Non-invasive preimplantation genetic testing for conventional IVF blastocysts

Non-invasive preimplantation genetic testing for aneuploidy using cell-free DNA in blastocyst culture medium

PURPOSE

This study evaluated the performance of preimplantation genetic testing for aneuploidies (PGT-A) using cell-free DNA (cfDNA) from spent culture media (SCM) of blastocyst embryos (non-invasive PGT-A; NiPGT-A) compared with conventional trophectoderm (TE) biopsy samples.

METHODS

This prospective study was conducted at IVFMD, My Duc Hospital, Vietnam, from August to December 2020, and included patients with an indication for PGT-A. The culture medium was replaced on day 3, and SCM from day 3 to the day of TE biopsy (days 5 or 6) of all biopsied blastocysts was tested using next-generation sequencing. The total concordance rate, sensitivity, and specificity of NiPGT-A versus PGT-A for detecting aneuploid embryos were calculated. Outcomes after single blastocyst transfer are also reported.

RESULTS

Forty-four couples participated; 100 paired TE PGT-A biopsies and SCM samples were evaluated. The whole-genome amplification success rate for SCM was 82%; 77 samples had clear NGS results and were further evaluated. The total concordance rate between NiPGT-A and PGT-A was 63.6%. For detecting aneuploidy, NiPGT-A had a sensitivity of 57.1%, specificity of 67.3%, positive predictive value of 50.0%, and negative predictive value of 73.3%. Of the 35 single euploidy embryo transfers, 8 had no NiPGT-A results, 21 were classified as NiPGT-A euploid, and 6 were classified as NiPGT-A aneuploid; the live birth rate was 51.4% (18/35). Four of the 6 NiPGT-A aneuploid blastocysts resulted in live births.

CONCLUSIONS

cfDNA in SCM has the potential for NiPGT-A. However, the NiPGT-A process is unreliable enough to replace traditional PGT-A using TE biopsy.

Non-Invasive Preimplantation Genetic Testing

To minimise the influence of chromosomal abnormalities during IVF treatment, embryos can be screened before transfer using preimplantation genetic testing. This typically involves an invasive trophectoderm biopsy at the blastocyst stage, where 4-8 cells are collected and analysed. However, emerging evidence indicates that, as embryos develop in vitro in culture media, they release cell-free DNA into the media, providing an alternative source of genetic material that can be accessed non-invasively. Spent blastocyst media samples that contain embryo cell-free DNA demonstrate high informativity rates and ploidy concordance when compared with the corresponding trophectoderm, inner cell mass, or whole blastocyst results. However, optimising this non-invasive approach requires several changes to embryo culture protocols, including additional embryo washes to tackle contamination and extending embryo culture time to maximise the amount of cell-free DNA released into the culture media. In this review, we discuss this novel non-invasive approach for aneuploidy detection and embryo prioritisation, as well as the current data and future prospects for utilising cell-free DNA analysis to identify structural rearrangements and single gene disorders.

The diagnostic accuracy of preimplantation genetic testing (PGT) in assessing the genetic status of embryos: a systematic review and meta-analysis

BACKGROUND

Preimplantation genetic testing (PGT) is widely used in assisted reproduction to assess the genetic status of embryos. However, increasing evidence suggests that the trophectoderm (TE) may not fully reflect the genetic status of the inner cell mass (ICM), raising controversy about the accuracy of TE biopsy. Research in recent years has focused on cell-free DNA (cfDNA) found in blastocoel fluid (BF) and spent culture medium (SCM), as these may contain genetic information from both the TE and ICM. Therefore, further research and validation are essential to determine the reliability and clinical applicability of these diagnostic methods in PGT.

METHODS

Relevant studies published between January 2000 and August 2024 were identified through PubMed and Web of Science (WOS). Risk assessment and publication bias were evaluated using QUADAS-2 and Deek's test. Diagnostic meta-analysis was performed using a bivariate model to combine sensitivity and specificity, with results visualized through forest plots and summary receiver operating characteristic (SROC) curves.

