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Updated: Oct 18, 2026
Morphometric Protocol for the Objective Assessment of Blastocyst Behavior During Vitrification and Warming Steps
Published on: February 28, 2019
Universal single-step warming of vitrified blastocysts: feasibility across two commercial kits and comparison with
Yingzhuo Gao1, Lodovico Parmegiani2, Gabor Vajta3
1Center of Reproductive Medicine, National Health Commission Key Laboratory of Advanced Reproductive Medicine and Fertility, Shengjing Hospital of China Medical University, Shenyang, 110004, China.
Abstract:
Conventional vitrification systems for human gametes and embryos typically necessitate brand-specific warming solutions. This retrospective longitudinal cohort study on 2,563 vitrified/warmed blastocysts investigates the efficacy of a universal single-step warming (USSW) protocol for human blastocysts vitrified using distinct commercial systems, combining vitrification and warming kits from two manufacturers: Kitazato (Japan) and VitaVitro Biotech (China) according two different warming protocols: the conventional protocol (UW) or with the single-step warming (USSW). Cryo-survival was 100% across all groups. Clinical and ongoing pregnancy, miscarriage, and live birth rates were comparable among groups. Implantation rate differed overall (p = 0.03), but no pairwise differences remained significant after Bonferroni correction. This study provides preliminary evidence suggesting that the universal single-step warming (USSW) protocol may simplify kit interchangeability and shorten the warming procedure.
