1PN zygote

This study aimed to demonstrated the utilization value of 1PN embryos. The embryo development, the pronuclear characteristics, and the genetic constitutions were investigated. The blastocyst formation and good-quality blastocyst rates in 1PN zygotes were 22.94% and 16.24%, significantly lower than those of 2PN zygotes (63.25% and 50.23%, respectively, P=0.000). Compared to arrested embryos, 1PN zygotes that developed into blastocysts showed significantly larger area (752.57±131.53 vs. 653.65±116.58, P=0.000), longer diameter of pronuclear (30.10±2.90 vs. 27.28±2.83, P=0.000), and a greater number of nuclei (11.92± 4.06 vs. 7.72±3.07, P=0.000). Of the 86 tested embryos, the diploidy euploidy rate was significantly higher in good-quality blastocysts comparison with the arrested embryos (66.67% vs. 11.76%, P=0.000), which was also significantly higher in IVF-1PN blastocysts than in ICSI-1PN blastocysts (75.44% vs. 25.00%, P=0.001). However, the pronuclear characteristics were not related to the chromosomal ploidy once they formed good-quality blastocysts. In conclusion, the pronuclear characteristics in 1PN zygotes are related to their developmental potential. Those zygotes developed into blastocysts have unique pronuclear characteristics and significantly higher rate of diploidy euploidy in comparison with the arrested embryos. The 1PN blastocysts are recommed to be used after genetic testing, especially for those from IVF cycles.