Frozen Embryo Transfer (FET)DW-FET-RCTNCT06741748
Direct Warming Frozen Embryo Transfer Outcomes in Assisted Reproductive Technology
A study testing Direct Warming Method and Conventional Multi-step Thawing Method in people with Frozen Embryo Transfer (FET) and Assisted Reproductive Techniques, run by Chinese University of Hong Kong at 3 sites in 2 countries.
Trial summary
The goal of this clinical trial is to evaluate whether the direct warming method for frozen embryo transfers (FET) can improve live birth and pregnancy outcomes in women aged 18-45 undergoing IVF treatments. Read more about this study
- Who is it for?
- Ages 18 to 45 years, women only
- Conditions the study is for
- Frozen Embryo Transfer (FET), Assisted Reproductive Techniques, In Vitro Fertilization (IVF)
- What is being tested?
- Direct Warming Method and Conventional Multi-step Thawing Method
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 578 participants
- Where
- 3 sitesin 2 countries
- Study dates
- 1 Sep 2025to 31 Oct 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Plan to undergo single embryo transfer (SET) during the FET cycle.
- Age between 18 and 45 years.
- Patients with at least one high-quality blastocyst available for transfer.
- Patients who have provided informed consent to participate in the study.
Who cannot join
- Patients with repeated implantation failure (RIF) or recurrent miscarriage (RM).
- Patients with known uterine anomalies or significant uterine pathology (e.g., fibroids, polyps).
- Patients who are unwilling or unable to provide informed consent.
Trial locations and contacts
3 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
3 sites in 2 countries
Hong Kong2 sites
The Chinese University of Hong Kong
Shatin, New Territories, Hong Kong SAR
(852) 3505 1764
The CUHK Medical centre
Shatin,NT, Hong Kong SAR
Yiu Leung, David Chan, +852 3946 6888, drdcyl16@cuhk.edu.hk
United Kingdom1 site
The Homerton Hospital
London, London
Priya Bhide, 020 8510 5555, p.bhide@qmul.ac.uk
About this study
Official title: A Pragmatic, Multi-centre, Double-blinded, Two-arm Randomized Controlled Trial on a Direct Warming Frozen Embryo Transfer in Assisted Reproductive Technologies Treatment Outcome
The goal of this clinical trial is to evaluate whether the direct warming method for frozen embryo transfers (FET) can improve live birth and pregnancy outcomes in women aged 18-45 undergoing IVF treatments. The main questions it aims to answer are:
- Does the direct warming method achieve a similar or higher clinical success rate for FET compared to the conventional multi-step method?
- Is the direct warming method more cost-effective than the conventional method?
Read more
Researchers will compare the direct warming method to the conventional multi-step method to see if the former leads to better pregnancy outcomes and reduced procedural time.
Participants will:
- Undergo either the one-step or conventional embryo thawing procedure.
- Complete standard clinical follow-ups for pregnancy, including ultrasound scans and pregnancy tests.
Read the detailed description
This clinical trial explores a novel direct warming method for frozen embryo transfer (FET), aimed at improving both clinical and operational outcomes in assisted reproductive technologies (ART). The method was designed to simplify and accelerate the embryo thawing process, reducing the time needed for thawing while eliminating the use of cryoprotectants commonly required in conventional thawing methods. This innovation has the potential to offer a more efficient and cost-effective alternative to standard FET procedures.
The primary focus of this trial is to compare the clinical effectiveness of the direct warming method against the conventional multi-step thawing process. In particular, the study seeks to determine whether the new method yields comparable or superior outcomes in terms of clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), and live birth rate (LBR), while also assessing its overall cost-effectiveness.
Study Design and Technical Details
This study employs a randomized controlled design, with participants being allocated into either the intervention group (direct warming method) or the control group (conventional multi-step thawing). The direct warming method streamlines the thawing process to just 3 minutes, in contrast to the conventional method, which requires multiple stages and takes approximately 20 minutes. By using only an embryo culture medium without cryoprotectants, the direct warming method reduces both complexity and potential risks associated with handling and cryoprotectant toxicity.
Key Objectives
- Primary Objective: To evaluate the clinical efficacy of the direct warming method in achieving comparable or higher success rates for FET as compared to conventional multi-step thawing.
- Secondary Objective: To assess the cost-effectiveness of the direct warming method by comparing the consumable and time costs across different centers.
