Embryo mosaicism in in vitro fertilization programs: from diagnostic dilemma to clinical decision (literature review)

Introduction. The introduction of preimplantation genetic testing for aneuploidies (PGT-A) into in vitro fertilization (IVF) programs has improved the effectiveness of infertility treatment. However, with the advent of next-generation sequencing (NGS) technologies, clinicians are faced with the problem of embryo chromosomal mosaicism. The feasibility of their use remains controversial and requires an analysis of the accumulated literature.
Objective. Based on an analysis of current literature, this paper presents up-to-date information on the biology of embryo chromosomal mosaicism, the clinical outcomes of mosaic embryo transfer in IVF programs, and practical algorithms for managing this category of patients.
Materials and Methods. A systematic search of scientific publications for the period from 2015 to 2026 was conducted. The review includes original studies, systematic reviews, meta-analyses, and recommendations from professional societies dedicated to embryo chromosomal mosaicism.
Results. The detection rate of mosaicism in PGT-A averages 15–25% and depends on the sensitivity of the diagnostic method, the patient’s age, and the testing protocols. According to current data, low-mosaicity MEs (less than 50%) demonstrate live birth rates comparable to euploid embryos (EEs). Embryo morphological quality is a stronger predictor of transfer success than mosaicism status. ME transfer is associated with a higher risk of miscarriage; however, in the vast majority of cases with ongoing pregnancy, the fetal karyotype is normal.
Conclusion. MEs have real reproductive potential. In the absence of EE, ME transfer is a clinically justified strategy, especially for older patients. Informed patient consent and invasive prenatal testing upon pregnancy to verify the fetal karyotype are mandatory.

1. Viotti M., Greco E., Grifo J.A., Madjunkov M., Librach C., Cetinkaya M. et al. Chromosomal, gestational, and neonatal outcomes of embryos classified as a mosaic by preimplantation genetic testing for aneuploidy. Fertil Steril 2023;120:957–66. https://doi.org/10.1016/j.fertnstert.2023.07.022

2. .Makaro­ va N.P., Ekimov A.N., Kulakova E.V., Drapkina Yu.S., Sysoeva A.P., Krasnova N.A. et al. Features of mosaicism in human embryos in infertility treatment programs using assisted reproductive technologies. Obstetrics and Gynecology. 2021;(7):144–151. (in Russian). https://doi.org/10.18565/aig.2021.7.144-151

3. Baranovskaya E.I., Voronetsky A.N. Aneuploidy and mosaicism: medical and social significance and improvement of diagnostics. Akusherstvo i ginekologiya. 2025;(3):37–43. (in Russian). https://doi.org/10.18565/aig.2025.27.

4. Kudryavtseva E.V., Fedenev S.N., Kanivets I.V., Troits­ kaya A.N., Kovalev V.V. Miscarriages after Natural Conception & IVF: Comparative Study of Genetic Analysis of Products of Conception. OBM Genet 2024;08:1– 16. https://doi.org/10.21926/obm.genet.2403255

5. Syrkasheva A.G., Sofronova Ya.V., Troshina M.N., Dobrovolskaya D.A. Embryonic mosaicism in clinical practice: interpretation of PGT-A results and patient management tactics (review). Meditsinskaya genetika. 2026;25(2):17–23. (in Russian). https://doi.org/10.25557/2073-7998.2026.02.17-23.

6. Sukhikh G.T., Trofimov D. Yu., Shubina E., Degtyarev E.N., Maslennikov D.N., Mukosey I.S. et al. Methodological recommendations «Application of high-throughput sequencing and molecular karyotyping on microarrays in the prenatal period». Akusherstvo i ginekologiya. 2024;(5):25–43. (in Russian). https://doi.org/10.18565/aig.2024.52.

7. 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. 2025;(9):30–38. (in Russian). https://doi.org/10.18565/aig.2025.157.

8. Armstrong A., Kroener L., Miller J., Nguyen A., Kwan L., Quinn M. The nature of embryonic mosaicism across female age spectrum: an analysis of 21,345 preimplantation genetic testing for aneuploidy cycles. F&S Reports 2023;4:256–61. https://doi.org/10.1016/j.xfre.2023.03.008

9. Greco E., Litwicka K., Minasi M.G., Cursio E., Greco P.F., Barillari P. Preimplantation Genetic Testing: Where We Are Today. Int J Mol Sci 2020;21. https://doi.org/10.3390/ijms21124381

10. Lysenko D.D., Trishkin A.G., Ilyin A.S., Zotova O.A., Shmelev A.A. Genetic profile of embryos in assisted reproductive technology programs in Kuzbass (Kemerovo) based on preimplantation genetic testing results. Meditsinskiy vestnik yuga Rossii. 2025;16(3):30–37. (in Russian). https://doi.org/10.21886/2219-8075-2025-16-3-30-37.