RESULTS

Out of 6,407 initially screened records, 36 studies involving 4,230 embryos were included. TE biopsy was identified as the best method for diagnosing the genetic status of embryos (sensitivity: 0.839; specificity: 0.791, AUC: 0.878), while SCM had slightly lower accuracy (sensitivity: 0.874; specificity: 0.719, AUC: 0.869). The effectiveness of BF (AUC: 0.656) was significantly lower than that of TE biopsy and SCM. Despite this, TE biopsy has not yet achieved ideal diagnostic performance. However, TE biopsies demonstrate a high level of accuracy in diagnosing PGT-SR (AUC: 0.957). Additionally, multiple TE biopsies (AUC: 0.966) or TE biopsies combined with SCM (AUC: 0.927) can enhance the diagnostic efficiency of PGT.

CONCLUSION

The findings of this study suggest that TE biopsy has yet to achieve optimal diagnostic accuracy, which may result in a significant number of missed embryo diagnoses and misdiagnoses. Our results confirm that SCM has the potential to serve as a supplementary test. Employing multiple biopsies or combining TE with SCM may enhance diagnostic efficiency and yield optimal results.

Non Invasive Preimplantation Testing for Aneuploidies in Assisted Reproduction: A SWOT Analysis

The implementation of non-invasive PGT-A offers a new strategy to genetically assess the preimplantation embryo and to enhance IVF results. The extraction of DNA from the embryo culture medium has been sufficiently demonstrated, and the ability to obtain chromosomal information as a result is particularly interesting. As morphological criteria have proven to have a weak correlation with embryo ploidy status, this technique emerges as a promising alternative for embryo selection. It also appears reasonable that avoiding biopsy may enhance further embryo development. However, there are growing concerns regarding several aspects of this technique, such as the origin of this cell free DNA, the degree of representativeness of the whole embryo, the need for extended culture or the absence of standardized protocols. Despite the published data on good prognosis couples are promising, niPGT-A is yet to be considered a substitute for trophectoderm biopsy. The current SWOT analysis aims to summarize both resolved and unresolved issues, as well as limiting aspects of niPGT-A.

Circular RNAs: novel noncoding players in male infertility

Infertility is a global problem being associated with emotional and financial burden. Recent studies have shown contribution of a group of non-coding RNAs, namely circular RNAs (circRNAs) to the etiology of some infertility conditions. CircRNA are transcribed from exons and form a circular RNA molecule, being abundant in eukaryotes. Traditionally classified as non-coding RNA, these transcripts are endogenously produced through either non-canonical back-splicing or linear splicing, typically produced from precursor messenger ribonucleic acid (pre-mRNA). While during the canonical splicing process the 3' end of the exon is joined to the 5' end of the succeeding exon to form linear mRNA, during backsplicing, the 3' end to the 5' end of the same exon is joined to make a circular molecule. circRNAs are involved in the regulation of several aspects of spermatogenesis. They appear to influence how stem germ cells grow and divide during the sperm production process. Malfunctions in circRNA activity could contribute to male infertility issues stemming from abnormalities in spermatogenesis. In the current review, we highlight the exciting potential of circRNAs as key players in the male fertility.

Current research status and clinical applications of noninvasive preimplantation genetic testing: A review

Noninvasive preimplantation genetic testing (ni-PGT) is conducted by obtaining genetic information from embryos through the analysis of free DNA released by embryos in spent embryo culture medium or blastocoel fluid. Compared to conventional preimplantation genetic testing relying on trophectoderm biopsy, ni-PGT is characterized by its noninvasiveness. It has demonstrated early advancements in the detection of embryonic chromosomal aneuploidies and the diagnosis of monogenic diseases, showcasing considerable potential for clinical application. However, there are substantial controversies in the literature concerning the reliability of ni-PGT, the source of cell-free DNA, and maternal contamination. This paper elaborates on the principles, research advancements, effectiveness, and limitations of ni-PGT to provide a basis for clinical applications.

