EFFECTS OF THE TIMING OF THE FIRST CELL DIVISION ON THE PREIMPLANTATION DEVELOPMENT OF ICSI MOUSE EMBRYOS

Abstract

It became more important than ever to be able to choose the ‘right embryo’, the one that is destined to implant. While techniques such as preimplantation genetic diagnosis, mitochondrial DNA analysis, or secreted protein evaluation have advanced preimplantation embryo assessment, they are invasive and can pose risks to the embryo. The timing of the first cleavage has recently emerged as a reliable, noninvasive marker for embryonic viability. This study examines embryonic markers of potential and quality during the preimplantation development of ICSI mouse embryos concerning the timing of the first cell division. Embryos were categorized into four groups based on their first cell division timing: 18-20 hours, 20-22 hours, 22-24 hours, and 24-28 hours post fertilization. The results indicated that embryos undergoing the first cell division at 18-20 hours showed higher efficiency in yielding blastocysts compared to those dividing at the two-cell stage (82.6% vs. 64.4%, 47.1%, and 31.3%, P<0.05). Additionally, embryos dividing at 18-20 hours had significantly higher total cell numbers compared to those at other timings (109 vs. 80, 53, and 39; P<0.05). These findings provide a simple, accurate, and noninvasive method for embryo selection, potentially improving the success rates of embryo transfer in assisted reproductive technology (ART).