Search

Research Question: How does first-trimester aneuploidy screening perform in pregnancies achieved through IVF with preimplantation genetic testing for aneuploidy (PGT-A) in a medical setting?, Design: This retrospective cohort study was undertaken in a single tertiary care centre between January 2013 and June 2022. In total, 20,237 women had prenatal follow-up at the study centre and were included in the study. The women were divided into three groups: singleton pregnancies conceived through the transfer of a PGT-A-screened euploid embryo (n = 510); singleton pregnancies conceived through IVF without PGT-A (n = 3291); and singleton pregnancies conceived naturally (n = 16,436)., Results: The conventional combined screening test for pregnancies conceived through IVF with PGT-A had specificity of 91%; sensitivity could not be calculated as there were no cases of fetal aneuploidy in this group. In 89.1% of pregnancies conceived through IVF with PGT-A with high risk for trisomy 21, 18 or 13, the result was related to advanced maternal age (>35 years at time of screening)., Conclusions: The current screening strategy for trisomies 21, 18 and 13 can generate unnecessary tests in pregnancies achieved through IVF with PGT-A. A new protocol is needed for these patients, with greater weight given to ultrasound markers., (Copyright © 2023 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Is partial compaction during morula formation associated with an embryo's developmental ability and implantation potential?, Design: Retrospective analysis of data from 196 preimplantation genetic testing for aneuploidy (PGT-A) cycles. Embryos starting compaction were grouped according to the inclusion or not of all the blastomeres in the forming morula (full compaction or partial compaction). The possible effect of maternal age and ovarian response on compaction was analysed. Morphokinetic characteristics, blastocyst formation rate, morphology and cytogenetic constitution of the obtained blastocysts were compared. Comparisons of reproductive outcomes after the transfer of euploid blastocysts from both groups were established. Finally, in a subset of embryos, the chromosomal constitution concordance of the abandoned cells and the corresponding blastocyst through trophectoderm biopsies was assessed., Results: A total of 430 embryos failed to include at least one cell during compaction (partial compaction group [49.3%]), whereas the 442 remaining embryos formed a fully compacted morula (full compaction group [50.7%]). Neither female age nor the number of oocytes collected affected the prevalence of partial compaction morulae. Morphokinetic parameters were altered in embryos from partial compaction morulae compared with full compaction. Although an impairment in blastocyst formation rate was observed in partial compaction morulae (57.2% versus 70.8%, P < 0.001), both chromosomal constitution (euploidy rate: partial compaction [38.4%] versus full compaction [34.2%]) and reproductive outcomes (live birth rate: partial compaction [51.9%] versus full compaction [46.2%]) of the obtained blastocysts were equivalent between groups. A high ploidy correlation of excluded cells-trophectoderm duos was observed., Conclusions: Partial compaction morulae show a reduced developmental ability compared with full compaction morulae. Resulting blastocysts from both groups, however, have similar euploidy rates and reproductive outcomes. Cell exclusion might be a consequence of a compromised embryo development regardless of the chromosomal constitution of the excluded cells., (Copyright © 2023 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Study Question: Does the diagnosis of mosaicism affect ploidy rates across different providers offering preimplantation genetic testing for aneuploidies (PGT-A)?, Summary Answer: Our analysis of 36 395 blastocyst biopsies across eight genetic testing laboratories revealed that euploidy rates were significantly higher in providers reporting low rates of mosaicism., What Is Known Already: Diagnoses consistent with chromosomal mosaicism have emerged as a third category of possible embryo ploidy outcomes following PGT-A. However, in the era of mosaicism, embryo selection has become increasingly complex. Biological, technical, analytical, and clinical complexities in interpreting such results have led to substantial variability in mosaicism rates across PGT-A providers