Preimplantation aneuploid embryos undergo self-correction in correlation with their developmental potential

Area of Science:

• Embryology
• Reproductive Medicine
• Genetics

Background:

• Preimplantation genetic screening (PGS) is used to assess embryo chromosomal health.
• Embryo aneuploidy and mosaicism are significant factors in implantation failure and miscarriage.
• The capacity for embryonic self-correction remains an area of active research.

Purpose of the Study:

• To investigate the incidence of embryonic self-correction during preimplantation development.
• To correlate self-correction with embryo developmental stage and specific chromosomal abnormalities.
• To evaluate the implications of self-correction for PGS interpretation.

Main Methods:

• Prospective study analyzing 83 aneuploid embryos from day 3 to day 5.
• Fluorescence in situ hybridization (FISH) reanalysis was performed.
• Embryo chromosomal status was compared between day 3 and day 5, correlated with developmental stage.

Main Results:

• 18.1% of day 3 aneuploid embryos showed mosaicism.
• 32.6% of embryos exhibited partial or complete chromosomal correction by day 5.
• 9.7% of aneuploid embryos fully self-corrected; trisomic embryos showed higher correction rates (41.0% trisomic rescue).
• Self-correction was significantly higher in embryos developing to blastocyst stage (38.1%) compared to cleaved embryos (12.5%).

Conclusions:

• Embryonic self-correction of aneuploidy and mosaicism is a significant developmental process, particularly towards the blastocyst stage.
• Trisomic embryos demonstrate a greater capacity for self-correction than other aneuploidies.
• These findings necessitate cautious interpretation of preimplantation genetic screening (PGS) results.