Expected Impact and Innovation
The direct warming method challenges the traditional multi-step thawing approach, offering a faster and simpler alternative without compromising clinical outcomes. By minimizing the need for cryoprotectants and reducing the complexity of the thawing process, the new method is expected to enhance the overall efficiency of FET procedures while maintaining or improving pregnancy success rates. Additionally, the cost and time savings associated with the direct warming method may make it a viable option for IVF clinics worldwide, driving standardization and consistency across clinical settings.
- Conditions
- Frozen Embryo Transfer (FET), Assisted Reproductive Techniques, In Vitro Fertilization (IVF), Cryopreservation of Embryos, Pregnancy Outcome After in Vitro Fertilization (IVF)
- Being tested
- Direct Warming Method, Conventional Multi-step Thawing Method
- Keywords
- Direct Warming Method, Frozen Embryo Transfer, Assisted Reproductive Technologies, Cryopreservation, Cost-effectiveness in ART, Embryo Warming, In Vitro Fertilization
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Direct Warming MethodOther
Also called One-step thawing
This intervention involves thawing vitrified blastocysts using a simplified, one-step direct warming method. The blastocyst is placed in a pre-warmed embryo culture medium for approximately one minute, then transferred directly into the embryo culture medium within a time-lapse system until ready for uterine transfer. The total thawing process takes approximately three minutes, reducing the duration and complexity of the procedure compared to conventional methods.
Conventional Multi-step Thawing MethodOther
This intervention involves thawing vitrified blastocysts using a standard, multi-step process. The procedure includes sequential exposure of the blastocyst to different thawing solutions containing varying concentrations of cryoprotectants, followed by its transfer into an embryo culture medium in a time-lapse system. The overall process takes approximately 10-30 minutes.
| Study group | Role | What they receive |
|---|---|---|
| Direct Warming method | Experimental | The blastocyst designated for thawing will be placed in a pre-warmed, direct warming medium for one minute. Afterward, the embryo is transferred into an embryo culture medium within a time-lapse system, where it remains until the patient is ready for the embryo transfer procedure. This direct warming method significantly reduces the total procedure time to approximately 3 minutes, making it about ten times faster than the conventional multi-step thawing method. Receives: Other: Direct Warming Method |
| Conventional multi-step thawing method | Placebo comparator | In the conventional multi-step thawing method, vitrified blastocysts are sequentially thawed using a series of pre-warmed thawing, dilution, and washing solutions. The blastocyst is first placed in a thawing solution for 1-3 minutes, followed by immersion in a dilution solution for 4-6 minutes to reduce cryoprotectant concentration. Finally, the blastocyst is transferred to a washing solution for 5-10 minutes for rehydration. The entire process takes approximately 30 minutes, after which the embryo is placed into an embryo culture medium in a time-lapse system until it is ready for embryo transfer. Receives: Other: Conventional Multi-step Thawing Method |
What is being measured
The primary outcome is the main question the study is designed to answer.
Clinical Pregnancy Rate
Number of participants with at least one intrauterine gestational sac observed on ultrasound at 6-8 weeks of gestation following embryo transfer.
Measured: 6-8 weeks post embryo transfer
Ongoing Pregnancy Rate (OPR)
Number of participants with a viable intrauterine pregnancy observed on ultrasound at 12 weeks of gestation.
Measured: 12 weeks post embryo transfer
Live Birth Rate (LBR)
Number of participants who deliver a live infant after 24 weeks of gestation.
Measured: At delivery, approximately 9 months post embryo transfer
Cost-Effectiveness
A comparative analysis of the total costs, including costs of consumables (e.g., warming mediums, storage devices) and staff labor hours, associated with the direct warming method compared to the conventional multi-step thawing method. Costs will be measured in USD and analyzed at the end of the study period.
Measured: At the end of the study, approximately 4 years.
Secondary outcomes (2)
Subgroup Analysis of Warming Medium
Analysis of the clinical differences between brands of warming mediums assessing their impact on embryo survival rate.
Measured: Throughout the study period, approximately 4 years.
Subgroup Analysis of Storage Devices
Analysis of the clinical differences between brands of Storage Devices assessing their impact on embryo survival rate.
Measured: Throughout the study period, approximately 4 years.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Dec 2024
- Study start1 Sep 2025 (estimated)
- Primary completion31 Oct 2026 (estimated)
- Study completion31 Oct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (11)Papers the sponsor has linked to this study.
