Blastocyst mtDNA quantity threshold in relation to clinical outcome.

<p><b>a)</b> The mtDNA quantity viability threshold for euploid blastocysts, established via retrospective analysis of TE biopsies from transferred embryos with known outcomes. All blastocysts producing viable pregnancies contained mtDNA quantities below the 0.003 value (red line) whereas mtDNA quantities above this value were associated with failure to achieve an ongoing clinical pregnancy. <b>b)</b> Results of the prospective blinded study. The mtDNA threshold used was the same as that established in the retrospective study (4a). Validity was confirmed, since all blastocysts producing viable pregnancies contained mtDNA quantities below the cut-off (red line) and no blastocysts with mtDNA quantities above this value achieved an ongoing clinical pregnancy. <b>c)</b> NGS analysis of the mtDNA level in 23 euploid TE samples. The corresponding embryos were transferred during SET cycles, and clinical outcomes were known for 21 of them. As with the real-time PCR experiments, mtDNA levels were lower in the seven implanting embryos (note- the y-axis scale is different for NGS analyses and consequently cut-off values differ).