo quality, blastocyst development, aneuploidy rate, pregnancy rate, implantation rate, and miscarriage rate were compared between the groups.

RESULTS

Similar rates of fertilization (70% and 73%), cleavage (98% and 100%), and aneuploidy (76.9% and 70.9%) were observed in the IMSI and ICSI groups, respectively. The IMSI group had significantly more good quality embryos at day 3 (95% vs 73%), higher blastocyst development rates (33% vs 19%), and greater number of hatching blastocysts (43% vs 28%), cycles with at least one blastocyst at day 5 (55% vs 35%), and blastocysts with good trophoectoderm morphology (21% vs 6%) compared with the ICSI group (P < 0.001). Significantly higher implantation rates were observed in the IMSI group compared with the ICSI group (57% vs 27%; P < 0.05). Pregnancy and miscarriage rates were similar in both groups (80% vs 50% and 0% vs 33%, respectively).

CONCLUSION

The IMSI procedure significantly improves the embryo quality/development by increasing the implantation rates without affecting the chromosomal status of embryos. There is a tendency for the IMSI procedure to enhance the pregnancy rates and lower the miscarriage rates when compared with ICSI.

Can Comprehensive Chromosome Screening Technology Improve IVF/ICSI Outcomes? A Meta-Analysis

Objective

To examine whether comprehensive chromosome screening (CCS) for preimplantation genetic screening (PGS) has an effect on improving in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes compared to traditional morphological methods.

Methods

A literature search was conducted in PubMed, EMBASE, CNKI and ClinicalTrials.gov up to May 2015. Two reviewers independently evaluated titles and abstracts, extracted data and assessed quality. We included studies that compared the IVF/ICSI outcomes of CCS-based embryo selection with those of the traditional morphological method. Relative risk (RR) values with corresponding 95% confidence intervals (CIs) were calculated in RevMan 5.3, and subgroup analysis and Begg’s test were used to assess heterogeneity and potential publication bias, respectively.

Results

Four RCTs and seven cohort studies were included. A meta-analysis of the outcomes showed that compared to morphological criteria, euploid embryos identified by CCS were more likely to be successfully implanted (RCT RR 1.32, 95% CI 1.18–1.47; cohort study RR 1.74, 95% CI 1.35–2.24). CCS-based PGS was also related to an increased clinical pregnancy rate (RCT RR 1.26, 95% CI 0.83–1.93; cohort study RR 1.48, 95% CI 1.20–1.83), an increased ongoing pregnancy rate (RCT RR 1.31, 95% CI 0.64–2.66; cohort study RR 1.61, 95% CI 1.30–2.00), and an increased live birth rate (RCT RR 1.26, 95% CI 1.05–1.50; cohort study RR 1.35, 95% CI 0.85–2.13) as well as a decreased miscarriage rate (RCT RR 0.53, 95% CI 0.24–1.15; cohort study RR 0.31, 95% CI 0.21–0.46) and a decreased multiple pregnancy rate (RCT RR 0.02, 95% CI 0.00–0.26; cohort study RR 0.19, 95% CI 0.07–0.51). The results of the subgroup analysis also showed a significantly increased implantation rate in the CCS group.

Conclusions

The effectiveness of CCS-based PGS is comparable to that of traditional morphological methods, with better outcomes for women receiving IVF/ICSI technology. The transfer of both trophectoderm-biopsied and blastomere-biopsied CCS-euploid embryos can improve the implantation rate.

Technical Update: Preimplantation Genetic Diagnosis and Screening

OBJECTIVE

To update and review the techniques and indications of preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS).

OPTIONS

Discussion about the genetic and technical aspects of preimplantation reproductive techniques, particularly those using new cytogenetic technologies and embryo-stage biopsy.

OUTCOMES

Clinical outcomes of reproductive techniques following the use of PGD and PGS are included. This update does not discuss in detail the adverse outcomes that have been recorded in association with assisted reproductive technologies.

