Comparison Between Three Freezing Protocols to Preserve Human Embryos
Condition: Human Embryo Cryopreservation
Study type: Interventional

Summary: 
      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.
    

Detailed 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.
    

Intervention name(s): Slow freezing; VIT-Irvine; Vit-Vitrolife
Intervention type(s): Other; Other; Other
Intervention description(s): Embryos at different developmental stages will be frozen using a solution that contains propanediol and sucrose, individually placed in high security straws, cooled with a programmator and stored in liquid nitrogen.; Embryos at different developmental stages will be frozen using the vitrification solution according to the manufacturer's instructions, individually placed in high security vitrification devices and plunged directly in liquid nitrogen for storing.; Embryos at different developmental stages will be frozen using the vitrification solution according to the manufacturer's instructions, individually placed in high security vitrification devices and plunged directly in liquid nitrogen for storing.
Other intervention name(s): Home-made solutions; propanediol; IRVINE, California; ethylene glycol; DMSO; VITROLIFE, Sweden; ethylene glycol; propanediol
Intervention MeSH terms: Ethylene
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: IVF; embryo cryopreservation; vitrification; Human Embryo; Embryonic development; Pregnancy rate