and clinics. Critically, it remains unknown whether these differences impact the number of euploid embryos available for transfer. Ultimately, this may significantly affect clinical outcomes, with important implications for PGT-A patients., Study Design, Size, Duration: In this international, multicenter cohort study, we reviewed 36 395 consecutive PGT-A results, obtained from 10 035 patients across 11 867 treatment cycles, conducted between October 2015 and October 2021. A total of 17 IVF centers, across eight PGT-A providers, five countries and three continents participated in the study. All blastocysts were tested using trophectoderm biopsy and next-generation sequencing. Both autologous and donation cycles were assessed. Cycles using preimplantation genetic testing for structural rearrangements were excluded from the analysis., Participants/materials, Setting, Methods: The PGT-A providers were randomly categorized (A to H). Providers B, C, D, E, F, G, and H all reported mosaicism, whereas Provider A reported embryos as either euploid or aneuploid. Ploidy rates were analyzed using multilevel mixed linear regression. Analyses were adjusted for maternal age, paternal age, oocyte source, number of embryos biopsied, day of biopsy, and PGT-A provider, as appropriate. We compared associations between genetic testing providers and PGT-A outcomes, including the number of chromosomally normal (euploid) embryos determined to be suitable for transfer., Main Results and the Role of Chance: The mean maternal age (±SD) across all providers was 36.2 (±5.2). Our findings reveal a strong association between PGT-A provider and the diagnosis of euploidy and mosaicism. Amongst the seven providers that reported mosaicism, the rates varied from 3.1% to 25.0%. After adjusting for confounders, we observed a significant difference in the likelihood of diagnosing mosaicism across providers (P < 0.001), ranging from 6.5% (95% CI: 5.2-7.4%) for Provider B to 35.6% (95% CI: 32.6-38.7%) for Provider E. Notably, adjusted euploidy rates were highest for providers that reported the lowest rates of mosaicism (Provider B: euploidy, 55.7% (95% CI: 54.1-57.4%), mosaicism, 6.5% (95% CI: 5.2-7.4%); Provider H: euploidy, 44.5% (95% CI: 43.6-45.4%), mosaicism, 9.9% (95% CI: 9.2-10.6%)); and Provider D: euploidy, 43.8% (95% CI: 39.2-48.4%), mosaicism, 11.0% (95% CI: 7.5-14.5%)). Moreover, the overall chance of having at least one euploid blastocyst available for transfer was significantly higher when mosaicism was not reported, when we compared Provider A to all other providers (OR = 1.30, 95% CI: 1.13-1.50). Differences in diagnosing and interpreting mosaic results across PGT-A laboratories raise further concerns regarding the accuracy and relevance of mosaicism predictions. While we confirmed equivalent clinical outcomes following the transfer of mosaic and euploid blastocysts, we found that a significant proportion of mosaic embryos are not used for IVF treatment., Limitations, Reasons for Caution: Due to the retrospective nature of the study, associations can be ascertained, however, causality cannot be established. Certain parameters such as blastocyst grade were not available in the dataset. Furthermore, certain platform-related and clinic-specific factors may not be readily quantifiable or explicitly captured in our dataset. As such, a full elucidation of all potential confounders accounting for variability may not be possible., Wider Implications of the Findings: Our findings highlight the strong need for standardization and quality assurance in the industry. The decision not to transfer mosaic embryos may ultimately reduce the chance of success of a PGT-A cycle by limiting the pool of available embryos. Until we can be certain that mosaic diagnoses accurately reflect biological variability, reporting mosaicism warrants utmost caution. A prudent approach is imperative, as it may determine the difference between success or failure for some patients., Study Funding/competing Interest(s): This work was supported by the Torres Quevedo Grant, awarded to M.P. (PTQ2019-010494) by the Spanish State Research Agency, Ministry of Science and Innovation, Spain. M.P., L.B., A.R.L., A.L.R.d.C.L., N.P.P., M.P., D.S., F.A., A.P., B.M., L.D., F.V.M., D.S., M.R., E.P.d.l.B., A.R., and R.V. have no competing interests to declare. B.L., R.M., and J.A.O. are full time employees of IB Biotech, the genetics company