- Other trials for Frozen Embryo Transfer (FET)Studies of the same condition, open and under way.
- More trials run by Chinese University of Hong KongThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study uses a parallel assignment model where participants are randomized into two groups: one group will receive the novel direct warming method, and the other group will undergo the conventional multi-step thawing method. Both groups will be followed to compare clinical outcomes such as pregnancy rates, live birth rates, and cost-effectiveness.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 578 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Chinese University of Hong Kong
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Yiu Leung David Chan, Chinese University of Hong Kong
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06741748
- Sponsor's protocol ID
- 2024.132-T
- Acronym
- DW-FET-RCT
- Status last verified
- Mar 2025
- First submitted
- 19 Nov 2024
- Last updated
- 11 Mar 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: IPD will not be shared due to concerns regarding participant confidentiality and privacy. Additionally, the informed consent process did not include provisions for the sharing of individual-level data with third parties. Furthermore, local regulatory restrictions limit the ability to distribute sensitive health data outside the study team.
Publications
Canosa S, Parmegiani L, Charrier L, Gennarelli G, Garello C, Granella F, Evangelista F, Monelli G, Guidetti D, Revelli A, Filicori M, Bongioanni F. Are commercial warming kits interchangeable for vitrified human blastocysts? Further evidence for the adoption of a Universal Warming protocol. J Assist Reprod Genet. 2022 Jan;39(1):67-73. doi: 10.1007/s10815-021-02364-1. Epub 2021 Nov 30.
PubMed 34845576Wang SF, Seifer DB. Age-related increase in live-birth rates of first frozen thaw embryo versus first fresh transfer in initial assisted reproductive technology cycles without PGT. Reprod Biol Endocrinol. 2024 Apr 13;22(1):42. doi: 10.1186/s12958-024-01210-0.
PubMed 38615016Parmegiani L, Beilby KH, Arnone A, Bernardi S, Maccarini AM, Nardi E, Cognigni GE, Filicori M. Testing the efficacy and efficiency of a single "universal warming protocol" for vitrified human embryos: prospective randomized controlled trial and retrospective longitudinal cohort study. J Assist Reprod Genet. 2018 Oct;35(10):1887-1895. doi: 10.1007/s10815-018-1276-4. Epub 2018 Aug 3.
PubMed 30074129Schiewe MC, Anderson RE. Vitrification: the pioneering past to current trends and perspectives of cryopreserving human embryos, gametes and reproductive tissue. Journal of Biorepository Science for Applied Medicine. 2017;5:57-68.
Jiang VS, Cherouveim P, Naert MN, Dimitriadis I, Souter I, Bormann CL. Live birth outcomes following single-step blastocyst warming technique - optimizing efficiency without impacting live birth rates. J Assist Reprod Genet. 2024 May;41(5):1193-1202. doi: 10.1007/s10815-024-03069-x. Epub 2024 Mar 13.
PubMed 38472563Liebermann J, Hrvojevic K, Hirshfeld-Cytron J, Brohammer R, Wagner Y, Susralski A, Jasulaitis S, Chan S, Takhsh E, Uhler M. Fast and furious: pregnancy outcome with one-step rehydration in the warming protocol for human blastocysts. Reprod Biomed Online. 2024 Apr;48(4):103731. doi: 10.1016/j.rbmo.2023.103731. Epub 2023 Nov 23.
PubMed 38359734Manns JN, Katz S, Whelan J, Patrick JL, Holt T, Merline AM, et al. VALIDATION OF A NEW, ULTRA-FAST BLASTOCYST WARMING TECHNIQUE REDUCES WARMING TIMES TO 1 MIN AND YIELDS SIMILAR SURVIVAL AND RE-EXPANSION COMPARED TO BLASTOCYSTS WARMED USING A STANDARD METHOD. Fertility and Sterility.
Yan G, Yao Y, Yang W, Lu L, Wang L, Zhao D, Zhao S. An all-37 degrees C thawing method improves the clinical outcomes of vitrified frozen-thawed embryo transfer: a retrospective study using a case-control matching analysis. Arch Gynecol Obstet. 2023 Jun;307(6):1991-1999. doi: 10.1007/s00404-023-07029-1. Epub 2023 Apr 12.