EVIDENCE

Published literature was retrieved through searches of The Cochrane Library and Medline in April 2014 using appropriate controlled vocabulary (aneuploidy, blastocyst/physiology, genetic diseases, preimplantation diagnosis/methods, fertilization in vitro) and key words (e.g., preimplantation genetic diagnosis, preimplantation genetic screening, comprehensive chromosome screening, aCGH, SNP microarray, qPCR, and embryo selection). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies published from 1990 to April 2014. There were no language restrictions. Searches were updated on a regular basis and incorporated in the update to January 2015. Additional publications were identified from the bibliographies of retrieved articles. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. (Table 1) BENEFITS, HARMS, AND COSTS: This update will educate readers about new preimplantation genetic concepts, directions, and technologies. The major harms and costs identified are those of assisted reproductive technologies.

SUMMARY

Preimplantation genetic diagnosis is an alternative to prenatal diagnosis for the detection of genetic disorders in couples at risk of transmitting a genetic condition to their offspring. Preimplantation genetic screening is being proposed to improve the effectiveness of in vitro fertilization by screening for embryonic aneuploidy. Though FISH-based PGS showed adverse effects on IVF success, emerging evidence from new studies using comprehensive chromosome screening technology appears promising. Recommendations 1. Before preimplantation genetic diagnosis is performed, genetic counselling must be provided by a certified genetic counsellor to ensure that patients fully understand the risk of having an affected child, the impact of the disease on an affected child, and the benefits and limitations of all available options for preimplantation and prenatal diagnosis. (III-A) 2. Couples should be informed that preimplantation genetic diagnosis can reduce the risk of conceiving a child with a genetic abnormality carried by one or both parents if that abnormality can be identified with tests performed on a single cell or on multiple trophectoderm cells. (II-2B) 3. Invasive prenatal or postnatal testing to confirm the results of preimplantation genetic diagnosis is encouraged because the methods used for preimplantation genetic diagnosis have technical limitations that include the possibility of a false result. (II-2B) 4. Trophectoderm biopsy has no measurable impact on embryo development, as opposed to blastomere biopsy. Therefore, whenever possible, trophectoderm biopsy should be the method of choice in embryo biopsy and should be performed by experienced hands. (I-B) 5. Preimplantation genetic diagnosis of single-gene disorders should ideally be performed with multiplex polymerase chain reaction coupled with trophectoderm biopsy whenever available. (II-2B) 6. The use of comprehensive chromosome screening technology coupled with trophectoderm biopsy in preimplantation genetic diagnosis in couples carrying chromosomal translocations is recommended because it is associated with favourable clinical outcomes. (II-2B) 7. Before preimplantation genetic screening is performed, thorough education and counselling must be provided by a certified genetic counsellor to ensure that patients fully understand the limitations of the technique, the risk of error, and the ongoing debate on whether preimplantation genetic screening is necessary to improve live birth rates with in vitro fertilization. (III-A) 8. Preimplantation genetic screening using fluorescence in situ hybridization technology on day-3 embryo biopsy is associated with decreased live birth rates and therefore should not be performed with in vitro fertilization. (I-E) 9. Preimplantation genetic screening using comprehensive chromosome screening technology on blastocyst biopsy, increases implantation rates and improves embryo selection in IVF cycles in patients with a good prognosis. (I-B).

Diagnosis of human preimplantation embryo viability

BACKGROUND

Transfer of more than a single embryo in an IVF cycle comes with the finite possibility of a multiple gestation. Even a twin pregnancy confers significant risk to both mother and babies. The move to single-embryo transfer for all patients will be greatly facilitated by the ability to quantify embryo viability. Developments in time-lapse incubation systems have provided new insights into the developmental kinetics of the human preimplantation embryo. Advances in molecular methods of chromosomal analysis have created platforms for highly effective screening of biopsied embryos, while noninvasive analysis of embryo physiology reveals more about the embryo than can be determined by morphology alone.

METHODS

Recent developments in time-lapse microscopy, molecular karyotyping and in proteomics and metabolomics have been assessed and presented here in a descriptive review.

