Embryos derived from single pronucleus are suitable for preimplantation genetic testing.

To study and compare the preimplantation genetic testing for monogenic disorders (PGT-M) results, and to evaluate the treatment cycle outcomes of embryos derived from a single pronucleus (1PN) vs. two pronuclei (2PN). A retrospective cohort study from January 2018 to December 2022 involving in vitro fertilization (IVF)-PGT-M treatment cycles. Single, academically affiliated fertility center. A total of 244 patients underwent 351 IVF-PGT-M treatment cycles. Embryo biopsy with molecular testing for a monogenic disorder. The molecular diagnosis results and clinical outcomes after the transfer of embryos derived from 1PN and 2PN in IVF-PGT-M treatment cycles. Embryos derived from 1PN have a significantly low developmental potential with a lower rate of embryos that underwent biopsy compared with 2PN-derived embryos; 1PN-derived embryos demonstrated a significantly lower number of blastocysts (24% vs. 37.9%) and top-quality blastocysts (22.3% vs. 48.1%) compared with 2PN-derived embryos. Lower successfully completed and unaffected PGT-M results were achieved in 1PN compared with 2PN-derived embryos (47.1% vs. 65.5% and 18.7% vs. 31.6%, respectively), with significantly higher abnormal molecular results (39.6% vs. 22.7%). The embryo transfer of 24 1PN-derived embryos with no affected genetic disorder resulted in 5 (20.8%) clinical pregnancies and 4 (16.7%) live births (LBs). Within the limits of fewer embryos derived from 1PN that yielded unaffected embryos suitable for transfer, the clinical pregnancy and LB rate of 1PN embryos undergoing PGT-M are reassuring. We, therefore, suggest applying PGT-M to embryos derived from 1PN embryos to improve the cumulative clinical pregnancy and LB rates.

Lebovitz O ，Noach-Hirsh M ，Taieb S ，Haas J ，Zilberberg E ，Nahum R ，Orvieto R ，Aizer A ... -  《-》

Abnormally fertilized oocytes can result in healthy live births: improved genetic technologies for preimplantation genetic testing can be used to rescue viable embryos in in vitro fertilization cycles.

To test whether abnormally fertilized oocyte (AFO)-derived blastocysts are diploid and can be rescued for clinical use. Longitudinal-cohort study from January 2015 to September 2016 involving IVF cycles with preimplantation genetic testing for aneuploidy (PGT-A). Ploidy assessment was incorporated whenever a blastocyst from a monopronuclear (1PN) or tripronuclear zygote (2PN + 1 smaller PN; 2.1 PN) was obtained. Private IVF clinics and genetics laboratories. A total of 556 women undergoing 719 PGT-A cycles. Conventional chromosome analysis was performed on trophectoderm biopsies by quantitative polymerase chain reaction. For AFO-derived blastocysts, ploidy assessment was performed on the same biopsy with the use of allele ratios for hetorozygous SNPs analyzed by means of next-generation sequencing (1:1 = diploid; 2:1 = triploid; loss of heterozygosity = haploid). Balanced-diploid 1PN- and 2.1PN-derived blastocysts were transferred in the absence of normally fertilized transferable embryos. Ploidy constitution and clinical value of AFO-derived blastocysts in IVF PGT-A cycles. Of the 5,026 metaphase II oocytes injected, 5.2% and 0.7% showed 1PN and 2.1PN, respectively. AFOs showed compromised embryo development (P<.01). Twenty-seven AFO-derived blastocysts were analyzed for ploidy constitution. The 1PN-derived blastocysts were mostly diploid (n = 9/13; 69.2%), a few were haploid (n = 3/13; 23.1%), and one was triploid (n = 1/13; 7.7%). The 2.1PN-derived blastocysts were also mostly diploid (n = 12/14; 85.7%), and the remainder were triploid. Twenty-six PGT-A cycles resulted in one or more AFO-derived blastocysts (n = 26/719; 3.6%). Overall, eight additional balanced-diploid transferable embryos were obtained from AFOs. In three cycles, the only balanced-diploid blastocyst produced was from an AFO (n = 3/719; 0.4%). Three AFO-derived live births were achieved: one from a 1PN zygote and two from 2.1PN zygotes. Enhanced PGT-A technologies incorporating reliable ploidy assessment provide an effective tool to rescue AFO-derived blastocysts for clinical use.

