Type of chromosome abnormality affects embryo morphology dynamics

Area of Science:

• Reproductive Medicine
• Genetics
• Embryology

Background:

• Preimplantation genetic screening (PGS) is crucial for in vitro fertilization (IVF) success.
• Embryo chromosomal abnormalities, or aneuploidy, are a major cause of implantation failure and miscarriage.
• Time-lapse technology offers detailed insights into embryo development kinetics.

Purpose of the Study:

• To investigate differences in embryo cleavage timing based on chromosomal abnormality type.
• To develop an algorithm for excluding aneuploid embryos using likelihood of euploidy.
• To correlate embryo morphokinetics with the complexity of chromosomal disorders.

Main Methods:

• Retrospective cohort study of 485 embryos from 112 PGS patients.
• Embryo culture using time-lapse technology to record cleavage timing (Day 3).
• Logistic regression analysis to identify morphokinetic parameters associated with aneuploidy.

Main Results:

• Specific morphokinetic parameters, t3 and t5-t2, showed strong associations with complex aneuploid embryos.
• Cleavage timing differences were more pronounced with increased complexity of chromosomal disorders.
• Time-lapse monitoring identified embryos at high risk for complex chromosomal abnormalities.

Conclusions:

• Embryo morphokinetics are significantly influenced by chromosomal aneuploidy.
• Time-lapse monitoring, while not diagnostic, can aid in discarding embryos with a high risk of complex chromosomal abnormalities.
• This approach may improve the selection of euploid embryos for transfer in IVF cycles.