of the Instituto Bernabeu group, which performs preimplantation genetic testing. M.G. is a full time employee of Novagen, the genetics company of Cegyr, which performs preimplantation genetic testing., Trial Registration Number: N/A., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: In oocytes of advanced maternal age (AMA) women, what are the mechanisms leading to aneuploidy and what is the association of aneuploidy with embryo development?, Summary Answer: Known chromosome segregation errors such as precocious separation of sister chromatids explained 90.4% of abnormal chromosome copy numbers in polar bodies (PBs), underlying impaired embryo development., What Is Known Already: Meiotic chromosomal aneuploidies in oocytes correlate with AMA (>35 years) and can affect over half of oocytes in this age group. This underlies the rationale for PB biopsy as a form of early preimplantation genetic testing for aneuploidy (PGT-A), as performed in the 'ESHRE STudy into the Evaluation of oocyte Euploidy by Microarray analysis' (ESTEEM) randomized controlled trial (RCT). So far, chromosome analysis of oocytes and PBs has shown that precocious separation of sister chromatids (PSSC), Meiosis II (MII) non-disjunction (ND), and reverse segregation (RS) are the main mechanisms leading to aneuploidy in oocytes., Study Design, Size, Duration: Data were sourced from the ESTEEM study, a multicentre RCT from seven European centres to assess the clinical utility of PGT-A on PBs using array comparative genomic hybridization (aCGH) in patients of AMA (36-40 years). This included data on the chromosome complement in PB pairs (PGT-A group), and on embryo morphology in a subset of embryos, up to Day 6 post-insemination, from both the intervention (PB biopsy and PGT-A) and control groups., Participants/materials, Setting, Methods: ESTEEM recruited 396 AMA patients: 205 in the intervention group and 191 in the control group. Complete genetic data from 693 PB pairs were analysed. Additionally, the morphology from 1034 embryos generated from fertilized oocytes (two pronuclei) in the PB biopsy group and 1082 in the control group were used for statistical analysis., Main Results and the Role of Chance: Overall, 461/693 PB pairs showed abnormal segregation in 1162/10 810 chromosomes. The main observed abnormal segregations were compatible with PSSC in Meiosis I (MI) (n = 568/1162; 48.9%), ND of chromatids in MII or RS (n = 417/1162; 35.9%), and less frequently ND in MI (n = 65/1162; 5.6%). For 112 chromosomes (112/1162; 9.6%), we observed a chromosome copy number in the first PB (PB1) and second PB (PB2) that is not explained by any of the known mechanisms causing aneuploidy in oocytes. We observed that embryos in the PGT-A arm of the RCT did not have a significantly different morphology between 2 and 6 days post-insemination compared to the control group, indicating that PB biopsy did not affect embryo quality. Following age-adjusted multilevel mixed-effect ordinal logistic regression models performed for each embryo evaluation day, aneuploidy was associated with a decrease in embryo quality on Day 3 (adjusted odds ratio (aOR) 0.62, 95% CI 0.43-0.90), Day 4 (aOR 0.15, 95% CI 0.06-0.39), and Day 5 (aOR 0.28, 95% CI 0.14-0.58)., Limitations, Reason for Caution: RS cannot be distinguished from normal segregation or MII ND using aCGH. The observed segregations were based on the detected copy number of PB1 and PB2 only and were not confirmed by the analysis of embryos. The embryo morphology assessment was static and single observer., Wider Implications of the Findings: Our finding of frequent unexplained chromosome copy numbers in PBs indicates that our knowledge of the mechanisms causing aneuploidy in oocytes is incomplete. It challenges the dogma that aneuploidy in oocytes is exclusively caused by mis-segregation of chromosomes during MI and MII., Study Funding/competing Interest(s): Data were mined from a study funded by ESHRE. Illumina provided microarrays and other consumables necessary for aCGH testing of PBs. None of the authors have competing interests., Trial Registration Number: Data were mined from the ESTEEM study (ClinicalTrials.gov Identifier NCT01532284)., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To assess patients' and embryonic characteristics that may have an influence on the decision to transfer a mosaic embryo., Method: Single centre retrospective cohort study