The unknown human trophectoderm: implication for biopsy at the blastocyst stage

Non-Invasive Pre-implantation Genetic Testing's Reliability for Aneuploidy using Cell-free DNA in Embryo Culture Media

OBJECTIVE

The presence of embryonic cell-free DNA (cfDNA) in spent embryo culture media (SECM) may offer valuable advantages for non-invasive testing of embryo ploidy or genetic characteristics compared to trophectoderm (TE) biopsy. This study aimed to assess the diagnostic potential of SECM cfDNA as a non-invasive sample for chromosomal copy number testing in blastocysts within the clinical setting of in-vitro fertilization.

METHOD

This prospective observational study collected 28 SECM cfDNA samples which were matched with TE biopsy samples from 21 infertile couples who underwent IVF-PGT-A cycles. SECM samples were obtained from blastocysts that were cultured for approximately 5/6 days in an uninterrupted time-lapse incubator. Both sets of samples were collected during the biopsy procedure. The Variseq Illumina platform was utilized for ploidy measurement. The study evaluated the informativity and interpretability of SECM cfDNA, concordance of general ploidy status, and sex chromosome agreement between the two sample types.

RESULTS

SECM cfDNA had a high informativity rate (100%) after double amplification procedure, with a result interpretability of 93%. Two out of the 28 SECM cfDNA samples were uninterpretable and regarded as overall noise samples. The diagnostic potential of SECM cfDNA, when compared to TE biopsy the standard reference, was relatively low at 53%. Maternal DNA contamination remains the major obstacle that hinders the widespread clinical adoption of SECM cfDNA in the routine practice of pre-implantation genetic testing for aneuploidy within IVF settings.

CONCLUSION

A significant modification must be implemented in the IVF laboratory to minimize DNA contamination and this necessitates suggesting adjustments to oocyte denudation, embryo culture media preparation, and sample collection procedures.

Metabolic Profiles of Offspring Born From Biopsied Embryos from Toddlerhood to Preschool Age

CONTEXT

Embryo biopsy, which is necessary for preimplantation genetic testing (PGT), has not been fully investigated regarding its potential influences and safety. Previous studies of children born from biopsied embryos (PGT children) have primarily centered around their growth and neuropsychological development, while there remains limited knowledge concerning their endocrine and metabolic parameters.

OBJECTIVE

This study aims to examine the effect of trophectoderm (TE) biopsy on metabolic outcomes for PGT children.

METHODS

A total of 1267 children from the Center for Reproductive Medicine, Shandong University, who were conceived through in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) with and without PGT, were analyzed in this study. Three sets of measurements pertaining to growth and metabolism were taken at each predetermined follow-up time point. The linear regression models within a generalized estimating equation were employed to examine the associations between the PGT and each outcome measure and the approach of false discovery rate was used to correct for multiple comparisons.

RESULTS

After controlling for confounding factors and correcting for multiple comparisons, no statistically significant difference was identified in any of the measured variables between the PGT children and children conceived by IVF alone (IVF children) and children conceived through IVF using ICSI (ICSI children). The same is true also for age- or sex-based subgroup analyses.

CONCLUSION

Between the ages of 1 and 5 years, there are no clinically adverse metabolic outcomes observed in PGT children, and their metabolic profiles are essentially identical to those of IVF children and ICSI children.

Trophectoderm cells of human mosaic embryos display increased apoptotic levels and impaired differentiation capacity: a molecular clue regarding their reproductive fate?

STUDY QUESTION

Are there cell lineage-related differences in the apoptotic rates and differentiation capacity of human blastocysts diagnosed as euploid, mosaic, and aneuploid after preimplantation genetic testing for aneuploidy (PGT-A) based on concurrent copy number and genotyping analysis?

SUMMARY ANSWER

Trophectoderm (TE) cells of mosaic and aneuploid blastocysts exhibit significantly higher levels of apoptosis and significantly reduced differentiation capacity compared to those of euploid blastocysts.