The impact of implementing a non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) embryo culture protocol on embryo viability and clinical outcomes

STUDY QUESTION

Are modifications in the embryo culture protocol needed to perform non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) affecting clinical reproductive outcomes, including blastocyst development and pregnancy outcomes?

SUMMARY ANSWER

The implementation of an embryo culture protocol to accommodate niPGT-A has no impact on blastocyst viability or pregnancy outcomes.

WHAT IS KNOWN ALREADY

The recent identification of embryo cell-free (cf) DNA in spent blastocyst media has created the possibility of simplifying PGT-A. Concerns, however, have arisen at two levels. First, the representativeness of that cfDNA to the real ploidy status of the embryo. Second, the logistical changes that need to be implemented by the IVF laboratory when performing niPGT-A and their effect on reproductive outcomes. Concordance rates of niPGT-A to invasive PGT-A have gradually improved; however, the impact of culture protocol changes is not as well understood.

STUDY DESIGN, SIZE, DURATION

As part of a trial examining concordance rates of niPGT-A versus invasive PGT-A, the IVF clinics implemented a specific niPGT-A embryo culture protocol. Briefly, this involved initial culture of fertilized oocytes following each laboratory standard routine up to Day 4. On Day 4, embryos were washed and cultured individually in 10 μl of fresh media. On Day 6 or 7, blastocysts were then biopsied, vitrified, and media collected for the niPGT-A analysis. Six IVF clinics from the previously mentioned trial were enrolled in this analysis. In the concordance trial, Clinic A cultured all embryos (97 cycles and 355 embryos) up to Day 6 or 7, whereas in the remaining clinics (B-F) (379 cycles), nearly a quarter of all the blastocysts (231/985: 23.5%) were biopsied on Day 5, with the remaining blastocysts following the niPGT-A protocol (754/985: 76.5%). During the same period (April 2018-December 2020), the IVF clinics also performed standard invasive PGT-A, which involved culture of embryos up to Days 5, 6, or 7 when blastocysts were biopsied and vitrified.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 428 (476 cycles) patients were in the niPGT-A study group. Embryos from 1392 patients underwent the standard PGT-A culture protocol and formed the control group. Clinical information was obtained and analyzed from all the patients. Statistical comparisons were performed between the study and the control groups according to the day of biopsy.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean age, number of oocytes, fertilization rates, and number of blastocysts biopsied were not significantly different for the study and the control group. Regarding the overall pregnancy outcomes, no significant effect was observed on clinical pregnancy rate, miscarriage rate, or ongoing pregnancy rate (≥12 weeks) in the study group compared to the control group when stratified by day of biopsy.

LIMITATIONS, REASONS FOR CAUTION

The limitations are intrinsic to the retrospective nature of the study, and to the fact that the study was conducted in invasive PGT-A patients and not specifically using niPGT-A cases.

WIDER IMPLICATIONS OF THE FINDINGS

This study shows that modifying current IVF laboratory protocols to adopt niPGT-A has no impact on the number of blastocysts available for transfer and overall clinical outcomes of transferred embryos. Whether removal of the invasive biopsy step leads to further improvements in pregnancy rates awaits further studies.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Igenomix. C.R., L.N.-S., and D.V. are employees of Igenomix. D.S. was on the Scientific Advisory Board of Igenomix during the study.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT03520933).

Non-invasive preimplantation genetic testing for aneuploidy: is the promise real?