RESULTS AND CONCLUSIONS

New algorithms are being created for embryo selection based on their developmental kinetics in culture, and the impact of factors such as patient etiology and treatment are being clarified. Potential links between morphokinetic data and embryo karyotype are being elucidated. The introduction of new molecular methods of determining embryo chromosomal complement is proving to be accurate and reproducible, with the future trending toward CGH arrays or next generation sequencing as a rapid and reliable means of analysis, that should be suitable for each IVF clinic to adopt. A relationship between embryo metabolism and viability is established and is now being considered together with morphokinetic data to create more robust algorithms for embryo selection. Microfluidic devices have the capacity and potential to be used in human IVF clinics for the routine diagnosis of embryo biomarkers.

Impact of blastocyst biopsy and comprehensive chromosome screening technology on preimplantation genetic screening: a systematic review of randomized controlled trials

Embryonic aneuploidy is highly prevalent in IVF cycles and contributes to decreased implantation rates, IVF cycle failure and early pregnancy loss. Preimplantation genetic screening (PGS) selects the most competent (euploid) embryos for transfer, and has been proposed to improve IVF outcomes. Use of PGS with fluorescence-in-situ hybridization technology after day 3 embryo biopsy (PGS-v1) significantly lowers live birth rates and is not recommended for use. Comprehensive chromosome screening technology, which assesses the whole chromosome complement, can be achieved using different genetic platforms. Whether PGS using comprehensive chromosome screening after blastocyst biopsy (PGS-v2) improves IVF outcomes remains to be determined. A systematic review of randomized controlled trials was conducted on PGS-v2. Three trials met full inclusion criteria, comparing PGS-v2 and routine IVF care. PGS-v2 is associated with higher clinical implantation rates, and higher ongoing pregnancy rates when the same number of embryos is transferred in both PGS and control groups. Additionally, PGS-v2 improves embryo selection in eSET practice, maintaining the same ongoing pregnancy rates between PGS and control groups, while sharply decreasing multiple pregnancy rates. These results stem from good-prognosis patients undergoing IVF. Whether these findings can be extrapolated to poor-prognosis patients with decreased ovarian reserve remains to be determined.

The clinical effectiveness of preimplantation genetic diagnosis for aneuploidy in all 24 chromosomes (PGD-A): systematic review

STUDY QUESTION

Is preimplantation genetic diagnosis for aneuploidy (PGD-A) with analysis of all chromosomes during assisted reproductive technology (ART) clinically and cost effective?

SUMMARY ANSWER

The majority of published studies comparing a strategy of PGD-A with morphologically assessed embryos have reported a higher implantation rate per embryo using PGD-A, but insufficient data has been presented to evaluate the clinical and cost-effectiveness of PGD-A in the clinical setting.

WHAT IS KNOWN ALREADY

Aneuploidy is a leading cause of implantation failure, miscarriage and congenital abnormalities in humans, and a significant cause of ART failure. Preclinical evidence of PGD-A indicates that the selection and transfer of euploid embryos during ART should improve clinical outcomes.

STUDY DESIGN, SIZE AND DURATION

A systematic review of the literature was performed for full text English language articles using MEDLINE, EMBASE, SCOPUS, Cochrane Library databases, NHS Economic Evaluation Database and EconLit. The Downs and Black scoring checklist was used to assess the quality of studies. Clinical effectiveness was measured in terms of pregnancy, live birth and miscarriage rates.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Nineteen articles meeting the inclusion criteria, comprising three RCTs in young and good prognosis patients and 16 observation studies were identified. Five of the observational studies included a control group of patients where embryos were selected based on morphological criteria (matched cohort studies).

MAIN RESULTS AND ROLE OF CHANCE

Of the five studies that included a control group and reported implantation rates, four studies (including two RCTs) demonstrated improved implantation rates in the PGD-A group. Of the eight studies that included a control group, six studies (including two RCTs) reported significantly higher pregnancy rates in the PGD-A group, and in the remaining two studies, equivalent pregnancies rates were reported despite fewer embryos being transferred in the PGD-A group. The three RCTs demonstrated benefit in young and good prognosis patients in terms of clinical pregnancy rates and the use of single embryo transfer. However, studies relating to patients of advanced maternal age, recurrent miscarriage and implantation failure were restricted to matched cohort studies, limiting the ability to draw meaningful conclusions.