WHAT IS KNOWN ALREADY

Embryos diagnosed as mosaic after PGT-A can develop into healthy infants, yet understanding the reasons behind their reproductive potential requires further research. One hypothesis suggests that mosaicism can be normalized through selective apoptosis and reduced proliferation of aneuploid cells, but direct evidence of these mechanisms in human embryos is lacking. Additionally, data interpretation from studies involving mosaic embryos has been hampered by retrospective analysis methods and the high incidence of false-positive mosaic diagnoses stemming from the use of poorly specific PGT-A platforms.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study performing colocalization of cell-lineage and apoptotic markers by immunofluorescence (IF). We included a total of 64 human blastocysts donated to research on Day 5 or 6 post-fertilization (dpf) by 43 couples who underwent in vitro fertilization treatment with PGT-A at IVI-RMA Valencia between September 2019 and October 2022. A total of 27 mosaic blastocysts were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study consisted of two phases: Phase I (caspase-3, n = 53 blastocysts): n = 13 euploid, n = 22 mosaic, n = 18 aneuploid. Phase II (terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), n = 11 blastocysts): n = 2 euploid, n = 5 mosaic, n = 4 aneuploid. Following donation for research, vitrified blastocysts were warmed, cultured until re-expansion, fixed, processed for IF, and imaged using confocal microscopy. For each blastocyst, the following cell counts were conducted: total cells (DAPI+), TE cells (GATA3+), inner cell mass (ICM) cells (GATA3-/NANOG+), and apoptotic cells (caspase-3+ or TUNEL+). The incidence of apoptosis was calculated for each blastocyst by dividing the number of caspase-3+ cells (Phase I) or TUNEL+ cells (Phase II) by the number of TE or ICM cells. Statistical analysis was performed according to data type and distribution (P < 0.05 was considered statistically significant).

MAIN RESULTS AND THE ROLE OF CHANCE

Phase I: Mosaic blastocysts displayed a similar number of total cells (49.6 ± 15 cells at 5 dpf; 58.8 ± 16.9 cells at 6 dpf), TE cells (38.8 ± 13.7 cells at 5 dpf; 49.2 ± 16.2 cells at 6 dpf), and ICM cells (10.9 ± 4.2 cells at 5 dpf; 9.7 ± 7.1 cells at 6 dpf) compared to euploid and aneuploid blastocysts (P > 0.05). The proportion of TE cells retaining NANOG expression increased gradually from euploid blastocysts (9.7% = 63/651 cells at 5 dpf; 0% = 0/157 cells at 6 dpf) to mosaic blastocysts (13.1% = 104/794 cells at 5 dpf; 3.4% = 12/353 cells at 6 dpf) and aneuploid blastocysts (27.9% = 149/534 cells at 5 dpf; 4.6% = 19/417 cells at 6 dpf) (P < 0.05). At the TE level, caspase-3+ cells were frequently observed (39% = 901/2310 cells). The proportion of caspase-3+ TE cells was significantly higher in mosaic blastocysts (44.1% ± 19.6 at 5 dpf; 43% ± 16.8 at 6 dpf) and aneuploid blastocysts (45.9% ± 16.1 at 5 dpf; 49% ± 15.1 at 6 dpf) compared to euploid blastocysts (26.6% ± 16.6 at 5 dpf; 17.5% ± 14.8 at 6 dpf) (P < 0.05). In contrast, at the ICM level, caspase-3+ cells were rarely observed (1.9% = 11/596 cells), and only detected in mosaic blastocysts (2.6% = 6/232 cells) and aneuploid blastocysts (2.5% = 5/197 cells) (P > 0.05). Phase II: Consistently, TUNEL+ cells were only observed in TE cells (32.4% = 124/383 cells). An increasing trend was identified toward a higher proportion of TUNEL+ cells in the TE of mosaic blastocysts (37.2% ± 21.9) and aneuploid blastocysts (39% ± 41.7), compared to euploid blastocysts (23% ± 32.5), although these differences did not reach statistical significance (P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

