Vitrification Versus Slow Cooling of Human Cleavage Stage Embryos

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00886431
Recruitment Status : Terminated
First Posted : April 23, 2009
Last Update Posted : December 2, 2014
Vrije Universiteit Brussel
Information provided by (Responsible Party):
Bart CJM Fauser, UMC Utrecht

Brief 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.

Condition or disease Intervention/treatment Phase
Infertility Other: embryo vitrification Not Applicable

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

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 146 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary Purpose: Treatment
Official Title: A Double Blinded, Randomised Controlled Trial Comparing the Effectiveness of Vitrification to Slow Cooling in Cryopreserving Human Preimplantation Embryos
Study Start Date : May 2009
Actual Primary Completion Date : May 2012

Arm Intervention/treatment
Experimental: Vitrification
The embryos of patients allocated to this arm will be cryopreserved by vitrification.
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.
Other Names:
  • vitrification
  • high security vitrification straws

No Intervention: Slow cooling
The embryos of patients allocated to this arm will be cryopreserved by the slow cooling method, which is the standard method (=no intervention)

Primary Outcome Measures :
  1. The percent change of the ongoing pregnancy rate per patient/couple who use their thawed embryos (following a fesh embryo transfer which did not result in an ongoing pregnancy) from baseline (slow cooling) to end point (vitrification). [ Time Frame: ongoing pregnancy is established 10 weeks following the transfer of a frozen embryo ]

Secondary Outcome Measures :
  1. post-thaw embryo survival rate [ Time Frame: 1 hour after thawing ]
  2. ongoing pregnancy rate per patient using their thawed embryos (independent of whether they became pregnant following a fresh embryo transfer or not [ Time Frame: 10 weeks following transfer of frozen thawed embryo ]
  3. implantation rate per thawed embryo [ Time Frame: 10 weeks after transfer of thawed embryo ]
  4. implantation rate per transferred thawed embryo [ Time Frame: 10 weeks after transfer of thawed embryo ]
  5. cumulative implantation rate per cryopreservation [ Time Frame: 10 weeks after thawed embryo transfer ]
  6. ongoing pregnancy rate per frozen-thaw cycle [ Time Frame: 10 weeks following thawed embryo transfer ]
  7. average number of frozen-thawed cycles per patient [ Time Frame: is variable ]
  8. post thaw development (categorial) per thawed embryo [ Time Frame: 24 hours following thawing ]
  9. average number of cryo-thaw cycles to ongoing pregnancy [ Time Frame: variable, up to 3 years ]
  10. average number of thawed embryos to ongoing implantation [ Time Frame: variable, up to 3 years ]
  11. Life birth rate [ Time Frame: 9 month after pregnancy test ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • female patient age 35 years or less
  • embryos are obtained by in vitro fertilization (IVF) or intra cytoplasmatic spermatozoon injection (ICSI)
  • single embryo transfer
  • 1rst IVF/ICSI treatment with an embryo transfer
  • availability of cryopreservable embryos

Exclusion Criteria:

  • female patient age is 36 years or older
  • participants of oocyte donation program
  • participants of percutaneous spermatozoon aspiration (PESA) program
  • couples with a finite source of spermatozoa
  • absence of cryopreservable embryos

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00886431

Academic Hospital of Brussels
Brussels, Belgium, 1090
University Medical Center of Utrecht
Utrecht, Netherlands, 3584 CX
Sponsors and Collaborators
UMC Utrecht
Vrije Universiteit Brussel
Principal Investigator: Bart C Fauser, Prof.,MD,PhD UMC Utrecht


Responsible Party: Bart CJM Fauser, Prof. dr. B Fauser, UMC Utrecht Identifier: NCT00886431     History of Changes
Other Study ID Numbers: Vitrification study
CCMO NL23499.000.08
METC 08/183
First Posted: April 23, 2009    Key Record Dates
Last Update Posted: December 2, 2014
Last Verified: November 2014

Keywords provided by Bart CJM Fauser, UMC Utrecht:
embryo cryopreservation
slow cooling
slow freezing
surplus embryos
Human Reproduction

Additional relevant MeSH terms:
Genital Diseases, Male
Genital Diseases, Female