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The Journal "Obstetrics and Gynecology"Journal HistoryAims and ScopePolicies on Conflict of Interest, Human and Animal Rights, and Informed ConsentEditorial ProcessData sharing statementAdvertising PolicyThe Process for Handling Cases Requiring Corrections, Retractions, and Editorial Expressions of ConcernEditorial BoardEditorial CounsilInformation for ProfessionalsNewsContacts
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Obstetrics and Gynegology2025№9
Chromosomal mosaicism in human embryos:...

Chromosomal mosaicism in human embryos: a variant of normal development or pathology?

DOI
https://dx.doi.org/10.18565/aig.2025.157

Savostina G.V., Timofeeva A.V., Ekimov A.N., Perminova S.G., Nazarenko T.A.

Academician V.I. Kulakov National Medical Research Centre for Obstetrics, Gynecology and Perinatology, Ministry of Health of Russia, Moscow, Russia

Objective: To analyze the current data on chromosomal mosaicism in human embryos and the mechanisms of its formation, as well as its clinical significance in the context of assisted reproductive technologies.
Materials and methods: This is a systematic review of the literature that includes the analysis of the results of preimplantation genetic testing for aneuploidy (PGT-A), data on sequencing of individual embryo cells, and outcomes of cryocycles with mosaic embryo transfer.
Results: Modern diagnostic methods reveal a wide spectrum of chromosomal mosaicisms, depending on the technology used and the interpretation criteria. Sequencing of individual cells demonstrates a high prevalence of mosaicism in human embryos with an average proportion of aneuploid cells of 25%. Self-correction mechanisms include selective apoptosis of aneuploid cells controlled by bone morphogenetic protein (BMP4), preferential division of euploid cells, and slowing proliferation of aneuploid blastomeres. Meta-analysis of 1,106 cryocycles showed no significant differences in reproductive outcomes with mosaicism levels below 50%. Segmental chromosomal abnormalities are associated with more favorable outcomes compared to numerical anomalies. Prenatal diagnosis confirms normal fetal karyotype in 86% of cases following mosaic embryo transfer.
Conclusion: Research findings indicate insufficient diagnostic significance of single trophectoderm biopsy for assessing chromosomal status of the entire embryo. The high frequency of mosaicism and the ability of an embryo to self-correct make it possible to consider a certain level of chromosomal mosaicism as a normal variant of embryonic development. This justifies a revision of the criteria for selecting embryos for transfer, with a greater tolerance for low-level mosaicism.

Authors’ contributions: Savostina G.V. – data analysis, drafting of the manuscript; Timofeeva A.V., Ekimov A.N. – editing the manuscript, critical analysis of the article; Nazarenko T.A., Perminova S.G. – editing the text, final approval of the manuscript.
Conflicts of interest: The authors declare that there are no conflicts of interest.
Funding: The research was carried out with the financial support of the Ministry of Health of the Russian Federation within the framework of the state assignment 125022002648-0 on the subject: “Assessment of the blastocyst ploidy and its implantation potential by the level of extracellular piwiRNAs in the culture medium”.
For citation: Savostina G.V., Timofeeva A.V., Ekimov A.N., Perminova S.G., Nazarenko T.A. 
Chromosomal mosaicism in human embryos: a variant of normal development or pathology?
Akusherstvo i Ginekologiya/Obstetrics and Gynecology. 2025; (9): 30-38 (in Russian)
https://dx.doi.org/10.18565/aig.2025.157

Keywords

chromosomal mosaicism
preimplantation genetic testing
aneuploidy
assisted reproductive technologies
embryo self-correction
Full text (in Russian)

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Received 18.06.2025

Accepted 13.08.2025

About the Authors

Guzel V. Savostina, PhD, Junior Researcher, Department of Assisted Reproductive Technologies, Laboratory of Applied Transcriptomics, Department of Assisted Reproductive Technologies, Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Health of Russia, 4, Oparina str., Moscow, 117997, Russia, +7(925)633-35-16, g_savostina@oparina4.ru, https://orcid.org/0009-0006-8294-011X
Angelika V. Timofeeva, PhD, Head of the Laboratory of Applied Transcriptomics, Department of Systems Biology in Reproduction, Institute of Translational Medicine, Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Health of Russia, 4, Oparina str., Moscow, 117997, Russia, a_timofeeva@oparina4.ru, https://orcid.org/0000-0003-2324-9653
Аlexey N. Ekimov, PhD, Head of the Laboratory of Preimplantation Genetic Testing and Genetic Diagnostics, Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Health of Russia, 4, Oparina str., Moscow, 117997, Russia, a_ekimov@oparina4.ru,
https://orcid.org/0000-0001-5029-0462
Svetlana G. Perminova, Dr. Med. Sci., Professor, Department of Assisted Reproductive Technologies, Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Health of Russia, 4, Oparina str., Moscow, 117997, Russia, s_perminova@oparina4.ru,
https://orcid.org/0000-0003-4438-1354
Tatyana A. Nazarenko, Dr. Med. Sci., Professor, Head of the Department of Assisted Reproductive Technologies, Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Health of Russia, 4, Oparina str., Moscow, 117997, Russia, t_nazarenko@oparina4.ru,
https://orcid.org/0000-0002-5823-1667
Corresponding author: Guzel V. Savostina, g_savostina@oparina4.ru

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