A mathematical model for predicting the number of transferable blastocysts in next-generation sequencing-based preimplantation genetic testing

Systematic review and meta-analysis of the impact of the refreezing and rebiopsy embryos on reproductive outcomes in patients undergoing freeze-thaw embryo transfer

IMPORTANCE

During frozen-thawed embryo transfer (FET) cycles in in vitro fertilization/intracytoplasmic sperm injection patients (including preimplantation genetic testing patients), transfer of embryos that have been thawed may be abandoned for medical or personal reasons, resulting in the need to refreeze embryos. Typically, embryos from patients undergoing preimplantation genetic testing are cryopreserved after biopsy, pending test results. However, in the absence of a clear result, another biopsy is required, and the embryo is frozen again to await the results for future use.

OBJECTIVE

To explore whether refreezing and rebiopsy affect reproductive outcomes.

DATA SOURCES

Computer search was conducted in PubMed, Embase, Cochrane Library, Web of Science, CBM, CNKI, WanFang Data, and VIP databases and searched until May 2023.

STUDY SELECTION AND SYNTHESIS

STATA/MP software was used for conducting data analysis. Dichotomous outcome data were pooled to calculate odds ratios (ORs) and their corresponding 95% confidence intervals (CIs). Continuous outcome data were combined using an inverse variance model to determine the mean difference between the two groups. Random-effects and fixed-effects meta-analysis models were employed to assess heterogeneity. Subgroup analysis was conducted on the basis of different freezing methods and various embryo types.

MAIN OUTCOMES

The primary outcome measure was the live birth rate (LBR), with secondary indicators including clinical pregnancy rate (CPR), implantation rate, miscarriage rate (MR), ectopic pregnancy, preterm delivery, mean birth weight of neonates, and neonatal malformation.

RESULTS

This study included 19 retrospective studies with a total of 11,024 FET cycles. Across the FET cycles, recryopreservation, compared with once-cryopreservation, demonstrated reduced LBRs (OR, 0.79; 95% CI, 0.60 -0.92; I2 = 21.7%), reduced CPRs (OR, 0.74; 95% CI, 0.60 -0.92; I2 = 56.9%), and increased MRs (OR, 1.27; 95% CI, 1.03 -1.55; I2 = 37.1%). Pregnancy outcomes after rebiopsies, revealing significantly lower LBRs after rebiopsies than after single biopsy (OR, 0.65; 95% CI, 0.45 -0.94; I2 = 43.5%). Similarly, rebiopsies were associated with reduced CPRs (OR, 0.75; 95% CI, 0.54 -1.03; I2 = 29.6%) and increased MRs (OR, 1.54; 95% CI, 0.89 -2.66; I2 = 13.0%) compared with single biopsy.

CONCLUSION AND RELEVANCE

Refrozen embryos compared with once-frozen embryos suggest a decrease in the LBRs and CPRs, coupled with an increase in the MRs, with negligible influence on neonatal outcomes. Similarly, rebiopsy yields comparable results, leading to a reduction in the LBRs.

Identification of novel candidate genes associated with meiotic aneuploidy in human embryos by whole-exome sequencing

PURPOSE

To identify novel genetic variants responsible for meiotic embryonic aneuploidy.

METHODS

A prospective observational cohort study that included 29 couples who underwent trophectoderm biopsies from 127 embryos and performed whole-exome sequencing (WES) between November 2019 and March 2022. Patients were divided into two groups according to the expected embryo aneuploidy rate based on maternal age.

RESULTS

After variant filtering in the WES analysis of 58 patients/donors, five heterozygous variants were identified in female partners from the study group that had an impact on embryo aneuploidy. Additionally, a slowdown in embryo development and a decrease in the number of blastocysts available for biopsy were observed in the study group embryos.

CONCLUSION

This study has identified new candidate genes and variants not previously associated with meiotic embryo aneuploidy, but which are involved in important biological processes related to cell division and chromosome segregation. WES may be an efficient tool to identify patients with a higher-than-expected risk of embryo aneuploidy based on maternal age and allow for individualized genetic counselling prior to treatment.

A Mini-Review Regarding the Clinical Outcomes of In Vitro Fertilization (IVF) Following Pre-Implantation Genetic Testing (PGT)-Next Generation Sequencing (NGS) Approach

Background: PGT-based NGS revolutionized the field of reproductive medicine, becoming an integrated component within current assisted reproductive technology (ART) protocols. Methods: We searched the literature published in the last half a decade in four databases (PubMed/Medline, ISI Web of Knowledge, ScienceDirect, and Scopus) between 2018 and 2022. Results: A total of 1388 articles were filtered, from which 60 met, initially, the eligibility criteria, but only 42 were included (≥100 patients/couples—62,465 patients and 6628 couples in total) in the present mini-review. In total, forty-two (70.0%) reported reproductive outcomes, while eighteen (30.0%) had distinct objectives. Furthermore, n = 1, 1.66% of the studies focused on PGT, n = 1, 1.66% on pre-implantation genetic testing for monogenic disorders (PGT-M), n = 3, 5.0% on pre-implantation genetic testing for structural rearrangements (PGT-SR) and n = 55, 91.66% on pre-implantation genetic testing for aneuploidies (PGT-A). Conclusions: PGT using NGS proved to be an excellent companion that folds within the current ascending tendency among couples that require specialty care. We strongly encourage future studies to provide a systematic overview expanded at a larger scale on the role of the PGT-NGS.