Oocyte Cryopreservation: Slow Cooling Versus Vitrification Techniques on Oocyte Survival

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: NCT00602966
Recruitment Status : Completed
First Posted : January 28, 2008
Last Update Posted : October 28, 2011
EMD Serono
Information provided by (Responsible Party):
Claudio Benadiva, University of Connecticut Health Center

Brief Summary:

Oocyte cryopreservation has been studied for many years without much success in refining a method that has consistent, reliable results in producing viable embryos and clinical pregnancies. In 1986 the first baby was born from an embryo created from a frozen oocyte; however, since then there have been less than 150 births from frozen eggs. To date, there are no reportable adverse outcomes in the children born from frozen oocytes. The research continues to look at different methods of oocyte cryopreservation. Many smaller studies have been conducted with some success but larger clinical trials are needed to replicate these findings. The conventional cryopreservation technique has been slow cooling with differing methods of freezing; however, vitrification is now being researched as the potential cryopreserving method that holds some promise for the future.

Our hypothesis is the use of vitrification (quick freezing) to cryopreserve oocytes in patients undergoing in-vitro fertilization will be more successful than slow freezing in oocyte survival, fertilization rate with ICSI and subsequent embryo development, implantation rate and pregnancy rate.

Condition or disease

Detailed Description:

Cryopreservation of oocytes is desirable because it: 1) would allow infertility patients to store excess oocytes instead of embryos, eliminating some of the ethical and religious concerns that accompany embryo storage; 2) permit storage of donor oocytes to avoid donor-recipient synchronization difficulties; and 3) can help women who may face sterilization due to chemotherapy or radiation. Oocyte cryopreservation is therefore gaining in popularity as an option for infertility treatment as well as fertility preservation.

Oocyte cryopreservation using conventional slow-cooling methods has not had much success; however more recent results have provided more optimism (Boldt et al., 2003; Porcu et al., 1997; 2000; 2002; Yang et al., 1998; 1999; 2002; Winslow et al., 2001). Vitrification has also been employed (Hong et al., 1999; Kuleshova et al., 1999; Yoon et al., 2000, 2003; Chung et al 2000; Wu et al., 2001: Kuwayama et al., 2005) with increased oocyte survival rate and live births. Vitrification is performed by suspending the oocytes in a solution containing a high concentration of cryoprotectants and then plunging them directly into liquid nitrogen (Rall and Fahy, 1985). The advantage of this technique is to prevent the formation of ice crystals within the oocyte. However the toxic effect of the high concentration of the cryoprotectant media has been a concern. New vitrification techniques which attempt to accelerate the cooling rate by decreasing the cryosolution volume and concentration, may reduce the potential toxicity. In addition, a more rapid cooling rate results in reduced chilling injury (Vajta et al., 1998).

Study Type : Observational
Actual Enrollment : 14 participants
Observational Model: Case Control
Time Perspective: Prospective
Official Title: Oocyte Cryopreservation: Comparison of Slow Cooling Versus Vitrification Techniques on Oocyte Survival, Fertilization, and Embryo Development
Study Start Date : July 2006
Actual Primary Completion Date : October 2009
Actual Study Completion Date : May 2010

Slow Freeze

Primary Outcome Measures :
  1. Oocyte survival [ Time Frame: When patient returns for thaw cycle ]

Secondary Outcome Measures :
  1. Implantation rate [ Time Frame: 2 weeks after transfer of thawed oocyte ]

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Ages Eligible for Study:   21 Years to 36 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Probability Sample
Study Population
The Center for Advanced Reproductive Services patient population

Inclusion Criteria:

  • Patients ≤ 36 years old
  • Day #3 follicle stimulation hormone (FSH) < 10mIU/ml, and Estradiol < 70 pg/ml.
  • The study will be limited to couples who do not wish to cryopreserve excess embryos, who would otherwise have their excess oocytes discarded.
  • Body Mass Index (BMI) ≤ 35
  • Patients currently being seen in our offices

Exclusion Criteria:

  • Male partner requiring microsurgical epididymal sperm aspiration or testicular sperm extraction (MESA/TESE) for sperm retrieval
  • Day #3 follicle stimulation hormone (FSH) > 10mIU/ml, or estradiol > 70 pg/ml
  • Diagnosis of Polycystic Ovary Syndrome (PCOS)
  • Body Mass Index (BMI) >35

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): NCT00602966

United States, Connecticut
The Center for Advanced Reproductive Services
Farmington, Connecticut, United States, 06030-6224
Sponsors and Collaborators
UConn Health
EMD Serono
Principal Investigator: Claudio Benadiva, MD, HCLD The Center for Advanced Reproductive Services, P.C.


Responsible Party: Claudio Benadiva, Laboratory Director and Director of the Preimplantation Genetics Diagnosis Program,, University of Connecticut Health Center Identifier: NCT00602966     History of Changes
Other Study ID Numbers: 06-336-2
First Posted: January 28, 2008    Key Record Dates
Last Update Posted: October 28, 2011
Last Verified: October 2011

Keywords provided by Claudio Benadiva, University of Connecticut Health Center:
Oocyte cryopreservation
slow freeze

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