11. Greco E., Minasi M.G., Fiorentino F.. Healthy Babies after Intrauterine Transfer of Mosaic Aneuploid Blastocysts. N Engl J Med 2015;373:2089–90. https://doi.org/10.1056/NEJMc1500421

12. Capalbo A., Poli M., Rienzi L., Girardi L., Patassini C., Fabiani M. et al. Mosaic human preimplantation embryos and their developmental potential in a prospective, nonselection clinical trial. Am J Hum Genet 2021;108:2238– 47. https://doi.org/10.1016/j.ajhg.2021.11.002

13. De Rycke M., Capalbo A., Coonen E., Coticchio G., Fiorentino F., Goossens V. et al. ESHRE survey results and good practice recommendations on managing chromosomal mosaicism. Hum Reprod Open 2022;2022:hoac044. https://doi.org/10.1093/hropen/hoac044

14. Viotti M., Victor A.R., Barnes F.L., Zouves C.G., Besser A.G., Grifo J.A. et al. Using outcome data from one thousand mosaic embryo transfers to formulate an embryo ranking system for clinical use. Fertil Steril 2021;115:1212–24. https://doi.org/10.1016/j.fertnstert.2020.11.041

15. Kovtun O.P., Kudryavtseva E.V., Ovsova O.V., Nevmerzhitskaya K.S., Koryakina O.V., Tretyakova T.B. Medical genetics: textbook. Ekaterinburg: Ural State Medical University Publishing House; 2025. 192 p. (in Russian).

16. Volodyaev I., Ivanova A., Korchivaia E., Surnov A., Pomerantseva E., Lebedev I.N. et al. The chromosomal challenge of human embryos: prevalence of aneuploidy and mosaicism. F&S Rev 2025;6:100082. https://doi.org/10.1016/j.xfnr.2024.100082

17. Zhuykov A.A., Boyarsky K.Yu., Semenenko A.E., Zhuykova S.E. Efficiency and safety of preimplantation genetic testing in women of advanced reproductive age. Modern Science: Actual Problems of Theory and Practice. Series: Natural and Technical Sciences. 2024;(9):156–164. (in Russian). https://doi.org/10.37882/2223-2966.2024.9.12.

18. Cram D., Leigh D. Updated pgdis recommendations for replacement of mosaic embryos. Reprod Biomed Online 2019;39:e11–2. https://doi.org/https://doi.org/10.1016/j.rbmo.2019.04.032

19. Doroftei B., Savuca A., Anton N., Maftei R., Cretu A.-M., Bivoleanu A.R. et al. Clinical Insights Regarding the Targeted Chromosomal Region for Mosaicism and Aneuploidy in Embryos in IVF Treatment and Literature Review. Diagnostics (Basel, Switzerland) 2025;15. https://doi.org/10.3390/diagnostics15111375

20. Preimplantation Genetic Diagnosis International Society. PGDIS Position Statement on Chromosome Mosaicism and Preimplantation Aneuploidy Testing at the Blastocyst Stage 2016. https://pgdis.org/docs/newsletter_071816.html

21. Leigh D., Cram D.S., Rechitsky S., Handyside A., Wells D., Munne S. et al. PGDIS position statement on the transfer of mosaic embryos 2021. Reprod Biomed Online 2022;45:19–25. https://doi.org/10.1016/j.rbmo.2022.03.013

22. Caroselli S., Cimadomo D., Poli M., Ubaldi F., Rienzi L., Capalbo A. O-289 Morphology should be prioritised over presumed mosaicism status in PGT-A cycles: data from a non-selection study of 2,621 embryo transfers. Hum Reprod 2023;38. https://doi.org/10.1093/humrep/dead093.353

23. Listorti I., Pirastu G., Ruberti A., Barberi M., Pristerà A., Zazzaro V et al. Time-lapse analysis of embryos classified as euploid, mosaic, and aneuploid after embryonic trophectoderm biopsy. J Assist Reprod Genet 2025; 42:125–38. https://doi.org/10.1007/s10815-024-03364-7

24. Molin E.A.D., Pires G.N., Lazzari V.M. Live birth and other reproductive outcomes of mosaic and euploid embryos: a systematic review and meta-analysis. J Assist Reprod Genet 2025;42:2469–81. https://doi.org/10.1007/s10815-025-03575-6

25. Yakovlev P., Vyatkina S., Polyakov A., Pavlova M., Volkomorov V., Yakovlev M. et al. Neonatal and clinical outcomes after transfer of a mosaic embryo identified by preimplantation genetic testing for aneuploidies. Reprod Biomed Online 2022;45:88–100. https://doi.org/10.1016/j.rbmo.2022.01.010