including 1247 PGT-A cycles. Demographic and clinical factors associated with a decision to transfer a mosaic embryo were studied. Female age, number of previous cycles, previous availability of euploid embryos, history of miscarriages and parity as well as percentage of mosaicism, type of anomaly and chromosome risk were studied in relation to decision-making. Outcomes after mosaic embryo transfer were assessed., Results: To date, in 7.9% of cycles (99/1247), patients have had to make a decision on the fate of their mosaic embryos. In 23.2% of cycles (23/99), patients decided to transfer. In most cases (79.8%; 79/99), patients underwent genetic counselling before the decision. None of the variables analysed were associated with the patients' decision, although parity and the high-degree mosaicism (>50%) seemed to be negatively associated with the decision to transfer (18.2% vs. 29.8%, p = 0.294; 10% vs. 32.2%, p = 0.052)., Conclusions: Neither reproductive history nor information on mosaic embryo characteristics through counselling seems to be determinative for patients when deciding to transfer a mosaic embryo. Promising and increasing data on clinical outcomes after mosaic embryo transfer will be of utmost importance to soften risk perception regarding mosaic embryos and give a better, simplified and more evidence-based counselling., (© 2022 John Wiley & Sons Ltd.)

Research Question: Is there any imbalance in the sex ratio at the blastocyst stage of human embryos? And what is the sex ratio in euploid, transferred, implanted blastocysts and at birth?, Design: Embryos from 646 women undergoing 921 preimplantation genetic testing for aneuploidy (PGT-A) cycles from September 2017 to February 2020 were included. Data from the chromosomal constitution of 2637 biopsied blastocysts were retrospectively analysed. Trophectoderm samples were analysed by next-generation sequencing. Embryos were categorized as euploid, mosaic or aneuploid. A total of 548 blastocysts diagnosed as euploid were warmed and transferred in a subsequent single-embryo transfer cycle., Results: The blastocyst sex ratio was skewed in favour of male sex with 53.1% (1401/2637) of blastocysts diagnosed as male and 46.9% (1236/2637) as female (sex ratio 1.13, 95% confidence interval [CI] 1.05-1.22). Following biopsy and PGT-A, 41.2% (1086/2637) of blastocysts were classified as euploid, 7.7% (202/2637) as mosaic and 51.2% (1349/2637) as aneuploid. More chromosome euploidy was observed among female than male blastocysts (adjusted odds ratio 1.29, 95% CI 1.08-1.55) after adjusting for female age, male age and gonadotrophin dose. Euploid blastocysts were comparable between the sexes (sex ratio 0.99, 95% CI 0.88-1.11). No significant differences were observed between the sexes in implantation (sex ratio 0.86, 95% CI 0.68-1.08), miscarriage (sex ratio 1, 95% CI 0.51-1.97) or live birth rate (sex ratio 0.85, 95% CI 0.66-1.08)., Conclusions: More male than female embryos develop to the blastocyst stage. Male blastocysts exhibit a higher aneuploidy rate. The capacity to implant and lead to a live birth is similar between the sexes., (Copyright © 2022 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Purpose: To determine whether embryo mosaicism prevalence in preimplantation genetic testing for aneuploidy (PGT-A) cycles is associated with the trophectoderm biopsy technique used (a. number of laser pulses or b. the use of flicking or pulling) or the time to tubing., Methods: Prospective observational study performed in a single IVF-PGT-A setting from May 2019 to May 2021. Trophectoderm biopsies were analysed by next-generation sequencing. Mosaicism was analysed in relation to the biopsy methodology (number of laser pulses and pulling vs flicking), time elapsed from biopsy to tubing (min), and time of sample cryostorage from tubing to amplification (days). As a secondary objective, the number of laser pulses and biopsy methodology were studied in relation to clinical outcomes of transferred euploid blastocysts., Results: None of the analysed variables were associated to mosaicism prevalence. Multivariable regression analysis demonstrated that mosaicism prevalence was comparable either when  > 3 laser pulses were used as compared to ≤ 3 (13.9% vs 13.8%, aOR = 0.8726 [0.60-1.28]) and pulling compared to flicking (13.1% vs 14.0%, aOR = 0.86 [0.60-1.23]). Moreover, neither the number of laser pulses during biopsy (> 