Levels of trophectoderm mitochondrial DNA do not predict the reproductive potential of sibling embryos.

Study question: What is the predictive value of trophectoderm mitochondrial DNA (mtDNA) quantity for blastocyst reproductive potential? Summary answer: This study demonstrates that, within a given cohort, mtDNA quantitation does not distinguish between embryos that implant and embryos that do not implant after double embryo transfer (DET). What is already known: An association between implantation failure and increased quantities of mtDNA has been observed in two studies but not in a third. Study design, size and duration: A total of 187 patients (nine who received donor oocytes) with DET of one male and one female euploid blastocyst were included in this retrospective study, with 69 singleton deliveries providing the primary dataset to evaluate the predictive value of mtDNA for reproductive potential between January 2010 and July 2016. Participants/materials, setting and method: MtDNA was quantified in cell lines to validate the quantitative PCR assay on limited quantities of starting material and then applied to 374 blastocyst biopsies. Pregnancies resulting in a singleton outcome were analyzed and newborn gender was utilized as a means to identify the implanted embryo. MtDNA quantity was then compared between implanted and non-implanted embryos in order to define the predictive value of mtDNA content for reproductive potential in this subset of patients. Main results and the role of chance: An initial comparison of mtDNA levels between all successful and unsuccessful embryos revealed no significant differences. In order to control for patient-specific variables, gender was subsequently used to identify the implanted embryo in DETs resulting in a singleton (n = 69). No systematic difference in relative mtDNA quantity was detected between implanted and non-implanted embryos. Limitations, reasons for caution: This study was conducted at a single center and did not evaluate the entire cohort of embryos from each patient to evaluate cohort specific variation in mtDNA quantity. Although the largest of its kind so far, the sample size of DETs leading to a singleton was relatively small. Wider implications of the findings: These data highlight the importance of control over patient-specific variables when evaluating candidate biomarkers of reproductive potential. All current available data suggest that mtDNA quantification needs further study before its clinical use to augment embryo selection. Study funding/competing interests: The authors have no potential conflict of interest to declare. No external funding was obtained for this study. Trial registration number: Not applicable.

SNP array-based analyses of unbalanced embryos as a reference to distinguish between balanced translocation carrier and normal blastocysts.

PURPOSE: The purpose of the study is to validate a method that provides the opportunity to distinguish a balanced translocation carrier embryo from a truly normal embryo in parallel with comprehensive chromosome screening (CCS). METHODS: A series of translocation carrier couples that underwent IVF with single nucleotide polymorphism (SNP) array-based CCS on 148 embryos were included. Predictions of balanced or normal status of each embryo were made based upon embryonic SNP genotypes. In one case, microdeletion status was used to designate whether embryos were balanced or normal. In 10 additional cases, conventional karyotyping was performed on newborns in order to establish the true genetic status (balanced or normal) of the original transferred embryo. Finally, implantation potential of balanced or normal embryos was compared. RESULTS: Phasing SNPs using unbalanced embryos allowed accurate prediction of whether transferred embryos were balanced translocation carriers or truly normal in all cases completed to date (100 % concordance with conventional karyotyping of newborns). No difference in implantation potential of balanced or normal embryos was observed. CONCLUSIONS: This study demonstrates the validity of a CCS method capable of distinguishing normal from balanced translocation carrier embryos. The only prerequisite is the availability of parental DNA and an unbalanced IVF embryo, making the method applicable to the majority of carrier couples. In addition, the SNP array platform allows simultaneous CCS for aneuploidy with the same platform and from the same biopsy. Future work will involve prospective predictions to select normal embryos with subsequent karyotyping of the resulting newborns.