Recent advances in preimplantation genetic testing for aneuploidy (PGT-A) have significantly enhanced its application in ART, providing critical insights into embryo viability, and potentially reducing both the time spent in fertility treatments and the risk of pregnancy loss. With the integration of next-generation sequencing, PGT-A now offers greater diagnostic precision, although challenges related to segmental aneuploidies and mosaicism remain. The emergence of non-invasive PGT-A (niPGT-A), which analyzes DNA in spent embryo culture media, promises a simpler aneuploidy screening method. This mini review assesses the methodological criteria for test validation, the current landscape of PGT-A, and the potential of niPGT-A, while evaluating its advantages and potential pitfalls. It underscores the importance of a robust three-phase validation process to ensure the clinical reliability of PGT-A. Despite initial encouraging data, niPGT-A not only confronts issues of DNA amplification failure and diagnostic inaccuracies but also has yet to meet the three-prong criteria required for appropriate test validation, necessitating further research for its clinical adoption. The review underscores that niPGT-A, like traditional PGT-A, must attain the high standards of precision and reliability expected of any genetic testing platform used in clinical settings before it can be adopted into routine ART protocols.

Post-implantation analysis of genomic variations in the progeny from developing fetus to birth

The analysis of genomic variations in offspring after implantation has been infrequently studied. In this study, we aim to investigate the extent of de novo mutations in humans from developing fetus to birth. Using high-depth whole-genome sequencing, 443 parent-offspring trios were studied to compare the results of de novo mutations (DNMs) between different groups. The focus was on fetuses and newborns, with DNA samples obtained from the families' blood and the aspirated embryonic tissues subjected to deep sequencing. It was observed that the average number of total DNMs in the newborns group was 56.26 (54.17-58.35), which appeared to be lower than that the multifetal reduction group, which was 76.05 (69.70-82.40) (F = 2.42, P = 0.12). However, after adjusting for parental age and maternal pre-pregnancy body mass index (BMI), significant differences were found between the two groups. The analysis was further divided into single nucleotide variants (SNVs) and insertion/deletion of a small number of bases (indels), and it was discovered that the average number of de novo SNVs associated with the multifetal reduction group and the newborn group was 49.89 (45.59-54.20) and 51.09 (49.22-52.96), respectively. No significant differences were noted between the groups (F = 1.01, P = 0.32). However, a significant difference was observed for de novo indels, with a higher average number found in the multifetal reduction group compared to the newborn group (F = 194.17, P < 0.001). The average number of de novo indels among the multifetal reduction group and the newborn group was 26.26 (23.27-29.05) and 5.17 (4.82-5.52), respectively. To conclude, it has been observed that the quantity of de novo indels in the newborns experiences a significant decrease when compared to that in the aspirated embryonic tissues (7-9 weeks). This phenomenon is evident across all genomic regions, highlighting the adverse effects of de novo indels on the fetus and emphasizing the significance of embryonic implantation and intrauterine growth in human genetic selection mechanisms.

Preimplantation genetic testing: A narrative review

Preimplantation genetic testing (PGT) is a diagnostic procedure that has become a powerful complement to assisted reproduction techniques. PGT has numerous indications, and there is a wide range of techniques that can be used, each with advantages and limitations that should be considered before choosing the more adequate one. In this article, it is reviewed the indications for PGT, biopsy and diagnostic technologies, along with their evolution, while also broaching new emerging methods.

Agarose amplification based sequencing characterization cell-free RNA in preimplantation spent embryo medium

BACKGROUND

The cell-free RNA (cf-RNA) of spent embryo medium (SEM) has aroused a concern of academic and clinical researchers for its potential use in non-invasive embryo screening. However, comprehensive characterization of cf-RNA from SEM still presents significant technical challenges, primarily due to the limited volume of SEM. Hence, there is urgently need to a small input liquid volume and ultralow amount of cf-RNA library preparation method to unbiased cf-RNA sequencing from SEM. (75) RESULT: Here, we report a high sensitivity agarose amplification-based cf-RNA sequencing method (SEM-Acf) for human preimplantation SEM cf-RNA analysis. It is a cf-RNA sequencing library preparation method by adding agarose amplification. The agarose amplification sensitivity (0.005 pg) and efficiency (105.35 %) were increased than that of without agarose addition (0.45 pg and 96.06 %) by ∼ 90 fold and 9.29 %, respectively. Compared with SMART sequencing (SMART-seq), the correlation of gene expression was stronger in different SEM samples by using SEM-Acf. The cf-RNA number of detected and coverage uniformity of 3' end were significantly increased. The proportion of 5' end adenine, alternative splicing events and short fragments (<400 bp) were increased. It is also found that 4-mer end motifs of cf-RNA fragments was significantly differences between different embryonic stage by day3 spent cleavage medium and day5/6 spent blastocyst medium. (141) SIGNIFICANCE: This study established an efficient SEM amplification and library preparation method. Additionally, we successfully described the characterizations of SEM cf-RNA in preimplantation embryo using SEM-Acf, including expression features and fragment lengths. SEM-Acf facilitates the exploration of cf-RNA as a noninvasive embryo screening biomarker, and opens up potential clinical utilities of small input liquid volume and ultralow amount cf-RNA sequencing. (59).