PubMed 37041370Rienzi 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.
PubMed 27827818Trounson A, Mohr L. Human pregnancy following cryopreservation, thawing and transfer of an eight-cell embryo. Nature. 1983 Oct 20-26;305(5936):707-9. doi: 10.1038/305707a0.
PubMed 6633637Wu W, Xu M, Fung KK, Zhang L, Wan HM, Chan CPS, Chung JPW, Chan DYL. Direct warming and rehydration method in frozen embryo transfer: study protocol for a pragmatic, multi-center, double-blinded, two-arm randomized controlled trial. Trials. 2026 May 18;27(1):480. doi: 10.1186/s13063-026-09663-x.
PubMed 42152121
Study at a glance
From the registry record, last updated by the sponsor on 11 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Pragmatic, Multi-centre, Double-blinded, Two-arm Randomized Controlled Trial on a Direct Warming Frozen Embryo Transfer in Assisted Reproductive Technologies Treatment Outcome
- ClinicalTrials.gov ID
- NCT06741748
- Acronym / sponsor ID
- DW-FET-RCT / 2024.132-T
- Conditions
- Frozen Embryo Transfer (FET), Assisted Reproductive Techniques, In Vitro Fertilization (IVF), Cryopreservation of Embryos, Pregnancy Outcome After in Vitro Fertilization (IVF)
- Keywords
- Direct Warming Method, Frozen Embryo Transfer, Assisted Reproductive Technologies, Cryopreservation, Cost-effectiveness in ART, Embryo Warming, In Vitro Fertilization
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 578 participants (estimated)
- Lead sponsor
- Chinese University of Hong KongUniversity, hospital or other
- Study start
- 1 Sep 2025 (estimated)
- Primary completion
- 31 Oct 2026 (estimated)
- Study completion
- 31 Oct 2027 (estimated)
- First posted
- 19 Dec 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to evaluate whether the direct warming method for frozen embryo transfers (FET) can improve live birth and pregnancy outcomes in women aged 18-45 undergoing IVF treatments. The main questions it aims to answer are:
- Does the direct warming method achieve a similar or higher clinical success rate for FET compared to the conventional multi-step method?
- Is the direct warming method more cost-effective than the conventional method?
Researchers will compare the direct warming method to the conventional multi-step method to see if the former leads to better pregnancy outcomes and reduced procedural time.
Participants will:
- Undergo either the one-step or conventional embryo thawing procedure.
- Complete standard clinical follow-ups for pregnancy, including ultrasound scans and pregnancy tests.
Detailed description
This clinical trial explores a novel direct warming method for frozen embryo transfer (FET), aimed at improving both clinical and operational outcomes in assisted reproductive technologies (ART). The method was designed to simplify and accelerate the embryo thawing process, reducing the time needed for thawing while eliminating the use of cryoprotectants commonly required in conventional thawing methods. This innovation has the potential to offer a more efficient and cost-effective alternative to standard FET procedures.
The primary focus of this trial is to compare the clinical effectiveness of the direct warming method against the conventional multi-step thawing process. In particular, the study seeks to determine whether the new method yields comparable or superior outcomes in terms of clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), and live birth rate (LBR), while also assessing its overall cost-effectiveness.
Study Design and Technical Details
This study employs a randomized controlled design, with participants being allocated into either the intervention group (direct warming method) or the control group (conventional multi-step thawing). The direct warming method streamlines the thawing process to just 3 minutes, in contrast to the conventional method, which requires multiple stages and takes approximately 20 minutes. By using only an embryo culture medium without cryoprotectants, the direct warming method reduces both complexity and potential risks associated with handling and cryoprotectant toxicity.
Key Objectives
- Primary Objective: To evaluate the clinical efficacy of the direct warming method in achieving comparable or higher success rates for FET as compared to conventional multi-step thawing.
- Secondary Objective: To assess the cost-effectiveness of the direct warming method by comparing the consumable and time costs across different centers.
