Contraction behaviour reduces embryo competence in high-quality euploid blastocysts

Area of Science:

• Reproductive Science
• Embryology
• Genetics

Background:

• Preimplantation genetic testing for aneuploidies (PGT-A) is crucial for assessing embryo viability.
• Blastocyst development involves complex morphological changes, including contractions, whose significance is not fully understood.
• Understanding factors affecting reproductive competence is key to improving IVF outcomes.

Purpose of the Study:

• To investigate the relationship between blastocyst contraction behavior and reproductive competence in high-quality euploid embryos.
• To determine if embryo contractions are associated with ploidy status (euploid vs. aneuploid).
• To assess the impact of contractions on implantation and pregnancy rates.

Main Methods:

• Retrospective analysis of time-lapse monitoring (TLM) data from 896 high-quality blastocysts.
• Classification of embryos as euploid or aneuploid based on PGT-A results.
• Correlation of blastocyst contraction frequency with ploidy status and reproductive outcomes (implantation, pregnancy rates).

Main Results:

• Aneuploid blastocysts exhibited significantly more contractions than euploid blastocysts (1.57 vs. 0.6; p < 0.001).
• Monosomic embryos showed fewer contractions compared to trisomic or complex aneuploid embryos.
• Euploid embryos with contractions had lower implantation (47.6%) and clinical pregnancy rates (40.0%) compared to those without contractions (78.5% and 59.0%, respectively).

Conclusions:

• Embryo contraction is influenced by the embryo's ploidy status.
• Aneuploid embryos can achieve high morphological scores despite chromosomal abnormalities.
• The presence of blastocyst contractions may negatively impact implantation success, regardless of ploidy.