Influence of the number of washings for embryos on non-invasive preimplantation chromosome screening results

Objective

To explore the effect of varying numbers of embryo washings prior to blastocyst formation in non-invasive preimplantation chromosome screening (NICS) on the accuracy of NICS results.

Methods

In this study, 68 blastocysts from preimplantation genetic testing (PGT)-assisted pregnancy were collected at our institution. On the fourth day of embryo culture, the embryos were transferred to a new medium for blastocyst culture and were washed either three times (NICS1 group) or ten times (NICS2 group). A trophectoderm (TE) biopsy was performed on the blastocysts, and the corresponding embryo culture media were collected for whole genome amplification (WGA) and high-throughput sequencing.

Results

The success rate of WGA was 100% (TE biopsy), 76.7% (NICS1 group), and 89.5% (NICS2 group). The success rate of WGA in embryo medium on days 5 and 6 of culture was 75.0% (33/44) and 100% (24/24), respectively. Using TE as the gold standard, the karyotype concordance rate between the results of the NICS1 and NICS2 groups' embryo culture medium samples and TE results was 43.5% (10/23) and 73.5% (25/34), respectively. The sensitivity and specificity of detecting chromosomal abnormalities were higher in the NICS2 group than in the NICS1 group when TE was used (83.3% vs 60.0%; 62.5% vs 30.8%, respectively). The false-positive rate and false-negative rate (i.e., misdiagnosis rate and missed diagnosis rate, respectively) were lower in the NICS2 group than in the NICS1 group (37.5% vs 69.2%; 16.7% vs 40.0%, respectively).

Conclusion

The NICS yielded favorable results after ten washings of the embryos. These findings provide a novel method for lowering the amount of cell-free DNA contamination from non-embryonic sources in the medium used for embryo development, optimizing the sampling procedure and improving the accuracy of the NICS test.

Advancements and Applications of Preimplantation Genetic Testing in In Vitro Fertilization: A Comprehensive Review

Preimplantation genetic testing (PGT) has become an integral component of assisted reproductive technology (ART), offering couples the opportunity to screen embryos for genetic abnormalities before implantation during in vitro fertilization (IVF). This comprehensive review explores the advancements and applications of PGT in IVF, covering its various types, technological developments, clinical applications, efficacy, challenges, regulatory aspects, and future directions. The evolution of PGT techniques, including next-generation sequencing (NGS) and comparative genomic hybridization (CGH), has significantly enhanced the accuracy and reliability of genetic testing in embryos. PGT holds profound implications for the future of ART by improving IVF success rates, reducing the incidence of genetic disorders, and mitigating the emotional and financial burdens associated with failed pregnancies and genetic diseases. Recommendations for clinicians, researchers, and policymakers include staying updated on the latest PGT techniques and guidelines, exploring innovative technologies, establishing clear regulatory frameworks, and fostering collaboration to maximize the potential benefits of PGT in assisted reproduction. Overall, this review provides valuable insights into the current state of PGT and its implications for the field of reproductive medicine.