LIMITATIONS, REASONS FOR CAUTION

Relevant studies may have been missed and findings from RCTs currently being undertaken could not be included.

WIDER IMPLICATIONS OF THE FINDINGS

Given the uncertain role of PGD-A techniques, high-quality experimental studies using intention-to-treat analysis and cumulative live birth rates including the comparative outcomes from remaining cryopreserved embryos are needed to evaluate the overall role of PGD-A in the clinical setting. It is only in this way that the true contribution of PGD-A to ART can be understood.

[Update on preimplantation genetic diagnosis and screening]

Recent advancement in both human embryology and genomics has created a completely new situation for practical and widespread application of preimplantation genetic diagnosis and screening with a dramatic effect on assisted reproduction. The mapping of the first human genome and the advancement in sequencing technology and bioinformatics has led to the discovery of the exact genetic background of exponentially increasing number of diseases. In parallel, methods for culturing human embryos have also radically improved, enabling the late transfer, and the procedure of vitrification the safe cryopreservation. In consequence, refined genetic analyses have become available from blastocyst biopsy followed by the application of novel genomic methods. Furthermore, some studies suggest that by the selection of aneuploid embryos the pregnancy- and birth-rates can be increased. The amount and the depth of information obtainable from the embryos raise several technical and ethical questions that can be answered by further prospective randomized trials.

Current status of comprehensive chromosome screening for elective single-embryo transfer

Most in vitro fertilization (IVF) experts and infertility patients agree that the most ideal assisted reproductive technology (ART) outcome is to have a healthy, full-term singleton born. To this end, the most reliable policy is the single-embryo transfer (SET). However, unsatisfactory results in IVF may result from plenty of factors, in which aneuploidy associated with advanced maternal age is a major hurdle. Throughout the past few years, we have got a big leap in advancement of the genetic screening of embryos on aneuploidy, translocation, or mutations. This facilitates a higher success rate in IVF accompanied by the policy of elective SET (eSET). As the cost is lowering while the scale of genome characterization continues to be up over the recent years, the contemporary technologies on trophectoderm biopsy and freezing-thaw, comprehensive chromosome screening (CCS) with eSET appear to be getting more and more popular for modern IVF centers. Furthermore, evidence has showen that, by these avant-garde techniques (trophectoderm biopsy, vitrification, and CCS), older infertile women with the help of eSET may have an opportunity to increase the success of their live birth rates approaching those reported in younger infertility patients.

New tools for embryo selection: comprehensive chromosome screening by array comparative genomic hybridization

The objective of this study was to evaluate the usefulness of comprehensive chromosome screening (CCS) using array comparative genomic hybridization (aCGH). The study included 1420 CCS cycles for recurrent miscarriage (n = 203); repetitive implantation failure (n = 188); severe male factor (n = 116); previous trisomic pregnancy (n = 33); and advanced maternal age (n = 880). CCS was performed in cycles with fresh oocytes and embryos (n = 774); mixed cycles with fresh and vitrified oocytes (n = 320); mixed cycles with fresh and vitrified day-2 embryos (n = 235); and mixed cycles with fresh and vitrified day-3 embryos (n = 91). Day-3 embryo biopsy was performed and analyzed by aCGH followed by day-5 embryo transfer. Consistent implantation (range: 40.5–54.2%) and pregnancy rates per transfer (range: 46.0–62.9%) were obtained for all the indications and independently of the origin of the oocytes or embryos. However, a lower delivery rate per cycle was achieved in women aged over 40 years (18.1%) due to the higher percentage of aneuploid embryos (85.3%) and lower number of cycles with at least one euploid embryo available per transfer (40.3%). We concluded that aneuploidy is one of the major factors which affect embryo implantation.