Mitochondrial DNA Measurement

A NEW CRITERION FOR INCREASING PREGNANCY SUCCESS FOR EMBRYO SELECTION

Mitochondrial DNA contains information about the metabolism of the cell and energy production and plays an important role in the development and quality of the embryo. The fact that the repair mechanism of mitochondrial DNA is weak, that it is easily affected by aging and other factors, also has a direct impact on embryo development and pregnancy success. An important result, which studies in this regard pointed out, is that "the increase in the amount of mitochondrial DNA of the embryo harms the pregnancy success and baby birth". On the other hand, it has been revealed that changes in the mitochondrial DNA of the embryos are associated with increases in chromosomal disorders of the embryo. The researches have revealed the relationship between embryo quality/pregnancy success and mitochondrial DNA in the framework of the following conclusions:

• The increase in the amount of mitochondrial DNA negatively affects the potential for implantation (embryo's adherence to the mother's uterus), so the selection of embryos that its amount of mitochondrial DNA did not increase raises the pregnancy success.
• It was found that the amount of mitochondrial DNA in the embryos in older women is higher than in younger embryos. Thus, the negative consequences caused by advanced maternal age (mitochondrial stress) lead to an increase in the amount of mitochondrial DNA in the embryos.
• Studies also have shown that the amount of mitochondrial DNA is high in embryos with chromosomal disorders (aneuploidy).
• It has been revealed that in cases in which mitochondrial DNA has exceeded a certain threshold value the rate of pregnancy has been relatively reduced and pregnancies have terminated with early miscarriage. (A DiezJuan, F&S,2015, ElpidaFragouli, PLOS Genetics, 2015)

Based on all these results, measuring mitochondrial DNA in embryos during IVF (test tube baby) treatment is an important criterion in the selection of embryo.

Embryo analysis that we did by using NGS (New Generation Sequencing) method provides us controlling the chromosomal status of the embryo and measuring the amount of mitochondrial DNA. The measurement of the amount of mitochondrial DNA, which has contributed significantly to the success of IVF, is performed in our laboratory by using the NGS method.

Thanks to the NGS method, since we can test both the chromosomal status and the number of mitochondria of each embryo simultaneously, we can reach a good result in a short time, reliably, within the same analysis platform.

The biopsy (3rd or 5th-day biopsies) material, required for chromosome analysis (aneuploidy scan) in the embryo, is used in this test simultaneously, so there is no need for a second embryo intervention.