A review of best practices of rapid-cooling vitrification for oocytes and embryos: a committee opinion

This committee opinion reviews background of vitrification, defines terminology, and determines best practices for rapid-cooling vitrification of oocytes and embryos.

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VOLUME 115, ISSUE 2, P305-310


Practice Committees of the American Society for Reproductive Medicine and Society of Reproductive Biologists and Technologists 


The focus of this paper is to review best practices for rapid-cooling cryopreservation of oocytes and embryos. The discussion of best practices includes the types of cryoprotectants and cryo devices typically used. Key performance indicators of rapid-cooling vitrification success are defined.

Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. 


Go to the profile of Yoshimasa Yokota
7 months ago

Dear Editor,

I am very interested in your article “a review of best practices of rapid-cooling vitrification for oocytes and embryos: a committee opinion” on Fertil Steril 2021,115:305-309.


I hope it will be added one point my opinion.

You showed a first delivery after human blastocyst rapid cooling by Mukaida et al. 2001 on supplement table 1.  However, we already published the Hum Reprod 15:1802-3, 2000 (1) and Fertil Steril 75: 1027-29, 2001 (2). So, our publication was earlier than them.  Also, Stachecki JJ referred our paper in his publication (3) and another, Lucinda L, Veek referred our paper in her Atlas of Human Blastocysts book.


Today we widely used for general vitrification reagent which contained ethylene glycol/DMSO for human embryos cryopreservation. The application of this freezing agents to human embryo was epoch-making. Therefore, best of our knowledge, we believe that we used the first successful delivery baby from human blastocysts using ethylene glycol/DMSO on June 23, 2000 in the world.

We look forward to quoting our achievements at the next opportunity.



  • Yokota Y, Sato S, Yokota M, Ishikawa Y, Makita M, Asada T, Araki Y: Successful pregnancy following blastocyst vitrification: case report. Hum Reprod 2000; 15:1802-3

  • Yokota Y, Sato S, Yokota M, Yokota H, Araki Y: Birth of a healthy baby following vitrification of human blastocysts. Fertil Steril 2001; 75:1027-9.

  • Stachecki JJ, Garrisi J, Sabino S, Caetano JP, Wiemer KE, Cohen J. A new safe, simple and successful vitrification method for bovine and human blastocysts. Reprod Biomed Online 2008; 17:360-7.


Best regards.


Yoshimasa Yokota, M.D.

Yokota Maternity Hospital, 1-16-5, Shimokoide, Gunma 371-0031, Japan.

E-mail: aikoukai@olive.ocn.ne.jp