ABSTRACT
The success of assisted reproduction treatments is based on the selection of the best embryos for transfer, those with the highest implantation potential and ongoing pregnancy rates: euploids.
The most reliable method to assess the chromosomal status of preimplantation embryos is preimplantation genetic testing for aneuploidies (PGT-A). Other options such as morphology and morphokinetics are not good candidates to replace PGT-A techniques, as their correlation with embryo ploidy is weak. However, biopsy-based approaches on PGT-A entail both technical and economic challenges, as embryo manipulation is needed and it could affect viability.
To avoid those limitations, noninvasive methods based on the analysis of the cell-free DNA released by the embryo during the latest stages of preimplantation development has been proposed. However, amplification and concordance rates with trophectoderm biopsies have been quite variable, pointing out the need to conduct more studies.
These studies should focus on determining the best culture conditions which are directly correlated with the quantity and quality of the DNA and the development of adapted next-generation sequencing protocols to improve detection and accuracy. This would allow noninvasive approaches to be considered as a real alternative to current PGT-A techniques.
