1PN and 0PN zygotes, Genome-wide ploidy and haplotyping, Preimplantation genetic testing for structural rearrangements, Karyomapping, Gynecology and obstetrics, RG1-991

Abstract Background While zygotes lacking pronuclei (0PN) or exhibiting a single pronucleus (1PN) may theoretically yield diploid embryos with developmental potential, current clinical protocols predominantly exclude these embryos from use. In the population undergoing preimplantation genetic testing for structural rearrangements (PGT-SR), there is a high rate of chromosomal aneuploidy abnormalities and needs a large number of embryos to obtain euploid embryos, so we will explore whether 0PN and 1PN embryos can be an option for them. Methods This retrospective analysis examined pronuclear development in 4,868 zygotes derived from 4,902 injected metaphase II (MII) oocytes across 422 assisted reproductive cycles. In a subset of 54 cycles (12.8%), preimplantation genetic testing for structural rearrangements (PGT-SR) was implemented for blastocysts originating from 0PN and 1PN embryos that progressed to Day 5/6 development stage prior to vitrification. Comprehensive genomic haplotyping was performed on 343 embryos within this subgroup, including 33 0PN-derived, 36 1PN-derived, and 274 conventional 2PN-derived specimens. The investigation’s primary endpoint focused on neonatal survival outcomes, while secondary assessments evaluated both embryo transfer suitability and chromosomal normality rates. Results Compared to 2PN embryos, the proportion of 0PN and 1PN embryos developing into blastocysts is significantly lower (5.41%, 21.56% vs. 56.51%, p-value