Antonio Capalbo1, Nathan Treff2, Danilo Cimadomo3, Xin Tao2, Susanna Ferrero4, Alberto Vaiarelli4, Silvia Colamaria4, Roberta Maggiulli4, Giovanna Orlando4, Catello Scarica4, Richard Scott2, Filippo Maria Ubaldi5, Laura Rienzi5. 1. Genera, Centers for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy; Genetyx, Molecular Genetics Laboratory, Marostica, Italy. Electronic address: capalbo@generaroma.it. 2. Reproductive Medicine Associates of New Jersey, Basking Ridge, New Jersey. 3. Genera, Centers for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy; Dipartimento di Scienze Anatomiche, Istologiche, Medico Legali e dell'Apparato Locomotore, Università degli Studi di Roma "Sapienza," Rome, Italy. 4. Genera, Centers for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy. 5. Genera, Centers for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy; Genetyx, Molecular Genetics Laboratory, Marostica, Italy.
Abstract
OBJECTIVE: To test whether abnormally fertilized oocyte (AFO)-derived blastocysts are diploid and can be rescued for clinical use. DESIGN: 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. SETTING: Private IVF clinics and genetics laboratories. PATIENT(S): A total of 556 women undergoing 719 PGT-A cycles. INTERVENTION(S): 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. MAIN OUTCOME MEASURE(S): Ploidy constitution and clinical value of AFO-derived blastocysts in IVF PGT-A cycles. RESULT(S): 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. CONCLUSION(S): Enhanced PGT-A technologies incorporating reliable ploidy assessment provide an effective tool to rescue AFO-derived blastocysts for clinical use.
OBJECTIVE: To test whether abnormally fertilized oocyte (AFO)-derived blastocysts are diploid and can be rescued for clinical use. DESIGN: 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. SETTING: Private IVF clinics and genetics laboratories. PATIENT(S): A total of 556 women undergoing 719 PGT-A cycles. INTERVENTION(S): 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. MAIN OUTCOME MEASURE(S): Ploidy constitution and clinical value of AFO-derived blastocysts in IVF PGT-A cycles. RESULT(S): 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. CONCLUSION(S): Enhanced PGT-A technologies incorporating reliable ploidy assessment provide an effective tool to rescue AFO-derived blastocysts for clinical use.