Complex mosaic blastocysts after preimplantation genetic testing: prevalence and outcomes after re-biopsy and re-vitrification. Issue 2 (August 2021)

• Record Type: Journal Article
• Authors: Zhou, Shuang; Xie, Pingyuan; Zhang, Shuoping; Hu, Liang; Luo, Keli; Gong, Fei; Lu, Guangxiu; Lin, Ge
• Is Part Of: Reproductive biomedicine online. Volume 43:Issue 2(2021)
• Page Start: 215
• Page End: 222
• Publication Date: 2021-08
• Subjects: Complex mosaic -- NGS -- PGT -- Re-biopsy; Human reproductive technology -- Periodicals; Human embryo -- Periodicals; Reproduction -- Periodicals; 616.692
• DOI: 10.1016/j.rbmo.2021.04.006
• Languages: English
• ISSNs: 1472-6483

Abstract

Abstract: Research question: What is the incidence of complex mosaic in preimplantation genetic testing (PGT) blastocysts and can it be managed in clinical practice? Design: A retrospective study of PGT cycles conducted between January 2018 and October 2019 at a single centre. Biopsies of blastocysts were collected and analysed by next-generation sequencing (NGS). Complex mosaic blastocysts were defined as those with three or more mosaic chromosomes. The cryopreserved complex mosaic blastocysts underwent a second round of biopsy, NGS analysis and vitrification. The euploid blastocysts identified by the re-biopsy were warmed again for embryo transfer. The main outcomes included the prevalence of the complex mosaic and the ongoing pregnancy rate. Results: The prevalence of the complex mosaic was 2.4% (437/17, 979). The prevalence of the complex mosaic was not associated with maternal age and morphological quality. A total of 89 complex mosaic blastocysts underwent re-biopsy and 96.6% (86/89) survived the first warming. For the re-biopsy samples, 61.6% (53/86) were euploid. The poor-quality blastocysts had higher rates of aneuploidy compared with good-quality blastocysts. The survival rate for blastocysts undergoing the second warming was 100% (18/18) and resulted in an ongoing pregnancy rate of 38.9% (7/18) as well as the birth of six healthy infants. Conclusion: Re-biopsy may rescue blastocysts with development potential for transfer and improve the cumulative pregnancy rate per stimulation cycle in patients containing complex mosaic blastocysts.