Capalbo A ，Treff N ，Cimadomo D ，Tao X ，Ferrero S ，Vaiarelli A ，Colamaria S ，Maggiulli R ，Orlando G ，Scarica C ，Scott R ，Ubaldi FM ，Rienzi L ... -  《-》

Evaluating the developmental potential of 2.1PN-derived embryos and associated chromosomal analysis.

Zygotes with 2.1 pronuclei (2.1PN) present with two normal-sized pronuclei, and an additional smaller pronucleus, that is approximately smaller than two thirds the size of a normal pronucleus. It remains unclear whether the additional pronucleus causes embryonic chromosome abnormalities. In the majority of cases, in vitro fertilization (IVF) clinics discarded 2.1PN zygotes. Thus, the present study aimed to evaluate the developmental potential and value of 2.1PN zygotes. 2.1PN-derived embryos from 164 patients who underwent IVF or intracytoplasmic sperm injection (ICSI) treatment between January 2021 and December 2022 were included in the present study. All embryos were monitored using a time-lapse system, and blastocyst formation was used to assess 2.1PN-derived embryo developmental potential. The blastocyst formation was quantified using generalized estimating equations, and chromosome euploidy was analyzed using next-generation sequencing (NGS). In addition, the potential association between age and occurrence of 2.1PN zygotes was determined. The present study demonstrated that numerous 2.1PN zygotes developed into blastocysts. Early cleavage patterns and embryo quality on Day 3 were the independent predictors for the blastocyst formation of 2.1PN-derived embryos. The 2.1PN zygotes displayed a comparable developmental potential compared to 2PN zygotes in advanced age patients (≥ 38). Moreover, there was a tendency that 2.1PN-derived blastocysts showed a similar euploidy rate compared to 2PN-derived blastocysts. Clinicians should consider using 2.1PN-derived euploid embryos for transfer after preimplantation genetic testing in the absence of available 2PN embryo cycles. 2.1PN-derived embryos could be a candidate, particularly beneficial for patients at advanced age.

Wang J ，Xiong S ，Hao X ，Gao Y ，Xia F ，Liao H ，Zou J ，Huang G ，Han W ... -  《-》

Genome-wide haplotyping embryos developing from 0PN and 1PN zygotes increases transferrable embryos in PGT-M.

Destouni A ，Dimitriadou E ，Masset H ，Debrock S ，Melotte C ，Van Den Bogaert K ，Zamani Esteki M ，Ding J ，Voet T ，Denayer E ，de Ravel T ，Legius E ，Meuleman C ，Peeraer K ，Vermeesch JR ... -  《-》

Clinical outcomes of frozen-thawed blastocysts from zygotes with no or one pronucleus for in vitro fertilization and intracytoplasmic sperm injection cycles.

To investigate the clinical outcomes of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles using frozen-thawed blastocyst transfers derived from zygotes with no (0PN) or one pronucleus (1PN). This retrospective study included 7084 0PN, 2238 1PN, and 72,266 two pronuclear (2PN) embryos cultured to the blastocyst stage from 19,631 IVF and 12,377 ICSI cycles between March 2018 and December 2021. Developmental potential and clinical outcomes of 0PN, 1PN, and 2PN embryos were analyzed. A total of 290 0PN-, 92 1PN-, and 1906 2PN-derived single frozen-thawed blastocyst transfers were performed. Chromosome euploid rates of 0PN-, 1PN-, and 2PN-derived blastocysts were analyzed by next-generation sequencing. Euploid 0PN- and 1PN-derived blastocysts underwent subsequent Infinium Asian Screening Array gene chip analysis to detect ploidy alterations. Available blastocyst rates of 0PN and 1PN embryos were significantly lower than those of 2PN embryos in both IVF and ICSI cycles. Single 0PN and 1PN blastocysts transferred in frozen-thawed cycles resulted in a similar clinical pregnancy rate, miscarriage rate, live birth rate, and neonatal outcome to 2PN blastocysts in IVF and ICSI cycles. Genetic analysis showed that euploid rates of 0PN- and 1PN-derived blastocysts used for ICSI cycles were similar to that of 2PN-derived blastocysts. Our study indicated that 0PN- and 1PN-derived blastocysts resulted in similar clinical outcomes to 2PN-derived blastocysts. The 0PN- and 1PN-derived blastocysts from ICSI cycles can be transferred as well as those from IVF cycles when the number of 2PN-derived blastocysts is insufficient.

Tong X ，Jin J ，Xue Y ，Fang L ，Zhu H ，Jiang L ，Zhang S ... -  《-》