Expected Impact and Innovation
The direct warming method challenges the traditional multi-step thawing approach, offering a faster and simpler alternative without compromising clinical outcomes. By minimizing the need for cryoprotectants and reducing the complexity of the thawing process, the new method is expected to enhance the overall efficiency of FET procedures while maintaining or improving pregnancy success rates. Additionally, the cost and time savings associated with the direct warming method may make it a viable option for IVF clinics worldwide, driving standardization and consistency across clinical settings.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- This study uses a parallel assignment model where participants are randomized into two groups: one group will receive the novel direct warming method, and the other group will undergo the conventional multi-step thawing method. Both groups will be followed to compare clinical outcomes such as pregnancy rates, live birth rates, and cost-effectiveness.
| Arm | Type | Receives |
|---|---|---|
| Direct Warming method | Experimental | Other: Direct Warming MethodThe blastocyst designated for thawing will be placed in a pre-warmed, direct warming medium for one minute. Afterward, the embryo is transferred into an embryo culture medium within a time-lapse system, where it remains until the patient is ready for the embryo transfer procedure. This direct warming method significantly reduces the total procedure time to approximately 3 minutes, making it about ten times faster than the conventional multi-step thawing method. |
| Conventional multi-step thawing method | Placebo comparator | Other: Conventional Multi-step Thawing MethodIn the conventional multi-step thawing method, vitrified blastocysts are sequentially thawed using a series of pre-warmed thawing, dilution, and washing solutions. The blastocyst is first placed in a thawing solution for 1-3 minutes, followed by immersion in a dilution solution for 4-6 minutes to reduce cryoprotectant concentration. Finally, the blastocyst is transferred to a washing solution for 5-10 minutes for rehydration. The entire process takes approximately 30 minutes, after which the embryo is placed into an embryo culture medium in a time-lapse system until it is ready for embryo transfer. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Plan to undergo single embryo transfer (SET) during the FET cycle.
- Age between 18 and 45 years.
- Patients with at least one high-quality blastocyst available for transfer.
- Patients who have provided informed consent to participate in the study.
Key exclusion criteria (3 listed)
- Patients with repeated implantation failure (RIF) or recurrent miscarriage (RM).
- Patients with known uterine anomalies or significant uterine pathology (e.g., fibroids, polyps).
- Patients who are unwilling or unable to provide informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Direct Warming MethodAlso: One-step thawingThis intervention involves thawing vitrified blastocysts using a simplified, one-step direct warming method. The blastocyst is placed in a pre-warmed embryo culture medium for approximately one minute, then transferred directly into the embryo culture medium within a time-lapse system until ready for uterine transfer. The total thawing process takes approximately three minutes, reducing the duration and complexity of the procedure compared to conventional methods. | Other | Direct Warming method |
| Conventional Multi-step Thawing MethodThis intervention involves thawing vitrified blastocysts using a standard, multi-step process. The procedure includes sequential exposure of the blastocyst to different thawing solutions containing varying concentrations of cryoprotectants, followed by its transfer into an embryo culture medium in a time-lapse system. The overall process takes approximately 10-30 minutes. | Other | Conventional multi-step thawing method |
Primary outcome
Clinical Pregnancy Rate
Time frame: 6-8 weeks post embryo transfer
Number of participants with at least one intrauterine gestational sac observed on ultrasound at 6-8 weeks of gestation following embryo transfer.
Ongoing Pregnancy Rate (OPR)
Time frame: 12 weeks post embryo transfer
Number of participants with a viable intrauterine pregnancy observed on ultrasound at 12 weeks of gestation.
Live Birth Rate (LBR)
Time frame: At delivery, approximately 9 months post embryo transfer
Number of participants who deliver a live infant after 24 weeks of gestation.
Cost-Effectiveness
Time frame: At the end of the study, approximately 4 years.
A comparative analysis of the total costs, including costs of consumables (e.g., warming mediums, storage devices) and staff labor hours, associated with the direct warming method compared to the conventional multi-step thawing method. Costs will be measured in USD and analyzed at the end of the study period.
2 secondary outcomes
Subgroup Analysis of Warming Medium
Time frame: Throughout the study period, approximately 4 years.
Subgroup Analysis of Storage Devices
Time frame: Throughout the study period, approximately 4 years.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Mar 2025.
- Background: PubMed 34845576Canosa S, Parmegiani L, Charrier L, Gennarelli G, Garello C, Granella F, Evangelista F, Monelli G, Guidetti D, Revelli A, Filicori M, Bongioanni F. Are commercial warming kits interchangeable for vitrified human blastocysts? Further evidence for the adoption of a Universal Warming protocol. J Assist Reprod Genet. 2022 Jan;39(1):67-73. doi: 10.1007/s10815-021-02364-1. Epub 2021 Nov 30.
