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 ... -  《-》

The utility of human two plus one small pronucleated zygotes (2.1PN) based on clinical outcomes and the focused ploidy analysis.

Are human embryos arising from two plus one small pronucleated zygotes, called 2.1 pronuclei (PN), clinically useful? In a retrospective embryo cohort study and prospective experimental study, a total of 287 cycles in which at least one 2.1PN was identified in the fertilization check were included. Embryonic development and clinical outcome were compared for the 1395 2PN zygotes and 304 2.1PN zygotes that were siblings. All embryos were individually cultured in time-lapse systems. Twenty-five 2.1PN-derived blastocysts, donated for research, were used in focused single-nucleotide variant ploidy analysis to identify the distribution pattern of heterozygosity. The average diameter of PN was 24.9 ± 2.4 µm for large PN and 10.2 ± 2.4 µm for small PN; 79.9% of small PN was derived from female pronuclei. Blastocyst formation rate and good-quality blastocyst rate were significantly lower with 2.1PN embryos than with 2PN embryos (40.0% vs. 57.7%, 21.4% vs. 33.5%, respectively). A total of 13 embryos derived from 2.1PN were transferred, and three healthy babies were born. In ploidy constitutions of trophectoderm (TE), 2.1PN-derived blastocyst TE was shown to be mostly diploid (95.8%, 23/24), and only one blastocyst showed triploid. It was suggested that 2.1PN embryos have lower embryonic developmental potential than 2PN embryos, but most of the 2.1PN were diploid, indicating that they are likely to be clinically usable. It is recommended to perform embryo transfer following a combination of PGT-A and ploidy analysis.

Hattori H ，Okuyama N ，Ashikawa K ，Sakuraba Y ，Igarashi H ，Kyono K ... -  《-》

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 ... -  《-》

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 ... -  《-》

Effect of the male factor on the clinical outcome of intracytoplasmic sperm injection combined with preimplantation aneuploidy testing: observational longitudinal cohort study of 1,219 consecutive cycles.

To evaluate the impact of the male factor on the outcomes of intracytoplasmic sperm injection (ICSI) cycles combined with preimplantation genetic testing for aneuploidies (PGT-A). Observational longitudinal cohort study. Private in vitro fertilization (IVF) center. A total of 1,219 oocyte retrievals divided into five study groups according to sperm parameters: normozoospermia (N), moderate male factor (MMF), severe oligoasthenoteratozoospermia (OAT-S), obstructive azoospermia (OA), and nonobstructive azoospermia (NOA). ICSI with ejaculated/surgically retrieved sperm, blastocyst culture, trophectoderm-based quantitative polymerase chain reaction PGT-A, and frozen-warmed euploid embryo transfer (ET). The primary outcome measures were fertilization, blastocyst development, and euploidy rates; the secondary outcome measures were live birth and miscarriage rates. Perinatal and obstetrical outcomes were monitored as well. A total of 9,042 metaphase II oocytes were inseminated. The fertilization rate was significantly reduced in MMF, OAT-S, OA, and NOA compared with N (74.8%, 68.7%, 67.3%, and 53.1% vs. 77.2%). The blastocyst rate per fertilized oocyte was significantly reduced in MMF and NOA compared with N (48.6% and 40.6% vs. 49.3%). The timing of blastocyst development also was affected in OA and NOA. Logistic regression analysis adjusted for confounders highlighted NOA as a negative predictor of obtaining an euploid blastocyst per OPU (odds ratio 0.5). When the analysis was performed per obtained blastocyst, however, no correlation between male factor and euploidy rate was observed. Embryo transfers also resulted in similar live birth and miscarriage rates. No impact of sperm factor on obstetrical/perinatal outcomes was observed. Severe male factor impairs early embryonic competence in terms of fertilization rate and developmental potential. However, the euploidy rate and implantation potential of the obtained blastocysts are independent from sperm quality.

Mazzilli R ，Cimadomo D ，Vaiarelli A ，Capalbo A ，Dovere L ，Alviggi E ，Dusi L ，Foresta C ，Lombardo F ，Lenzi A ，Tournaye H ，Alviggi C ，Rienzi L ，Ubaldi FM ... -  《-》