Embryo fragmentation and its relationship with aneuploidy

Abstract

Objective: Selecting embryos is an important step in the in vitro fertilization process before transferring them to the uterus. There are some invasive methods for choosing a good quality embryo, such as embryo grading. This method evaluates the equality and fragmentation of an embryo. However, this method does not adequately evaluate the chromosomal status of the embryos, which is often necessary for high-risk embryos. Here, we evaluated embryo fragmentation and chromosomal numbers using next-generation sequencing. Materials and Methods: Each embryo was biopsied on the 3rd or 5th culture day to obtain a single blastomere cell. DNA was then extracted from each blastomere and whole-genome amplification was carried out. Amplification products were then sequenced to obtain a ploidy number. Results: Among the 30 embryos that were evaluated, 19 embryos had no fragments, 10 embryos had small fragments, and 1 embryo had moderate fragments. However, 12 of 19 embryos, 57.9% with no fragments were detected to have chromosomal abnormality. Aneuploidy was increased in 7 of 10 embryos (70%) with mild fragments. One moderately fragmented embryo included was surprisingly found to have normal ploidy (100%). Gamma correlation test showed that there was no correlation between fragmentation and the incidence rate of aneuploidy (P > 0.05). Although there was no correlation, the study's result exemplifies that aneuploidy rate increased along with higher fragmentation. Conclusion: This research concluded that embryo fragmentation was not correlated with aneuploidy.