3 vs ≤ 3) nor the technique used (pulling vs flicking) were associated with clinical pregnancy after the transfer of frozen-thawed euploid blastocysts (54.9% vs 55.2%, aOR = 1.05 [0.53-2.09]; 61.1% vs 52.9%, aOR = 1.11 [0.55-2.25], respectively)., Conclusion: Our results suggest that, as long as the biopsy and tubing procedures are performed following standardized high quality procedures, no specific approach would increase the generation of artefactual mosaicism as a result of trophectoderm biopsy. Trophectoderm biopsies should be performed regardless of the methodology but always aiming on minimising blastocyst manipulation., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Research Question: Are intrinsic or extrinsic factors associated with embryo mosaicism prevalence in IVF cycles?, Design: Retrospective cohort study of preimplantation genetic testing for aneuploidy (PGT-A) cycles carried out at a university-affiliated IVF clinic between October 2017 and October 2019. Trophectoderm biopsies were analysed by next generation sequencing. Mosaicism prevalence, type of anomaly and the chromosomes involved were analysed. Intrinsic and extrinsic factors potentially inducing mosaicism were studied: maternal and paternal age, antral follicle count, cumulus-oocyte complexes retrieved, female body mass index, PGT-A indication, sperm concentration, total dosage of gonadotrophins, embryo quality and day of blastocyst formation, single-step commercial media used and biopsy operator., Results: Overall prevalence of mosaicism in our PGT-A setting was 13.9%. In segmental mosaicism, larger chromosomes tended to be more affected, which was not observed in whole-chromosome mosaicism. Additionally, segmental mosaicism was mostly observed in monosomy (69.6%; P < 0.01) compared with whole-chromosome mosaicism (49.7% monosomies versus 50.3% trisomies; P = 0.83). Although a high inter-patient variability was observed, only paternal age showed a positive association with mosaicism (adjusted OR 1.26, 95% CI 1.02 to 1.54) among the analysed variables., Conclusions: Our results suggest remarkable differences in the mechanisms generating segmental and whole-chromosome mosaicism, indicating that they may deserve different consideration when studying them and when prioritizing them for transfer. Male factor seems to be associated with mosaicism and may be worthy of specific assessment in future studies., (Copyright © 2020 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Objective: What are the cost per live birth and the incremental cost of preventing a miscarriage with preimplantation genetic testing for aneuploidy (PGT-A) by polar body biopsy and array-based comprehensive genome hybridisation (aCGH) versus regular IVF/ICSI without PGT-A for infertility treatment in women 36-40 years of age?, Design: Decision tree model., Population: A randomised clinical trial on PGT-A (ESTEEM study)., Methods: Two treatment strategies were compared: one cycle of IVF/ICSI with or without PGT-A. Costs and effects were analysed with this model for four different cost scenarios: high-, higher medium, lower medium and low-cost. Base case, sensitivity, threshold, and probabilistic sensitivity analyses were used to examine the cost-effectiveness implications of PGT-A., Results: PGT-A increased the cost per live birth by approximately 15% in the high-cost scenario to approximately 285% in the low-cost scenario. Threshold analysis revealed that PGT-A would need to be associated with an absolute increase in pregnancy rate by 6% to >39% or, alternatively, would need to be US$2,969 (high-cost scenario) to US$4,888 (low-cost scenario) cheaper. The incremental cost to prevent one miscarriage by PGT-A using the base case assumptions was calculated to be US$34,427 (high-cost scenario) to US$51,146 (low-cost scenario). A probabilistic sensitivity analysis showed cost-effectiveness for PGT-A from 1.9% (high-cost scenario) to 0.0% (low-cost scenario) of calculated samples., Conclusions: While avoiding unnecessary embryo transfers and miscarriages are important goals, patients and doctors need to be aware of the high-cost implications of applying PGT-A using aCGH on polar bodies., Tweetable Abstract: PGT-A by polar body biopsy and comprehensive genome hybridisation increases cost per live birth and requires high financial spending per miscarriage averted., (© 2020 Royal College of Obstetricians and Gynaecologists.)

