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Updated: Aug 11, 2026
Modified MicroSecure Vitrification: A Safe, Simple and Highly Effective Cryopreservation Procedure for Human Blastocysts
Published on: March 2, 2017
Optimization of a dilution method for human expanded blastocysts vitrified using EM grids after artificial shrinkage
So-Young Lee1, Hyung-Jun Kim, Sung-Jin Park
1In Vitro Fertilization Laboratory, Maria Infertility Hospital, Dongdaemun-gu, Seoul, South Korea. snail0@mariababy.com
Purpose:
To verify a more effective dilution method that can be applied to human expanded blastocysts that are vitrified after artificial shrinkage.
Methods:
Surplus expanded blastocysts that remained after embryo transfer (ET) in in vitro fertilization (IVF) cycles, were cryopreserved. The blastocysts were vitrified on EM grids following artificial shrinkage. After thawing the blastocysts, cryoprotectants were diluted using either a 6- or 2-step method. We examined the survival rate and clinical outcome of blastocysts of 151 patients in our ET program after thawing.
Results:
The survival rate of blastocysts that were thawed using a 2-step method (91.6%, 239/261) was comparable with that of the 6-step method (89%, 186/209). The clinical pregnancy rate (45.9%, 39/85) and implantation rate (24.1%, 53/220) were slightly higher in the 2-step method than in the 6-step method (40.9%, 27/66; 19.4%, 33/170).
Conclusions:
Our data indicate that the 2-step dilution method could be a simpler and more effective protocol for human expanded blastocysts that are vitrified using EM-grid following artificial shrinkage.
