Embryo Selection Based on Morphological Parameters in a Single Vitrified-Warmed Blastocyst Transfer Cycle

Area of Science:

• Reproductive Medicine
• Embryology
• In Vitro Fertilization

Background:

• Embryo selection is critical for improving pregnancy outcomes in assisted reproductive technologies.
• Vitrified-warmed blastocyst transfer (VBT) cycles require robust methods for identifying viable embryos.
• Morphological assessment of blastocysts before and after warming is essential for predicting success.

Purpose of the Study:

• To analyze pre-vitrified and post-warmed blastocyst morphological factors in single VBT cycles.
• To identify key indicators for selecting high-quality embryos to enhance ongoing pregnancy rates.
• To optimize the embryo selection process in VBT procedures.

Main Methods:

• Retrospective cohort study of 329 single VBT cycles.
• Analysis of pre-vitrified and post-warmed blastocyst morphological characteristics.
• Logistic regression analysis to determine factors predicting ongoing pregnancy.

Main Results:

• Pre-vitrified blastocoel expansion (mid and expanded grades) significantly predicted ongoing pregnancy.
• Post-warmed inner cell mass (ICM) grade B and C were associated with lower odds of ongoing pregnancy.
• Day 5 blastocysts showed significantly higher ongoing pregnancy rates compared to Day 6 blastocysts.

Conclusions:

• Selecting Day 5 blastocysts with higher pre-vitrified expansion grades is recommended for VBT.
• Post-warmed ICM grade is a crucial indicator for selecting the optimal blastocyst for single embryo transfer.
• These findings can improve blastocyst selection strategies and enhance pregnancy success in VBT cycles.