The observed effects on apoptosis and differentiation may not be exclusive to aneuploid cells. Additionally, variations in aneuploidies and unexplored factors related to blastocyst development and karyotype concordance may introduce potential biases and uncertainties in the results.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate a cell lineage-specific effect of aneuploidy on the apoptotic levels and differentiation capacity of human blastocysts. This contributes to unravelling the biological characteristics of mosaic blastocysts and supports the concept of clonal depletion of aneuploid cells in explaining their reproductive potential.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by grants from Centro para el Desarrollo Tecnológico Industrial (CDTI) (20190022) and Generalitat Valenciana (APOTIP/2019/009). None of the authors has any conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Long-term health risk of offspring born from assisted reproductive technologies

Since the world's first in vitro fertilization baby was born in 1978, there have been more than 8 million children conceived through assisted reproductive technologies (ART) worldwide, and a significant proportion of them have reached puberty or young adulthood. Many studies have found that ART increases the risk of adverse perinatal outcomes, including preterm birth, low birth weight, small size for gestational age, perinatal mortality, and congenital anomalies. However, data regarding the long-term outcomes of ART offspring are limited. According to the developmental origins of health and disease theory, adverse environments during early life stages may induce adaptive changes and subsequently result in an increased risk of diseases in later life. Increasing evidence also suggests that ART offspring are predisposed to an increased risk of non-communicable diseases, such as malignancies, asthma, obesity, metabolic syndrome, diabetes, cardiovascular diseases, and neurodevelopmental and psychiatric disorders. In this review, we summarize the risks for long-term health in ART offspring, discuss the underlying mechanisms, including underlying parental infertility, epigenetic alterations, non-physiological hormone levels, and placental dysfunction, and propose potential strategies to optimize the management of ART and health care of parents and children to eliminate the associated risks. Further ongoing follow-up and research are warranted to determine the effects of ART on the long-term health of ART offspring in later life.

Embryo drop-out rates in preimplantation genetic testing for aneuploidy (PGT-A): a retrospective data analysis from the DoLoRes study

PURPOSE

To evaluate the decline in transferable embryos in preimplantation genetic testing for aneuploidy (PGT-A) cycles due to (a) non-biopsable blastocyst quality, (b) failure of genetic analysis, (c) diagnosis of uniform numerical or structural chromosomal aberrations, and/or (d) chromosomal aberrations in mosaic constitution.

METHODS

This retrospective multicenter study comprised outcomes of 1562 blastocysts originating from 363 controlled ovarian stimulation cycles, respectively, 226 IVF couples in the period between January 2016 and December 2018. Inclusion criteria were PGT-A cycles with trophectoderm biopsy (TB) and next generation sequencing (NGS).

RESULTS

Out of 1562 blastocysts, 25.8% were lost due to non-biopsable and/or non-freezable embryo quality. In 10.3% of all biopsied blastocysts, genetic analysis failed. After exclusion of embryos with uniform or chromosomal aberrations in mosaic, only 18.1% of those originally yielded remained as diagnosed euploid embryos suitable for transfer. This translates into 50.4% of patients and 57.6% of stimulated cycles with no euploid embryo left for transfer. The risk that no transfer can take place rose significantly with a lower number of oocytes and with increasing maternal age. The chance for at least one euploid blastocyst/cycle in advanced maternal age (AMA)-patients was 33.3% compared to 52.1% in recurrent miscarriage (RM), 59.8% in recurrent implantation failure (RIF), and 60.0% in severe male factor (SMF).

