Abstracts of the 24th Annual Congress of the SBRA, 2020 (Virtual Meeting).

Abstract

Objective:Human embryos are affected by a high rate of aneuploidy, around 35% in natural conceptions and this prevalence is expected to be higher in pre-implantation embryos derived from in vitro fertilization (IVF). One of the most common alteration is the trisomy and preimplantation genetic testing for aneuploidies (PGT-A) is currently used in IVF to minimize the chances of transferring genetically abnormal embryos. The introduction of time-lapse monitoring (TLM) allowed additional noninvasive criteria to best embryo selection. Markers of embryonic kinetic from the first-cleavage onwards has been studied and applied in algorithms for best embryo choice. The aim of this study was to analyze the association of trisomy with the embryo morphokinetics in embryos derived from IVF and analyzed by PGT-A.Methods:This retrospective study included 509 embryos from 109 patients undergoing IVF between April/2018-September/2019. Mature oocytes were fertilized by ICSI and cultured in a TLM system (Embryoscope®). Blastocysts were biopsied for PGT-A and analyzed at Igenomix Brasil through Next Generation Sequencing (NGS). Twenty-seven embryos presenting trisomy of chromosomes 13, 15, 16, 18, 21 and 22 were selected and a matched analysis was performed, since a euploid embryo from the same patient was selected as a control for each trisomic embryo.Results:The women age was 38.0±3.0 years and euploid blastocyst rate was 36.3%. Two-way repeated measured ANOVA was performed based on times for achieving pronucleous-fade, two-cells, three-cells, four-cells, five-cells, eight-cells, nine-cells and blastocyst. Embryo morphokinetics significantly differed between euploid and trisomic embryos (p=0.052). The pairwise comparisons demonstrated significant difference on times between euploid and trisomic embryos from eight cells until blastocyst stage. The mean difference time between euploid and trisomic embryos to get the eight-cells stage was 5.1 hours (61.0±10.8x55.9±7.1, p=0.033) and to attain blastocyst stage was 6.2 hours (112.3±11.7x106.1±10.4, p=0.013).Conclusion:In this study, trisomic embryos showed a faster development than their paired euploid ones. Despite of this study have included a small number of embryos, the inclusion criteria was for each trisomic embryo there is an euploid embryo of the same patient, which exclude a number of confounders. The literature describes the association of accelerated embryonic development with lower success potential; however, the reason for that relationship is not clear. Our findings allow us to hypothesize that the decreased implantation potential of faster embryos could be due to chromosomal alteration, specifically trisomy, and to suggest that accelerated embryonic development may be an indication for genetic evaluation. These findings must be confirmed in a higher number of embryos and further studies are being conducted to investigate the association of genetic embryo alterations and embryo development.