Optimizing non-invasive preimplantation genetic testing: investigating culture conditions, sample collection, and IVF treatment for improved non-invasive PGT-A results

PURPOSE

This study aimed to optimize the non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) in the laboratory by comparing two collection timing of the spent culture medium (SCM), two embryo rinsing protocols, and the use of conventional insemination instead of intracytoplasmic sperm injection (ICSI).

METHODS

Results of two embryo rinsing methods (one-step vs sequential) and SCM collected on day 5 vs day 6 after retrieval were compared against trophectoderm (TE) biopsies as reference. Results from day 6 SCM in cycles fertilized by conventional insemination were compared with PGT-A using ICSI.

RESULTS

The rate of concordance was higher in day 6 samples than in day 5 samples when the sequential method was used, in terms of total concordance (TC; day 6 vs day 5: 85.0% vs 60.0%, p = 0.0228), total concordance with same sex (TCS, 82.5% vs 28,0%, p < 0.0001), and full concordance with same sex (FCS, 62.5% vs 24.0%, p = 0.0025). The sequential method significantly out-performed the one-step method when SCM were collected on day 6 (sequential vs one-step, TC: 85.0% vs 64.5%, p = 0.0449; TCS: 82.5% vs 54.8%, p = 0.0113; FCS: 62.5% vs 25.8%, p = 0.0021). There was no significant difference in niPGT-A results between cycles fertilized by the conventional insemination and ICSI.

CONCLUSION

We have shown a higher concordance rate when SCM was collected on day 6 and the embryos were rinsed in a sequential manner. Comparable results of niPGT-A when oocytes were fertilized by conventional insemination or ICSI. These optimization steps are important prior to commencement of a randomized trial in niPGT-A.

Conditions for improved accuracy of noninvasive preimplantation genetic testing for aneuploidy: Focusing on the zona pellucida and early blastocysts

Purpose

Recently, noninvasive preimplantation genetic testing for aneuploidy (niPGT-A) using cell-free deoxyribonucleic acid has been developed; however, there are few reports on this and the results are inconsistent. This study was conducted to optimize the cultural environment.

Methods

We used 35 blastocysts that had been discarded after in-vitro fertilization. The concordance rate of karyotype analysis results between whole embryos (WEs), spent culture mediums (SCMs), and trophectoderms after 8, 16, and 24 h of culture was examined. Next, zona pellucida (ZP)-free blastocysts and then early blastocysts were cultured for 24 h each.

Results

Regarding the optimal culture times, the concordance rate between WEs and SCMs was 20%, 60%, and 100% at 8, 16, and 24 h, respectively. Significant differences were found between 8 and 24 h. The concordance rate with ZP cultures was 40.0%, and no significant differences were found. The concordance rate of early blastocysts thawed and cultured for 24 h was 40.0%, which was significantly lower than that of day 5 blastocysts.

Conclusions

The optimal culture times for niPGT-A were 24 h, and the concordance rate with free ZP was higher. The concordance rate for early blastocysts was low, suggesting that optimization of the conditions may be necessary.

Noninvasive preimplantation genetic testing using the embryo spent culture medium: an update

PURPOSE OF REVIEW

The presence of cell-free DNA (cf-DNA) in the embryo spent culture medium allows to develop a noninvasive PGT-A (niPGTA). Noninvasive PGT-A may provide a simpler, safer and less costly approach to preimplantation genetic testing of aneuploidy (PGT-A). Furthermore, niPGTA would provide wider access to embryo genetic analysis and circumvent many legal and ethical considerations. However, the concordance rate between the results obtained by PGT-A and niPGTA varies among studies and, their clinical utility has not been already demonstrated. This review evaluates the niPGTA reliability based on SCM and adds new knowledge about the clinical relevance of SCM for noninvasive PGT-A.

RECENT FINDINGS

The most recent concordance studies evaluating the accuracy of niPGTA using SCM showed a high variation in the informativity rate of SCM and the diagnostic concordance. Also, sensitivity and specificity showed similar heterogeneous results. Therefore, these results do not support the clinical utility of niPGTA. Regarding clinical outcome, the data are initial and further research, including randomized and nonselection studies are needed.

