Shortened warming preserves cellular resilience and accelerates post-warming development in human blastocysts: A...

Area of Science:

• Embryology and Reproductive Medicine
• Cryobiology
• Assisted Reproductive Technologies

Background:

• Conventional multi-step warming protocols (MWP) for vitrified blastocysts are time-consuming and prone to variability.
• Optimizing warming protocols is crucial for improving the efficiency and success rates of assisted reproductive technologies.

Purpose of the Study:

• To evaluate the efficacy of a shortened warming protocol (SWP) for vitrified blastocysts.
• To compare post-warming recovery and developmental competence between SWP and MWP.

Main Methods:

• Retrospective propensity score-matched cohort study of 546 vitrified-warmed blastocyst transfer cycles.
• Time-lapse imaging to assess re-expansion and hatching times (tSRE, tCRE, tHSP).
• Evaluation of morphological recovery, blastocyst quality score (BQS), and inner cell mass (ICM) and trophectoderm (TE) grades.

Main Results:

• SWP demonstrated significantly faster post-warming recovery (shorter tSRE, tCRE, tHSP) compared to MWP (P < 0.01).
• Higher proportion of blastocysts with improved morphology and Grade A ICM/TE in the SWP group (P < 0.05).
• No significant difference in hatching stages or clinical pregnancy outcomes between SWP and MWP groups.

Conclusions:

• SWP provides efficient and biologically stable post-warming recovery for vitrified blastocysts.
• SWP does not compromise embryonic quality or clinical outcomes compared to MWP.
• SWP represents a promising alternative to conventional warming protocols in assisted reproduction.