Ultra-rapid Blastocyst Vitrification: Pilot Randomized Study

NCT07556601 | Not Yet Recruiting

• 1 other identifier: FSD-UFV-2026-04
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 2

Brief Summary

Blastocyst vitrification is standard in assisted reproduction, but clinical data on ultra-rapid vitrification are limited. This pilot study evaluates the safety, feasibility, and preliminary clinical performance of an ultra-rapid blastocyst vitrification protocol compared with the standard approach.

Conditions

Infertility

Outcome Measures

Primary Outcomes (2)

• Post-warming survival rate

  the proportion of vitrified blastocysts that remain morphologically viable after warming, expressed as a percentage of all warmed blastocysts.

  Immediately after warming (within the same laboratory session)

• Clinical pregnancy rate per transfer (only first transfer will be considered).

  defined as the proportion of embryo transfers resulting in a clinical pregnancy, confirmed by the presence of an intrauterine gestational sac on ultrasound. Only the first embryo transfer per patient is included in the analysis.

  6-8 weeks after embryo transfer

Secondary Outcomes (4)

• Blastocyst re-expansion

  Within 2 hours after warming

• Post-warming blastocyst morphokinetic parameters

  From embryo warming until embryo transfer (within 2-6 hours post-warming)

• Post-warming blastocyst morphological quality

  From embryo warming until embryo transfer (within 2-6 hours post-warming)

• Technical or embryological adverse events.

  From blastocyst warming until embryo transfer, within the same clinical procedure (up to 6 hours post-warming)

Study Arms (2)

Standard Vitrification Protocol

ACTIVE COMPARATOR

The standard vitrification protocol corresponds to the routine clinical practice of the laboratory and consists of the following steps: 1. Equilibration step: Blastocysts are equilibrated in Equilibration Solution (ES) for 10-12 minutes at room temperature. 2. Vitrification solution exposure: Blastocysts are then transferred to Vitrification Solution (VS) for a maximum exposure time of 90 seconds. 3. Loading: The blastocyst is loaded onto a Cryotop device (Kitazato). 4. Vitrification: The Cryotop is plunged directly into liquid nitrogen within 1 second of loading to ensure ultra-rapid cooling. 5. Capping: The Cryotop is immediately capped under liquid nitrogen conditions.

Other: Standard Vitrification

Ultra-Rapid Vitrification Protocol

EXPERIMENTAL

The ultra-rapid vitrification protocol is identical to the standard protocol in terms of media, devices, and laboratory conditions, with the following modifications: Preparation step - Blastocyst shrinkage: Prior to equilibration, artificial collapse of the blastocyst is performed using a single laser pulse to induce blastocoel shrinkage. The subsequent steps are: 1\. Equilibration step: Blastocysts are equilibrated in Equilibration Solution (ES) for 2-4 minutes. Vitrification solution exposure: Transfer to Vitrification Solution (VS) for a maximum of 90 seconds. 3\. Loading: Loading of the blastocyst onto a Cryotop device. 4. Vitrification: Immediate plunging of the Cryotop into liquid nitrogen within 1 second. 5\. Capping: Immediate capping under liquid nitrogen.

Other: Ultra-Rapid Vitrification

Interventions

Standard Vitrification OTHER

1. Equilibration step: Blastocysts are equilibrated in Equilibration Solution (ES) for 10-12 minutes at room temperature. 2. Vitrification solution exposure: Blastocysts are then transferred to Vitrification Solution (VS) for a maximum exposure time of 90 seconds. 3. Loading: The blastocyst is loaded onto a Cryotop device (Kitazato). 4. Vitrification: The Cryotop is plunged directly into liquid nitrogen within 1 second of loading to ensure ultra-rapid cooling. 5. Capping: The Cryotop is immediately capped under liquid nitrogen conditions.

Standard Vitrification Protocol

Ultra-Rapid Vitrification OTHER

The ultra-rapid vitrification protocol is identical to the standard protocol in terms of media, devices, and laboratory conditions, with the following modifications: Preparation step - Blastocyst shrinkage: Prior to equilibration, artificial collapse of the blastocyst is performed using a single laser pulse to induce blastocoel shrinkage. The subsequent steps are: 1. Equilibration step: Blastocysts are equilibrated in Equilibration Solution (ES) for 2-4 minutes. 2. Vitrification solution exposure: Transfer to Vitrification Solution (VS) for a maximum of 90 seconds. 3. Loading: Loading of the blastocyst onto a Cryotop device. 4. Vitrification: Immediate plunging of the Cryotop into liquid nitrogen within 1 second. 5. Capping: Immediate capping under liquid nitrogen.

Ultra-Rapid Vitrification Protocol

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Recipients of donor oocytes
• Blastocysts suitable for cryopreservation

You may not qualify if:

• Cycles involving PGT
• Cycles not reaching blastocyst stage.

