Clinical trial NCT00602966: Oocyte Cryopreservation: Slow Cooling Versus Vitrification Techniques on Oocyte Survival
Official title: Oocyte Cryopreservation: Comparison of Slow Cooling Versus Vitrification Techniques on Oocyte Survival, Fertilization, and Embryo Development
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Infertility
Keywords: Oocyte cryopreservation
slow freeze
vitrification
Lead sponsor: UConn Health
Sponsor class: OTHER
Collaborators: name: EMD Serono
First posted: 2008-01-28
Enrollment: 14
Sex: FEMALE
Minimum age (years): 21
Maximum age (years): 36
Standard ages: ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CONTROL
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: The Center for Advanced Reproductive Services patient population

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.

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).

Eligibility criteria: 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

Primary outcomes:
measure: Oocyte survival
timeFrame: When patient returns for thaw cycle
Secondary outcomes:
measure: Implantation rate
timeFrame: 2 weeks after transfer of thawed oocyte
Other outcomes:
Locations:
city: Farmington
country: United States
facility: The Center for Advanced Reproductive Services
state: Connecticut
Study officials:
affiliation: The Center for Advanced Reproductive Services, P.C.
name: Claudio Benadiva, MD, HCLD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Boldt J, Cline D, McLaughlin D. Human oocyte cryopreservation as an adjunct to IVF-embryo transfer cycles. Hum Reprod. 2003 Jun;18(6):1250-5. doi: 10.1093/humrep/deg242.
citation: Carroll J, Depypere H, Matthews CD. Freeze-thaw-induced changes of the zona pellucida explains decreased rates of fertilization in frozen-thawed mouse oocytes. J Reprod Fertil. 1990 Nov;90(2):547-53. doi: 10.1530/jrf.0.0900547.
citation: Fuku E, Xia L, Downey BR. Ultrastructural changes in bovine oocytes cryopreserved by vitrification. Cryobiology. 1995 Apr;32(2):139-56. doi: 10.1006/cryo.1995.1013.
citation: Hong SW, Chung HM, Lim JM, Ko JJ, Yoon TK, Yee B, Cha KY. Improved human oocyte development after vitrification: a comparison of thawing methods. Fertil Steril. 1999 Jul;72(1):142-6. doi: 10.1016/s0015-0282(99)00199-5.
citation: Kuleshova L, Gianaroli L, Magli C, Ferraretti A, Trounson A. Birth following vitrification of a small number of human oocytes: case report. Hum Reprod. 1999 Dec;14(12):3077-9. doi: 10.1093/humrep/14.12.3077.
citation: Porcu E, Fabbri R, Seracchioli R, Ciotti PM, Magrini O, Flamigni C. Birth of a healthy female after intracytoplasmic sperm injection of cryopreserved human oocytes. Fertil Steril. 1997 Oct;68(4):724-6. doi: 10.1016/s0015-0282(97)00268-9.
citation: Porcu E, Fabbri R, Damiano G, Giunchi S, Fratto R, Ciotti PM, Venturoli S, Flamigni C. Clinical experience and applications of oocyte cryopreservation. Mol Cell Endocrinol. 2000 Nov 27;169(1-2):33-7. doi: 10.1016/s0303-7207(00)00348-8.
citation: Rall WF, Fahy GM. Ice-free cryopreservation of mouse embryos at -196 degrees C by vitrification. Nature. 1985 Feb 14-20;313(6003):573-5. doi: 10.1038/313573a0.
citation: Stachecki JJ, Cohen J, Willadsen S. Detrimental effects of sodium during mouse oocyte cryopreservation. Biol Reprod. 1998 Aug;59(2):395-400. doi: 10.1095/biolreprod59.2.395.
citation: Stachecki JJ, Cohen J, Willadsen SM. Cryopreservation of unfertilized mouse oocytes: the effect of replacing sodium with choline in the freezing medium. Cryobiology. 1998 Dec;37(4):346-54. doi: 10.1006/cryo.1998.2130.
citation: Stachecki JJ, Cohen J, Schimmel T, Willadsen SM. Fetal development of mouse oocytes and zygotes cryopreserved in a nonconventional freezing medium. Cryobiology. 2002 Feb;44(1):5-13. doi: 10.1016/S0011-2240(02)00007-X.