CONCLUSIONS

The present study demonstrates that PGT-A is accompanied by high embryo drop-out rates. IVF-practitioners should be aware that their patients run a high risk of ending up without any embryo suitable for transfer after (several) stimulation cycles, especially in AMA patients. Patients should be informed in detail about the frequency of inconclusive or mosaic results, with the associated risk of not having an euploid embryo available for transfer after PGT-A, as well as the high cost involved in this type of testing.

Effectiveness of non-invasive chromosomal screening for normal karyotype and chromosomal rearrangements

Purpose: To study the accuracy of non-invasive chromosomal screening (NICS) results, in normal chromosomes and chromosomal rearrangement groups and to investigate whether using trophoblast cell biopsy along with NICS, to choose embryos for transfer can improve the clinical outcomes of assisted pregnancy.

Methods: We retrospectively analyzed 101 couples who underwent preimplantation genetic testing at our center from January 2019 to June 2021 and collected 492 blastocysts for trophocyte (TE) biopsy. D3-5 blastocyst culture fluid and blastocyst cavity fluid were collected for the NICS. Amongst them, 278 blastocysts (58 couples) and 214 blastocysts (43 couples) were included in the normal chromosomes and chromosomal rearrangement groups, respectively. Couples undergoing embryo transfer were divided into group A, in which both the NICS and TE biopsy results were euploid (52 embryos), and group B, in which the TE biopsy results were euploid and the NICS results were aneuploid (33 embryos).

Results: In the normal karyotype group, concordance for embryo ploidy was 78.1%, sensitivity was 94.9%, specificity was 51.4%, the positive predictive value (PPV) was 75.7%, and the negative predictive value (NPV) was 86.4%. In the chromosomal rearrangement group, concordance for embryo ploidy was 73.1%, sensitivity was 93.3%, specificity was 53.3%, the PPV was 66.3%, and the NPV was 89%. In euploid TE/euploid NICS group, 52 embryos were transferred; the clinical pregnancy rate was 71.2%, miscarriage rate was 5.4%, and ongoing pregnancy rate was 67.3%. In euploid TE/aneuploid NICS group, 33 embryos were transferred; the clinic pregnancy rate was 54.5%, miscarriage rate was 5.6%, and ongoingpregnancy rate was 51.5%. The clinical pregnancy and ongoing pregnancy rates were higher in the TE and NICS euploid group.

Conclusion: NICS was similarly effective in assessing both normal and abnormal populations. Identification of euploidy and aneuploidy alone may lead to the wastage of embryos due to high false positives. More suitable reporting methods for NICS and countermeasures for a high number of false positives in NICS are needed. In summary, our results suggest that combining biopsy and NICS results could improve the outcomes of assisted pregnancy.

Biophysical models of early mammalian embryogenesis

Embryo development is a critical and fascinating stage in the life cycle of many organisms. Despite decades of research, the earliest stages of mammalian embryogenesis are still poorly understood, caused by a scarcity of high-resolution spatial and temporal data, the use of only a few model organisms, and a paucity of truly multidisciplinary approaches that combine biological research with biophysical modeling and computational simulation. Here, we explain the theoretical frameworks and biophysical processes that are best suited to modeling the early mammalian embryo, review a comprehensive list of previous models, and discuss the most promising avenues for future work.

The impact of blastocyst freezing and biopsy on the association of blastocyst morphological parameters with live birth and singleton birthweight

OBJECTIVE

To explore whether the associations of 3 blastocyst morphological parameters, namely, degree of blastocyst expansion (expansion), appearance of trophectoderm (TE) and inner cell mass, with live birth and singleton birth weight are influenced by blastocyst freezing and biopsy.

DESIGN

A retrospective study.

SETTING

An assisted reproductive technology center.

PATIENT(S)

28,515 single blastocyst transfer cycles between January 2014 and August 2019.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Live birth and singleton birth weight.