Sponsors & Collaborators

• Fundacion Dexeus: lead

Study Sites (2)

Hospital Universitario Quiron Dexeus

Barcelona, 08028, Spain

Location

Hospital Universitario Quiron Dexeus

Barcelona, 08028, Spain

Location

Related Publications (11)

• Boyard J, Reignier A, Chtourou S, Lefebvre T, Barriere P, Freour T. Should artificial shrinkage be performed prior to blastocyst vitrification? A systematic review of the literature and meta-analysis. Hum Fertil (Camb). 2022 Feb;25(1):24-32. doi: 10.1080/14647273.2019.1701205. Epub 2020 Jan 24.

  PMID: 31973647 BACKGROUND

• George JS, Keefe KW. Freezer burn or learning curve? Prolonged time since blastocyst vitrification and impact on pregnancy outcomes. Fertil Steril. 2023 Jan;119(1):45-46. doi: 10.1016/j.fertnstert.2022.11.017. Epub 2022 Nov 19. No abstract available.

  PMID: 36410446 BACKGROUND

• Gunst J, Joris H, Vynck M, Godderis K, Vercammen M, Roggeman S, van de Vijver A. Validation and clinical study of single-step vitrification combined with single-step warming of human blastocysts. J Assist Reprod Genet. 2026 Mar;43(3):837-850. doi: 10.1007/s10815-025-03790-1. Epub 2026 Feb 13.

  PMID: 41686351 BACKGROUND

• Kovacic B, Taborin M, Vlaisavljevic V, Reljic M, Knez J. To collapse or not to collapse blastocysts before vitrification? A matched case-control study on single vitrified-warmed blastocyst transfers. Reprod Biomed Online. 2022 Oct;45(4):669-678. doi: 10.1016/j.rbmo.2022.03.030. Epub 2022 Apr 10.

  PMID: 35963753 BACKGROUND

• Li Z, Wang YA, Ledger W, Edgar DH, Sullivan EA. Clinical outcomes following cryopreservation of blastocysts by vitrification or slow freezing: a population-based cohort study. Hum Reprod. 2014 Dec;29(12):2794-801. doi: 10.1093/humrep/deu246. Epub 2014 Oct 14.

  PMID: 25316444 BACKGROUND

• Martinez-Rodero I, Gallardo M, Pisaturo V, Scarica C, Conaghan J, Liebermann J, Cuevas-Saiz I. Shorter protocols for vitrification and post-warming dilution of human oocytes and embryos: a narrative review. Reprod Biomed Online. 2025 Aug;51(2):104857. doi: 10.1016/j.rbmo.2025.104857. Epub 2025 Feb 7.

  PMID: 40479947 BACKGROUND

• Perez-Sanchez M, Pardinas ML, Diez-Juan A, Quinonero A, Dominguez F, Martin A, Vidal C, Beltran D, Mifsud A, Mercader A, Pellicer A, Cobo A, de Los Santos MJ. The effect of vitrification on blastocyst mitochondrial DNA dynamics and gene expression profiles. J Assist Reprod Genet. 2023 Nov;40(11):2577-2589. doi: 10.1007/s10815-023-02952-3. Epub 2023 Oct 6.

  PMID: 37801195 BACKGROUND

• Rienzi L, Gracia C, Maggiulli R, LaBarbera AR, Kaser DJ, Ubaldi FM, Vanderpoel S, Racowsky C. Oocyte, embryo and blastocyst cryopreservation in ART: systematic review and meta-analysis comparing slow-freezing versus vitrification to produce evidence for the development of global guidance. Hum Reprod Update. 2017 Mar 1;23(2):139-155. doi: 10.1093/humupd/dmw038.

  PMID: 27827818 BACKGROUND

• Sciorio R, Tramontano L, Campos G, Greco PF, Mondrone G, Surbone A, Greco E, Talevi R, Pluchino N, Fleming S. Vitrification of human blastocysts for couples undergoing assisted reproduction: an updated review. Front Cell Dev Biol. 2024 May 17;12:1398049. doi: 10.3389/fcell.2024.1398049. eCollection 2024.

  PMID: 38827525 BACKGROUND

• Sekhon L, Lee JA, Flisser E, Copperman AB, Stein D. Blastocyst vitrification, cryostorage and warming does not affect live birth rate, infant birth weight or timing of delivery. Reprod Biomed Online. 2018 Jul;37(1):33-42. doi: 10.1016/j.rbmo.2018.03.023. Epub 2018 Apr 21.

  PMID: 29706285 BACKGROUND

• Van Landuyt L, Polyzos NP, De Munck N, Blockeel C, Van de Velde H, Verheyen G. A prospective randomized controlled trial investigating the effect of artificial shrinkage (collapse) on the implantation potential of vitrified blastocysts. Hum Reprod. 2015 Nov;30(11):2509-18. doi: 10.1093/humrep/dev218. Epub 2015 Sep 12.

  PMID: 26364080 BACKGROUND

Related Links

• Related Info

MeSH Terms

Conditions

Infertility

Condition Hierarchy (Ancestors)

Genital Diseases; Urogenital Diseases

Central Study Contacts

Monica Parriego, PhD

CONTACT

0034932274700; monpar@dexeus.com

Ignacio Rodríguez, MSc

CONTACT

0034932274700; nacrod@dexeus.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 13, 2026
• First Posted: April 29, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): March 1, 2028
• Last Updated: April 29, 2026

Record last verified: 2026-04

Locations

ES (2)