The transition in biopsy timing from blastomere to trophectoderm biopsy has led to a remarkable decrease in the percentage of undiagnosed blastocysts. However, patients with few or no euploid blastocysts can be affected by this residual percentage of diagnosis failure. The aim of this study is to assess whether blastocyst rebiopsy and revitrification is an efficient and safe procedure to be applied in cases of no results after analysis. Fifty-three patients agreed to the warming of 61 blastocysts to perform a second biopsy and PGT-A by aCGH. Only 75.4% of the blastocysts survived, reexpanded, and could be rebiopsied. After the second biopsy and analysis, 95.6% of the blastocysts were successfully diagnosed with an euploidy rate of 65.9%. Eighteen euploid blastocysts were warmed and transferred to 18 patients with a 100% survival and reexpansion rate. Seven clinical pregnancies have been achieved with 4 live births, 1 ongoing pregnancy, and 2 miscarriages. Thus, although few transfers of rebiopsied and revitrified blastocysts have been performed till date, our preliminary results show that this approach is efficient and safe to be applied for undiagnosed blastocysts, as it ultimately allows the transfer of euploid blastocysts and good clinical outcomes.

This retrospective study was carried out to determine which strategy is associated with improved outcomes in two back-to-back cycles when undergoing embryo accumulation. Eighty patients with two stimulation cycles performed with <45 days between retrievals between Jan'16-Mar'17 were included. Patients were segregated according to the strategy used to link stimulations: spontaneous menses (SM), vaginal micronized progesterone (VMP) or oral contraceptive pills (OCP). Main outcome measure was oocytes retrieved. The oocytes retrieved difference between cycles was -0.9 in SM, -1.5 in VMP and +0.4 in OCPs. Although not statistically significant, more oocytes retrieved were observed in the 2ndcycle when OCPs were used (9.0 ± 3.7 vs. 9.4 ± 4.1)? whereas fewer oocytes retrieved were observed when SM (9.4 ± 3.9 vs. 8.5 ± .0) or VMP (9.8 ± 5.7 vs. 8.2 ± 4.4) were used. After adjusting for age, gonadotropins and stimulation days (2nd cycle) and treatment group in an ANCOVA model, no treatment was associated with a higher average number of oocytes retrieved (power: 14.9%) or a higher difference of oocytes retrieved (power: 22.3%). Although no statistical significance was reached, OCPs were observed to achieve higher average and positive difference of oocytes retrieved in the 2nd cycle.

SummaryShortly after the implementation of comprehensive chromosome screening (CCS) techniques for preimplantation genetic testing for aneuploidies (PGT-A), the discussion about the transition from day 3 to blastocyst stage biopsy was initiated. Trophectoderm biopsy with CCS is meant to overcome the limitations of cleavage-stage biopsy and single-cell analysis. The aim of this study was to assess the results obtained in our PGT-A programme after the implementation of this new strategy. Comparisons between the results obtained in 179 PGT-A cycles with day 3 biopsy (D+3) and fresh embryo transfer, and 204 cycles with trophectoderm biopsy and deferred (frozen-thawed) embryo transfer were established. Fewer embryos were biopsied and a higher euploidy rate was observed in the trophectoderm biopsy group. No differences in implantation (50.3% vs. 61.4%) and clinical pregnancy rate per transfer (56.1% vs. 65.3%) were found. Although the mean number of euploid embryos per cycle did not differ between groups (1.5 ± 1.7 vs. 1.7 ± 1.8), the final number of euploid blastocysts available for transfer per cycle was significantly higher in the trophectoderm biopsy group (1.1 ± 1.3 vs. 1.7 ± 1.8). This factor led to an increased cumulative live birth rate in this last group (34.1% vs. 44.6%). Although both strategies can offer good results, trophectoderm biopsy offers a more robust diagnosis and the intervention is less harmful for the embryos so more euploid blastocysts are finally available for transfer and/or vitrification.