RESULT(S)

Blastocyst transfer cycles were divided into 4 groups: biopsied blastocyst cycles (biopsied-blast), thawed blastocyst cycles (thawed-blast), blastocyst from thawed cleavage embryo cycles (blast-thawed-D3), and fresh blastocyst cycles (fresh-blast). Subgroup analyses by blastocyst stage (day 5 and day 6) were performed in thawed-blast and blast-thawed-D3. Because almost all blastocysts were biopsied on day 6 and fresh blastocysts were transferred on day 5, the biopsied-blast and fresh-blast were not divided into subgroups. First, the associations between blastocyst morphological parameters and live birth were analyzed. To explore the effect of freezing, we compared day-5 frozen cycles (thawed-blast) vs. day-5 fresh cycles (including fresh-blast and blast-thawed-D3) and day 6 frozen cycles (thawed-blast) vs. day-6 fresh cycles (blast-thawed-D3). Inner cell mass and TE were associated with live birth for day 5 embryos, and only TE affected live birth for day-6 embryos. The associations were the same in frozen cycles and fresh cycles. To explore the effect of biopsy, we compared day-6 biopsied cycles (biopsied-blast) vs. day-6 nonbiopsied cycles (including thawed-blast and blast-thawed-D3). All the 3 parameters were associated with live birth in biopsied-blast, whereas only TE was associated with live birth in nonbiopsied cycles. In addition, the associations between blastocyst morphological parameters and singleton birthweight were analyzed. In the 6 subgroups, expansion stage of day-6 embryos in biopsied-blast and TE grade of day-6 embryos in thawed-blast were associated with birth weight, and there are no associations in other subgroups.

CONCLUSION(S)

The association of blastocyst morphological parameters with live birth may be affected by blastocyst biopsy and/or genetic testing, and its association with birth weight may be affected by blastocyst freezing and biopsy and/or genetic testing.

An Update on Non-invasive Approaches for Genetic Testing of the Preimplantation Embryo

Preimplantation Genetic Testing (PGT) aims to reduce the chance of an affected pregnancy or improve success in an assisted reproduction cycle. Since the first established pregnancies in 1990, methodological approaches have greatly evolved, combined with significant advances in the embryological laboratory. The application of preimplantation testing has expanded, while the accuracy and reliability of monogenic and chromosomal analysis have improved. The procedure traditionally employs an invasive approach to assess the nucleic acid content of embryos. All biopsy procedures require high technical skill, and costly equipment, and may impact both the accuracy of genetic testing and embryo viability. To overcome these limitations, many researchers have focused on the analysis of cell-free DNA (cfDNA) at the preimplantation stage, sampled either from the blastocoel or embryo culture media, to determine the genetic status of the embryo non-invasively. Studies have assessed the origin of cfDNA and its application in non-invasive testing for monogenic disease and chromosomal aneuploidies. Herein, we discuss the state-of-the-art for modern non-invasive embryonic genetic material assessment in the context of PGT. The results are difficult to integrate due to numerous methodological differences between the studies, while further work is required to assess the suitability of cfDNA analysis for clinical application.

Comment on the recent PGDIS Position Statement on the Transfer of Mosaic Embryos 2021

The worldwide demand of preimplantation genetic testing for aneuploidy (PGT-A) is still growing. However, chromosomal mosaic results greatly challenge the clinical practice. The recently published PGDIS Position Statement on the Transfer of Mosaic Embryos is the third PGDIS position statement on how to deal with embryos diagnosed as chromosomal mosaics (CM) and, one of many attempts of different societies and working groups to provide a guideline for clinicians, laboratories, clinics, and genetic counselors. But still, as in previous statements, many issues remained unresolved. Moreover, from our point of view, the question how to deal with embryos diagnosed as CM, consisting of two or more karyological cell lines cannot be separated from all the other aspects of PGT-A including its accuracy. The paucity of clearcut indications for PGT-A and evidence of benefit as well as an overall cost-benefit assessment is given below.

