Assessment of Sex Chromosomes of Human Embryos Arising from Monopronucleus Zygotes in in vitro Fertilization and Intracytoplasmic Sperm Injection Cycles of Chinese Women

Abstract

Objectives: To examine abnormal fertilization phenomena in blastomeres of embryos generated from conventional IVF and ICSI displaying a single pronucleus at the zygote stage. Methods: 132 embryos from monopronuclear zygotes (1PN) generated from conventional IVF and ICSI were examined by FISH (fluorescent in situ hybridization) with X, Y dual color centromere probes. Results: In the embryos that were obtained from conventional IVF, the percentage of diploid, monoploid and mosaic sex chromosome were 54.35, 23.91 and 21.74%, respectively. In the embryos from 1PN zygotes derived from ICSI, the percentage of diploid, monoploid and mosaic sex chromosomes were 31.51, 31.51 and 36.99%, respectively. For monoploid embryos, the ratio of XO was significantly higher than that of YO in both conventional IVF and ICSI groups. Conclusion: The results demonstrated that the majority of embryos derived from 1PN zygotes generated with conventional IVF or ICSI have a high incidence of aneuploidy. Furthermore, the sex chromosome diploid ratio of embryos from 1PN zygotes derived from conventional IVF was significantly higher than those generated from ICSI procedure in Chinese women. Nevertheless, the high proportion of aneuploid embryos suggests that such embryos should not be utilized for embryo transfer.