Purpose: The purpose of this study was to investigate the chromosomal constitution and the developmental potential of intracytoplasmic sperm injection (ICSI) deriving embryos displaying a single pronucleus at the zygote stage., Methods: Eighty-eight embryos from single pronucleus (1PN) two polar bodies (2PB) ICSI zygotes from 64 preimplantational genetic screening (PGS) cycles (October 2012-December 2014), were retrospectively analyzed. Zygotes were cultured in a time-lapse incubator. Embryo biopsy was performed on day 3 and genetic analysis approached by array comparative genomic hybridization., Results: Chromosomal analysis revealed that 17% (15/88) of embryos derived from 1PN 2PB zygotes were diagnosed as euploid. After blastomere biopsy at day 3, the blastocyst rate at day 5 was 3.4% (3/88). Only 2.3% (2/88) euploid blastocysts were obtained. In two couples and after counseling and patient agreement, the transfer of a euploid blastocyst from a 1PN 2PB ICSI zygote was performed resulting in the birth of a healthy child., Conclusions: These results open the possibility to consider embryos coming from 1PN 2PB ICSI zygotes for transfer when no other embryos from 2PN 2PB ICSI zygotes are available and if a PGS diagnosis of euploidy is obtained. Confirmation of biparental inheritance is strongly recommended.

This is an observational study of the response to ovarian stimulation and preimplantational genetic screening (PGS) cycles of 188 patients with a foreseen high aneuploid rate, undergoing two or three stimulation cycles (2SC and 3SC) and oocyte vitrification to accumulate oocytes (Accumulation group = 112 patients) compared to patients undergoing one stimulation cycle (1SC Group= 76 patients) and fresh embryo transfer, between January 2011 and July 2014. Accumulation was performed when <10 MII oocytes were retrieved. Oocytes were vitrified for later warming and IVF, when the planned number of oocytes was achieved. After PGS, euploid embryos were transferred. Comparing 2SC Group with 3SC Group, AMH, AFC, number of oocytes retrieved per pick-up and total number of biopsied embryos were significantly higher in the 2SC Group. After chromosome analysis, 18.5% of biopsied embryos were euploid and 58.9% patients reached embryo transfer. There were no differences in pregnancy rates per patient between the 1SC, 2SC and 3SC Groups (36.8%, 34.9% and 31.0%, respectively) or per embryo transfer (59.6, 56.8 and 60%, respectively). In patients with <10 MII oocytes after ovarian stimulation undergoing PGS, accumulating oocytes can render a pregnancy rate per patient and per embryo transfer comparable to those of fresh PGS cycles.

Comprehensive chromosome analysis techniques such as metaphase-Comparative Genomic Hybridisation (CGH) and array-CGH are available for single-cell analysis. However, while metaphase-CGH and BAC array-CGH have been widely used for Preimplantation Genetic Diagnosis, oligonucleotide array-CGH has not been used in an extensive way. A comparison between oligonucleotide array-CGH and metaphase-CGH has been performed analysing 15 single fibroblasts from aneuploid cell-lines and 18 single blastomeres from human cleavage-stage embryos. Afterwards, oligonucleotide array-CGH and BAC array-CGH were also compared analysing 16 single blastomeres from human cleavage-stage embryos. All three comprehensive analysis techniques provided broadly similar cytogenetic profiles; however, non-identical profiles appeared when extensive aneuploidies were present in a cell. Both array techniques provided an optimised analysis procedure and a higher resolution than metaphase-CGH. Moreover, oligonucleotide array-CGH was able to define extra segmental imbalances in 14.7% of the blastomeres and it better determined the specific unbalanced chromosome regions due to a higher resolution of the technique (≈ 20 kb). Applicability of oligonucleotide array-CGH for Preimplantation Genetic Diagnosis has been demonstrated in two cases of Robertsonian translocation carriers 45,XY,der(13;14)(q10;q10). Transfer of euploid embryos was performed in both cases and pregnancy was achieved by one of the couples. This is the first time that an oligonucleotide array-CGH approach has been successfully applied to Preimplantation Genetic Diagnosis for balanced chromosome rearrangement carriers.