Epidermal growth factor induces a trophectoderm lineage transcriptome resembling that of human embryos during reconstruction of blastoids from extended pluripotent stem cells

Objectives

This study aims to optimize the human extended pluripotent stem cell (EPSC) to trophectoderm (TE)‐like cell induction with addition of EGF and improve the quality of the reconstructing blastoids.

Materials and Methods

TE‐like cells were differentiated from human EPSCs. RNA‐seq data analysis was performed to compare with TE‐like cells from multiple human pluripotent stem cells (hPSCs) and embryos. A small‐scale compound selection was performed for optimizing the TE‐like cell induction and the efficiency was characterized using TE‐lineage markers expression by immunofluorescence stanning. Blastoids were generated by using the optimized TE‐like cells and the undifferentiated human EPSCs through three‐dimensional culture system. Single‐cell RNA sequencing was performed to investigate the lineage segregation of the optimized blastoids to human blastocysts.

Results

TE‐like cells derived from human EPSCs exhibited similar transcriptome with TE cells from embryos. Additionally, TE‐like cells from multiple naive hPSCs exhibited heterogeneous gene expression patterns and signalling pathways because of the incomplete silencing of naive‐specific genes and loss of imprinting. Furthermore, with the addition of EGF, TE‐like cells derived from human EPSCs enhanced the TE lineage‐related signalling pathways and exhibited more similar transcriptome to human embryos. Through resembling with undifferentiated human EPSCs, we elevated the quality and efficiency of reconstructing blastoids and separated more lineage cells with precise temporal and spatial expression, especially the PE lineage.

Conclusion

Addition of EGF enhanced TE lineage differentiation and human blastoids reconstruction. The optimized blastoids could be used as a blastocyst model for simulating early embryonic development.

Polygenic risk score for embryo selection—not ready for prime time

Numerous chronic diseases have a substantial hereditary component. Recent advances in human genetics have allowed the extent of this to be quantified via genome-wide association studies, producing polygenic risk scores (PRS), which can then be applied to individuals to estimate their risk of developing a disease in question. This technology has recently been applied to embryo selection in the setting of IVF and preimplantation genetic testing, with limited data to support its utility. Furthermore, there are concerns that the inherent limitations of PRS makes it ill-suited for use as a screening test in this setting. There are also serious ethical and moral questions associated with this technology that are yet to be addressed. We conclude that further research and ethical reflection are required before embryo selection based on PRS is offered to patients outside of the research setting.

The safety of VASApos presumptive adult ovarian stem cells

Isolation and characterization of presumptive human adult ovarian stem cells (OSC) has broken the long standing dogma of the absence of postnatal neo-oogenesis. Human adult OSC have been immunosorted by antibodies reacting against the RNA helicase VASA and have been reported to engraft into appropriate stem cell niches to promote neo-oogenesis. Analysis of published research, however, questions some of the findings on isolation, characterization, in-vitro self-renewal and clinical safety of the presumptive human adult OSC. In the present study, human VASA^pos embryo-fetal primordial germ cells and presumptive adult OSC are shown to share several pluripotency and early germ cell markers not ascertained in the initial characterization of adult OSC. A new hypothesis is made that the restoration of fertility claimed to result from presumptive human adult OSC may be attributed instead to VASA^pos embryo-fetal primordial germ cell remnants in the adult ovary, or alternatively to earlier VASA^neg germ cells generated by in-vitro de-differentiation of the presumptive OSC. The suggested hypotheses have extensive implications for the practice and safety of adult OSC in the development of new treatments aimed at rescuing the ovarian reserve.