26. Talwar D., Shah N.N., Meseguer M., Lohar U.P., Rathore S., Aggarwal R. et al. Non-invasive PGT-A allows to detect and transfer low-level mosaic embryos without impact on live birth rate. Fertil Steril 2025;124:e332. https://doi.org/10.1016/j.fertnstert.2025.07.1038

27. Harada Y., Fukunaga E., Maeda T., Sasagawa H., Ikeda M., Shiba R. et al. Kinetic characteristics of mosaic embryos observed by time-lapse and their post-implantation outcomes: A single-center retrospective cohort study. Clin Exp Reprod Med 2026. https://doi.org/10.5653/cerm.2025.08305

28. Gleicher N., Patrizio P., Mochizuki L., Barad D.H. Previously reported and here added cases demonstrate euploid pregnancies followed by PGT-A as “mosaic” as well as “aneuploid” designated embryos. Reprod Biol Endocrinol 2023;21:25. https://doi.org/10.1186/s12958-023-01077-7

29. Khorshid A., Bavan B., Chung E.H., Lathi R.B. Mosaic embryo transfer versus additional IVF with PGT-A Cycle: a decision model comparing live birth rate and cost. J Assist Reprod Genet 2024;41:635–41. https://doi.org/10.1007/s10815-024-03027-7

30. Zhang Y.X., Chen J.J., Nabu S., Yeung Q.S.Y., Li Y., Tan J.H. et al. The Pregnancy Outcome of Mosaic Embryo Transfer: A Prospective Multicenter Study and MetaAnalysis. Genes (Basel) 2020;11:973. https://doi.org/10.3390/genes11090973

31. Kalousek D.K., Vekemans M. Confined placental mosaicism. J Med Genet 1996;33:529–33. https://doi.org/10.1136/jmg.33.7.529

32. West J.D., Everett C.A. Preimplantation chromosomal mosaics, chimaeras and confined placental mosaicism. Reprod Fertil 2022;3:R66–90. https://doi.org/10.1530/RAF-21-0095

33. Hong Y.M., Kim S.H., Park H.J., Ryu H.M., Cha D.H., Kim M.Y. et al. Prenatal Ultrasound Findings and Chromosomal Outcomes of Pregnancies with Mosaic Embryo Transfer. Diagnostics 2024;14:2795. https://doi.org/10.3390/diagnostics14242795

34. Wu X., Huang H., Chen X., Chen X., Shen Q., He D. et al.Impact of confined placental mosaicism on non-invasive prenatal testing and pregnancy outcomes. Zhonghua yi xue yi chuan xue za zhi = Chinese J Med Genet 2021;38:335–8. https://doi.org/10.3760/cma.j.cn511374-20200803-00574

35. Eggenhuizen G.M., Go A., Koster M.P.H., Baart E.B., Galjaard R.J. Confined placental mosaicism and the association with pregnancy outcome and fetal growth: a review of the literature. Hum Reprod Update 2021;27:885– 903. https://doi.org/10.1093/humupd/dmab009

36. Chen C.-P., Wu F.-T., Pan Y.-T., Lee M.-S., Wang W. Lowlevel mosaic trisomy 21 at amniocentesis and cordocentesis in a pregnancy associated with a favorable fetal outcome and perinatal progressive decrease of the trisomy 21 cell line. Taiwan J Obstet Gynecol 2024;63:927– 30. https://doi.org/10.1016/j.tjog.2024.09.013

37. Greco E., Greco P.F., Listorti I., Ronsini C., Cucinelli F., Biricik A. et al. The mosaic embryo: what it means for the doctor and the patient. Minerva Obstet Gynecol 2024;76. https://doi.org/10.23736/S2724-606X.23.05281-8

38. Kovaleva N.V., Cotter P.D. Factors affecting clinical manifestation of chromosomal imbalance in carriers of segmental autosomal mosaicism: differential impact of gender. J Appl Genet 2022;63:281–91. https://doi.org/10.1007/s13353-021-00673-w

39. Morales R., Lledó B., Ortiz J.A., Arenas L., Cascales A., Ten J. et al. Perinatal and postnatal outcomes up to the third year of life after the transfer of mosaic embryos compared with euploid embryos. Fertil Steril 2024;122:537–9. https://doi.org/10.1016/j.fertnstert.2024.04.040

40. Geng T., Zhou Q., Wang Y., Ji H., Ding K., Zheng Z. et al. Comparison of pregnancy outcomes for high morphological scoring mosaic vs. low morphological scoring euploid embryos: a retrospective cohort study. J Ovarian Res 2025;18:79. https://doi.org/10.1186/s13048-025-01665-8

41. Schlade-Bartusiak K., Strong E., Zhu O., Mackie J., Salema D., Volodarsky M. et al. Mosaic embryo transfer—first report of a live born with nonmosaic partial aneuploidy and uniparental disomy 15. F&S Reports 2022;3:192–7. https://doi.org/10.1016/j.xfre.2022.05.003