Objective: To study the chromosome constitution and in vitro development of embryos derived from monopronucleated (1PN) zygotes after intracytoplasmic sperm injection (ICSI)., Design: Prospective study., Setting: Private assisted reproduction center., Patient(s): Fifty-four 1PN 2PB zygotes obtained from 48 ICSI cycles., Intervention(s): Pronuclear diameter measured 18 ± 2 hours after ICSI and embryonic in vitro development assessed until the blastocyst stage or arrest; embryos disaggregated and all cells analyzed for chromosomes 13, 18, 21, X, and Y by fluorescent in situ hybridization (FISH)., Main Outcome Measure(s): Pronuclear size, in vitro embryo development, and cytogenetic characteristics., Result(s): All the embryos were chromosomally abnormal (7.4% diploid mosaic, 16.7% haploid mosaics, 5.5% aneuploid mosaic, and 70.4% chaotic mosaic), and 35.2% showed a Y chromosome. No difference in the pronuclear size was observed according to the type of abnormality. Only 7.4% of the embryos resulted in blastocysts with good morphologic features., Conclusion(s): Despite showing only one pronucleus, most of the zygotes resulted from fertilization. Embryos derived from 1PN ICSI zygotes are chromosomally abnormal. Neither the pronuclear size nor the in vitro developmental ability of these embryos can be predictive of their chromosomal constitution. According to our results, embryos that develop from 1PN ICSI zygotes should be discarded for any reproductive purpose., (Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Embryos diagnosed as abnormal in Preimplantation Genetic Diagnosis (PGD) cycles are useful for the establishment of human Embryonic Stem Cells (hESC) lines with genetic disorders. These lines can be helpful for drug screening and for the development of new treatments. Vitrification has proved to be an efficient method to preserve human blastocysts. One hundred and three abnormal or undiagnosed vitrified blastocysts from the PGD programme at Institut Universitari Dexeus were donated for human embryonic stem cell derivation. The overall survival rate after warming was 70.6 %. Our results showed better survival rates when blastocysts have not started the hatching process (initial/expanded 87.8 %, hatching 68.3 % and hatched 27.3 %). Thirty-five blastocysts and 12 partially surviving embryos were seeded. One hESC line with the multiple exostoses type 2 paternal mutation was obtained.

Indications and candidates for preimplantation genetic diagnosis (PGD) have increased in recent years. This study evaluates whether IVF-intracytoplasmic sperm injection (ICSI) results could be improved by selecting embryos through PGD-AS (aneuploidy screening) in couples in whom the male partner presents meiotic abnormalities. Two hundred and fifty-six embryos were biopsied and 183 were suitable for analysis (73.2%). Ninety-two embryos showed normal chromosomal analysis (50.3% of the analysed embryos and 57.5% of the diagnosed embryos). Pregnancy, abortion and implantation rates were compared with 66 IVF-ICSI cycles performed in 44 patients with meiotic abnormalities without PGD (control group). No statistically significant differences in the pregnancy rate (52 versus 43.9%), implantation rate (32.1 versus 23.5%) and miscarriage rate (15.4 versus 10.3%) were observed between the groups. Although the embryos obtained from men with meiotic abnormalities showed a high frequency of chromosome abnormalities, no improvements in pregnancy and implantation rates were obtained after PGD-AS in the series analysed.