Hypothesis: human trophectoderm biopsy downregulates the expression of the placental growth factor gene

Preeclampsia (PE) and intrauterine growth retardation (IUGR) are the results of defective placentation associated with the downregulation of different genes in the human trophoblast including the Placental Growth Factor (PGF). TrophEctoderm (TE) biopsy is increasingly performed for Pre-implantation Genetic Testing of Aneuploidies and it involves the traumatical removal of an unpredictable number of mural TE cells from the human blastocyst. We observed strikingly similar obstetrical and neonatal complications in pregnancies where the placenta bears PGF downmodulation or a TE biopsy has been done. In both groups, the risk of PE, IUGR, congenital cardiac ventricular septal defects, caesarean section, sex ratio in favour of males and preterm birth is significantly increased compared to controls. Given the high degree of correlation, the observation may not be a casual one. We postulate herein that the TE biopsy may induce persistent dysregulation of different genes in the placenta including PGF. The mechanism proposed is the disruption of tight junctions caused by the TE biopsy.

Validation of preimplantation genetic tests for aneuploidy (PGT-A) with DNA from spent culture media (SCM): concordance assessment and implication

BACKGROUND

Spent culture medium (SCM) as a source of DNA for preimplantation genetic tests aneuploidy (PGT-A) has been widely discussed.

METHODS

Seventy-five blastocysts that were donated for research provided a unique possibility in which multiple specimens, including trophectoderm (TE) biopsy, SCM, and paired corresponding whole blastocyst (WB) specimens from the same blastocyst source, could be utilized for the purpose of this preclinical validation.

RESULTS

To conduct a validation ploidy concordance assessment, we evaluated the full chromosomal concordance rates between SCM and WB (SCM-to-WB), and between TE and WB (TE-to-WB) as well as sensitivity, specificity and overall diagnostic accuracy. 78.67% (59/75) of NGS results in the SCM group were interpretable, a significantly lower percentage than their corresponding TE and WB groups. This discrepancy manifests itself in intrinsically low quantity and poor integrity DNA from SCM. Subsequently, remarkable differences in full concordance rates (including mosaicism, and segmental aneuploidies) are seen as follows: 32.2% (SCM-to-WB, 19/59) and 69.33% (TE-to-WB, 52/75), (p < 0.001). In such cases, full concordance rates were 27.27% (15/55) in SCM-to-WB, and, 76% (57/75) in TE-to-WB (p < 0.001). Collectively, the NGS data from SCM also translated into lower sensitivities, Positive Predictive Value (PPV), Negative Predictive Value (NPV), overall diagnostic accuracies, and higher Negative Likelihood Ratio (NLR).

CONCLUSIONS

Our study reveals that DNA is detectable in the majority of SCM samples. Individual chromosomal aberration, such as segmental aneuploidy and mosaicism, can be quantitatively and qualitatively measured. However, TE still provides a more accurate and reliable high-throughput methodology for PGT-A. Meanwhile, cell-free DNA in SCM reporting lacks uniform diagnostic interpretations. Considering that this test is meant to determine which embryos are relegated to be discarded, PGT-A with cell-free DNA in SCM should not be permitted to be applied in routine clinical settings for diagnosis purpose.

Current Advancements in Noninvasive Profiling of the Embryo Culture Media Secretome

There have been over 8 million babies born through in vitro fertilization (IVF) and this number continues to grow. There is a global trend to perform elective single embryo transfers, avoiding risks associated with multiple pregnancies. It is therefore important to understand where current research of noninvasive testing for embryos stands, and what are the most promising techniques currently used. Furthermore, it is important to identify the potential to translate research and development into clinically applicable methods that ultimately improve live birth and reduce time to pregnancy. The current focus in the field of human reproductive medicine is to develop a more rapid, quantitative, and noninvasive test. Some of the most promising fields of research for noninvasive assays comprise cell-free DNA analysis, microscopy techniques coupled with artificial intelligence (AI) and omics analysis of the spent blastocyst media. High-throughput proteomics and metabolomics technologies are valuable tools for noninvasive embryo analysis. The biggest advantages of such technology are that it can differentiate between the embryos that appear morphologically identical and has the potential to identify the ploidy status noninvasively prior to transfer in a fresh cycle or before vitrification for a later frozen embryo transfer.