NCT00886431

Vitrification Versus Slow Cooling of Human Cleavage Stage Embryos

A Double Blinded, Randomised Controlled Trial Comparing the Effectiveness of Vitrification to Slow Cooling in Cryopreserving Human Preimplantation Embryos

• Status: Terminated
• Phase: N/A
• Study type: Interventional
• Enrollment: 146 (actual)
• Sponsor: UMC Utrecht · Academic / Other
• Sex: All
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

Summary

Human embryos can be preserved for later transfers by freezing. Traditionally the slow cooling method has been used. About 70% of the embryos remain fully intact after thawing. However, the remaining 30% of the embryos become (partially) damaged, and this freezing damage reduces their chance to implant. Recently an ultra rapid freezing method, called vitrification has been developed. During vitrification no damaging ice crystals are formed and the embryo freezes in a glass like state. It appears that the freezing damage is reduced when embryos are vitrified. Observational studies in humans indicate that embryos are successfully preserved by vitrification, as indicated by promising pregnancy rates following thawing. However, the effectiveness of vitrification in relation to slow cooling with respect to pregnancy rates has so far not been evaluated by a randomised, controlled trial. The aim of this study is to investigate whether vitrification significantly improves embryo survival and ongoing pregnancy rates when compared to embryos frozen by slow cooling.

Detailed description

time of allocation: following embryo selection type of embryos: cleavage stage -, morula stage or early blastocyst stage embryo (day3 - day4 after oocyte collection) cryoprotectants: sucrose, dimethylsulfoxide, ethyleneglycol vitrification storage device: high security vitrification straws

Conditions

• Infertility

Interventions

Type	Name	Description
OTHER	embryo vitrification	Ultra rapid cooling of embryos by immersion in liquid nitrogen. The formation of potentially damaging ice crystals is prevented by briefly incubating the embryos in high concentrations of a mix of cryoprotectants.

Timeline

• Start date: 2009-05-01
• Primary completion: 2012-05-01
• First posted: 2009-04-23
• Last updated: 2014-12-02

Locations

2 sites across 2 countries: Belgium, Netherlands