SUMMARY

Further research, including randomized and nonselection studies, as well as optimization of embryo culture conditions and medium retrieval, are needed to improve the reliability and clinical utility of niPGTA.

Evaluation of non-invasive gene detection in preimplantation embryos: a systematic review and meta-analysis

BACKGROUND

Genetic abnormalities in embryos are responsible for most miscarriages and repeated embryo implantation failures, so a reliable preimplantation genetic screening method is urgently needed. Non-invasive preimplantation genetic testing (niPGT) is a potential method for embryo genetic diagnosis. However, the value of its application is controversial. This meta-analysis aimed to investigate and validate the diagnostic value of niPGT in patients undergoing in vitro fertilization (IVF).

METHODS

This review used the "Preferred Reporting Items" as a systematic review and meta-analysis of the diagnostic test accuracy (PRISMA-DTA) statement. We searched PubMed, Embase, Web of Science Core Collection, and Cochrane Library up to May 2022 to retrieve non-invasive preimplantation gene detection studies. The eligible research quality was evaluated following the quality assessment study-2 system for diagnostic accuracy. The pooled receiver operator characteristic curve (SROC) and the area under SROC (AUC) were used to evaluate diagnostic performance quantitatively. Threshold effect, subgroup analysis, and meta-regression analysis were used to explore the source of heterogeneity. Deeks' funnel plots and sensitivity analyses were used to test the publication bias and stability of the meta-analysis, respectively.

FINDINGS

Twenty studies met the inclusion criteria. The pooled sensitivity, specificity, and AUC were 0.84 (95% CI 0.72-0.91), 0.85 (95% CI 0.74-0.92), and 0.91 (95% CI 0.88-0.93), respectively. Subgroup analysis showed that the spent culture medium (SCM) subgroup had higher sensitivity and lower specificity than the SCM combined with the blastocoel fluid (BF) subgroup. Subgroup analysis showed that the study sensitivity and specificity of < 100 cases were higher than those of ≥ 100. Heterogeneity (chi-square) analysis revealed that sample size might be a potential source of heterogeneity. Sensitivity analysis and Deeks' funnel plots indicated that our results were relatively robust and free from publication bias.

INTERPRETATION

The present meta-analysis indicated that the pooled sensitivity, specificity, and AUC of niPGT in preimplantation genetic testing were 0.84, 0.85, and 0.91, respectively. niPGT may have high detection accuracy and may serve as an alternative model for embryonic analysis. Additionally, by subgroup analysis, we found that BF did not improve the accuracy of niPGT in embryos. In the future, large-scale studies are needed to determine the detection value of niPGT.

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.

Application of conventional IVF during preimplantation genetic testing for aneuploidies: a feasibility study

RESEARCH QUESTION

Is it feasible to apply conventional IVF to couples undergoing preimplantation genetic testing for aneuploidies (PGT-A) with non-severe male infertility?

DESIGN

The last wash fluid of biopsied trophectoderm (TE) cells was collected for whole genome amplification (WGA). A method was developed to determine parental contamination. Using single-nucleotide polymorphism (SNP) analysis, two standard curves were established; further mixtures were used for verification. Finally, 29 WGA products from couples undergoing conventional IVF were used to evaluate parental contamination.

RESULTS

The WGA results of the last wash fluid of biopsied TE cells revealed almost no free DNA. By adopting two strategies based on maternally and paternally biased SNP in the mixture, data from bioinformatics analysis were analysed to determine the relationship between maternal (Index M) and paternal (Index F) bias statistics. Two standard curves were successfully established based on these indices that allowed the prediction of maternal and parental contamination, which correlated well with actual ratios of known composition mixtures during validation. The average contamination level was 10.6% determined from 10 WGA products that featured maternal contamination, whereas that of the other 19 products that featured paternal contamination was less than 10%.

CONCLUSIONS

This study confirmed the feasibility of applying conventional IVF to couples undergoing PGT-A with non-severe male infertility.