Comparison Between Three Freezing Protocols to Preserve Human Embryos

Free University of Brussels (ULB)

Status: Completed

Conditions: Human Embryo Cryopreservation

Treatments: Other: VIT-Irvine; Other: Slow freezing; Other: Vit-Vitrolife

Study type: Interventional

Funder types: Other

Identifiers

NCT00910390

VITR-1-EMBRYOS

Details and patient eligibility

About

This randomized study compares three different freezing methods to store human in vitro fertilization (IVF) embryos: vitrification with two commercial kits or slow freezing. After information, all patients undergoing IVF treatment can be included in the study. If qualified, embryos at different developmental stages will be allocated between the three methods. At the end of the first year survival and developmental rates, and implantation and pregnancy rates will be analyzed in order to determine the best method.

Full description

Despite all the advances achieved in vitro fertilized treatments, it is known that the chances of implantation for fertilised in vitro embryo remain limited, at around 20%. Cryopreservation of supernumerary embryos produced during IVF cycles provides an opportunity for patients to increase the number of transfers per oocyte harvest cycle, increasing then their chances of conception.

The freezing technique may involve different media and methods, which lead to different survival and developmental rates after thawing.

Vitrification is a new freezing method, which consists in exposing cells to high concentrations of cryoprotectants and then cooling them ultra-rapidly; this induces an increase in viscosity which favours the formation of a vitreous state without any ice crystals formation. This method contrasts with the slow freezing method (currently employed), which is based on exposure to very low concentrations of cryoprotectants combined with long cooling times and associated with a higher risk of ice crystal formation.

Both methods can reduce cell survival and embryo ability to develop, either by the high concentrations of cryoprotectants in case of vitrification, or by ice crystals formation in case of slow freezing. The advantages of vitrification in embryology may be considerable because embryos seem more sensitive to ice crystal formation than to cyroportectant concentration; consequently, the elimination of office crystal injury may increase their survival chances. Additionally in the case of vitrification, the time required for equilibration and cooling is considerably reduced as well as the need for expensive equipment such as programmable machine is eliminated.

At present, vitrification and slow freezing are used for the cryopreservation of oocytes and embryos at all stages of development. Encouraging results have been obtained with vitrification, but no study has randomly compared in one study, the two protocols and cryoprotectors. The purpose of this clinic randomised study is to compare three treatments: traditional slow freezing method currently employed (control group) and two different commercial vitrification methods (experimental groups) to assess the efficacy that this technique may involve.

Enrollment: 584 patients

Sex: Female

Ages: 18 to 43 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Infertility requiring IVF

Exclusion criteria

• Women's age > 43 years
• Patients positive for hepatitis B or C
• Patients positive for HIV

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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584 participants in 3 patient groups, including a placebo group

Slow Freezing

Placebo Comparator group

Description:

Standard freezing protocol (slow freezing) of preimplantation embryos

Treatment:

Other: Slow freezing

VIT-Irvine

Experimental group

Description:

Vitrification with Irvine solution (rapid freezing) of preimplantation embryos

Treatment:

Other: VIT-Irvine

VIT-Vitrolife

Experimental group

Description:

Vitrification (rapid freezing) with Vitrolife solution

Treatment:

Other: Vit-Vitrolife