- Background: PubMed 38615016Wang SF, Seifer DB. Age-related increase in live-birth rates of first frozen thaw embryo versus first fresh transfer in initial assisted reproductive technology cycles without PGT. Reprod Biol Endocrinol. 2024 Apr 13;22(1):42. doi: 10.1186/s12958-024-01210-0.
- Background: PubMed 30074129Parmegiani L, Beilby KH, Arnone A, Bernardi S, Maccarini AM, Nardi E, Cognigni GE, Filicori M. Testing the efficacy and efficiency of a single "universal warming protocol" for vitrified human embryos: prospective randomized controlled trial and retrospective longitudinal cohort study. J Assist Reprod Genet. 2018 Oct;35(10):1887-1895. doi: 10.1007/s10815-018-1276-4. Epub 2018 Aug 3.
- BackgroundSchiewe MC, Anderson RE. Vitrification: the pioneering past to current trends and perspectives of cryopreserving human embryos, gametes and reproductive tissue. Journal of Biorepository Science for Applied Medicine. 2017;5:57-68.
- Background: PubMed 38472563Jiang VS, Cherouveim P, Naert MN, Dimitriadis I, Souter I, Bormann CL. Live birth outcomes following single-step blastocyst warming technique - optimizing efficiency without impacting live birth rates. J Assist Reprod Genet. 2024 May;41(5):1193-1202. doi: 10.1007/s10815-024-03069-x. Epub 2024 Mar 13.
- Background: PubMed 38359734Liebermann J, Hrvojevic K, Hirshfeld-Cytron J, Brohammer R, Wagner Y, Susralski A, Jasulaitis S, Chan S, Takhsh E, Uhler M. Fast and furious: pregnancy outcome with one-step rehydration in the warming protocol for human blastocysts. Reprod Biomed Online. 2024 Apr;48(4):103731. doi: 10.1016/j.rbmo.2023.103731. Epub 2023 Nov 23.
- BackgroundManns JN, Katz S, Whelan J, Patrick JL, Holt T, Merline AM, et al. VALIDATION OF A NEW, ULTRA-FAST BLASTOCYST WARMING TECHNIQUE REDUCES WARMING TIMES TO 1 MIN AND YIELDS SIMILAR SURVIVAL AND RE-EXPANSION COMPARED TO BLASTOCYSTS WARMED USING A STANDARD METHOD. Fertility and Sterility.
- Background: PubMed 37041370Yan G, Yao Y, Yang W, Lu L, Wang L, Zhao D, Zhao S. An all-37 degrees C thawing method improves the clinical outcomes of vitrified frozen-thawed embryo transfer: a retrospective study using a case-control matching analysis. Arch Gynecol Obstet. 2023 Jun;307(6):1991-1999. doi: 10.1007/s00404-023-07029-1. Epub 2023 Apr 12.
- Background: PubMed 27827818Rienzi 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.
- Background: PubMed 6633637Trounson A, Mohr L. Human pregnancy following cryopreservation, thawing and transfer of an eight-cell embryo. Nature. 1983 Oct 20-26;305(5936):707-9. doi: 10.1038/305707a0.
- Derived from this study: PubMed 42152121Wu W, Xu M, Fung KK, Zhang L, Wan HM, Chan CPS, Chung JPW, Chan DYL. Direct warming and rehydration method in frozen embryo transfer: study protocol for a pragmatic, multi-center, double-blinded, two-arm randomized controlled trial. Trials. 2026 May 18;27(1):480. doi: 10.1186/s13063-026-09663-x.
- Individual participant dataSharing planned: Undecided. IPD will not be shared due to concerns regarding participant confidentiality and privacy. Additionally, the informed consent process did not include provisions for the sharing of individual-level data with third parties. Furthermore, local regulatory restrictions limit the ability to distribute sensitive health data outside the study team.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
3 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Direct Warming Method and Conventional Multi-step Thawing Method in people with Frozen Embryo Transfer (FET) and Assisted Reproductive Techniques, run by Chinese University of Hong Kong at 3 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 11 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Hong Kong, United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Yiu Leung D Chan, DPhil ((852) 3505 3199, drdcyl16@cuhk.edu.hk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Clinical Pregnancy Rate (time frame: 6-8 weeks post embryo transfer). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06741748, which also lists 11 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Mar 2025.