Using outcome data from one thousand mosaic embryo transfers to formulate an embryo ranking system for clinical use


      To study how the attributes of mosaicism identified during preimplantation genetic testing for aneuploidy relate to clinical outcomes, in order to formulate a ranking system of mosaic embryos for intrauterine transfer.


      Compiled analysis.




      A total of 5,561 euploid blastocysts and 1,000 mosaic blastocysts used in clinical transfers in patients undergoing fertility treatment.



      Main Outcome Measure(s)

      Implantation (gestational sac), ongoing pregnancy, birth, and spontaneous abortion (miscarriage before 20 weeks of gestation).


      The euploid group had significantly more favorable rates of implantation and ongoing pregnancy/birth (OP/B) compared with the combined mosaic group or the mosaic group affecting only whole chromosomes (implantation: 57.2% vs. 46.5% vs. 41.8%; OP/B: 52.3% vs. 37.0% vs. 31.3%), as well as lower likelihood of spontaneous abortion (8.6% vs. 20.4% vs. 25%). Whole-chromosome mosaic embryos with level (percent aneuploid cells) <50% had significantly more favorable outcomes than the ≥50% group (implantation: 44.5% vs. 30.4%; OP/B: 36.1% vs. 19.3%). Mosaic type (nature of the aneuploidy implicated in mosaicism) affected outcomes, with a significant correlation between number of affected chromosomes and unfavorable outcomes. This ranged from mosaicism involving segmental abnormalities to complex aneuploidies affecting three or more chromosomes (implantation: 51.6% vs. 30.4%; OP/B: 43.1% vs. 20.8%). Combining mosaic level, type, and embryo morphology revealed the order of subcategories regarding likelihood of positive outcome.


      This compiled analysis revealed traits of mosaicism identified with preimplantation genetic testing for aneuploidy that affected outcomes in a statistically significant manner, enabling the formulation of an evidence-based prioritization scheme for mosaic embryos in the clinic.
      Usando los resultados de transferencias de mil embriones mosaicos para la formulación de un sistema de puntuación embrionaria para uso clínico


      Estudiar cómo las características de embriones mosaicos identificadas mediante análisis genético preimplantacional para la detección de aneuploidias se relacionan con los resultados clínicos, con el objetivo de formular un sistema de puntuación de embriones mosaicos a transferir.


      Estudio compilado.

      Tipo de estudio



      Un total de 5,561 blastocistos euploides y 1,000 blastocistos mosaicos transferidos a pacientes sometidas a tratamientos de fertilidad.



      Medida(s) del resultado principal

      Implantación (saco gestacional), embarazo evolutivo, nacimiento y aborto espontáneo (pérdida gestacional antes de las 20 semanas de gestación).


      El grupo de embriones euploides tuvo tasas de implantación y tasas de embarazo evolutivo y nacimiento significativamente más favorables en comparación con el grupo de embriones mosaicos combinados y con el grupo de embriones mosaicos que tenían afectados cromosomas al completo (implantación: 57.2% vs. 46.5% vs. 41.8%; OP/B: 52.3% vs. 37.0% vs. 31.3%)), así como una menor probabilidad de aborto espontáneo (8.6% vs. 20.4% vs. 25%). Los embriones mosaicos con afectación de cromosomas completos con niveles (porcentaje de células aneuploides) < 50% presentaron resultados significativamente más favorables que el grupo con niveles ≥ 50% (implantación: 44.5% vs. 30.4%; OP/B: 36.1% vs. 19.3%). El tipo de mosaicismo (naturaleza de la aneuploidía implicada en el mosaicismo) afectó a los resultados clínicos, observándose una correlación significativa entre el número de cromosomas afectados y resultados desfavorables. Este rango de mosaicismo comprende desde anomalías segmentales hasta aneuplodías complejas con afectación de tres o más cromosomas (implantación: 51.6% vs. 30.4%; OP/B: 43.1% vs. 20.8%). La combinación del nivel de mosaicismo, el tipo y la morfología embrionaria definen un orden de subcategorías en función de la posibilidad de un resultado clínico positivo.


      Este análisis compilado reveló rasgos de mosaicismo identificados mediante testado genético preimplantacional de aneuploidías que afectaron los resultados de una manera estadísticamente significativa, permitiendo la formulación de un esquema de priorización basado en la evidencia para los embriones mosaicos en la clínica.

      Key Words

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