Cell-free deoxyribonucleic acid analysis in preimplantation genetic testing

Abstract

Detection of chromosomal aneuploidies and monogenic disorders in preimplantation embryos is essential for selecting the best embryo for transfer during in vitro fertilization to achieve a healthy pregnancy. Preimplantation genetic testing (PGT) is typically performed on preimplantation embryos to select a genetically normal embryo for transfer. A trophectoderm biopsy is necessary for PGT; this is an invasive procedure to the embryo that requires specialized equipment and highly trained embryologists, resulting in high costs associated with in vitro fertilization treatment. Moreover, the biopsy procedure may increase the likelihood of developing pregnancy complications, such as preeclampsia and hypertensive disorders. Therefore, there is a need for noninvasive embryo screening strategies. The presence of cell-free deoxyribonucleic acid in the embryo culture medium presents an opportunity to screen for genetic abnormalities. Cell-free deoxyribonucleic acid is released by embryos in the latter stages of preimplantation development, and its analysis has been proposed as a noninvasive approach for PGT. Here, we review studies reporting the concordance rates between cell-free deoxyribonucleic acid and trophectoderm biopsies, or whole blastocysts, in couples undergoing PGT. Noninvasive PGT results are promising for aneuploidy detection, with some early evidence of successful clinical application. Further research is required to explore its application for the detection of structural rearrangements and monogenic disorders.

Keywords: PGT-A; PGT-M; PGT-SR; cell-free DNA; niPGT-A.