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NCT Number: NCT06741748

Direct Warming Frozen Embryo Transfer Outcomes in Assisted Reproductive Technology

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.

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Key information

Conditions

Frozen Embryo Transfer (FET) Assisted Reproductive Techniques Cryopreservation of Embryos In Vitro Fertilization (IVF) Pregnancy Outcome After in Vitro Fertilization (IVF)

Age range

18 year–45 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, Hong Kong

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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.

Treatment and study plan

Direct Warming Method

Other

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.

Other names: One-step thawing

Conventional Multi-step Thawing Method

Other

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.

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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.

Secondary outcomes

  1. Subgroup Analysis of Warming Medium

    Time frame: Throughout the study period, approximately 4 years.

    Analysis of the clinical differences between brands of warming mediums assessing their impact on embryo survival rate.

  2. Subgroup Analysis of Storage Devices

    Time frame: Throughout the study period, approximately 4 years.

    Analysis of the clinical differences between brands of Storage Devices assessing their impact on embryo survival rate.

Study contacts

Contact information is provided by the study sponsor or research team.

Waner Wu, MPhil

CONTACT

[email protected]

(852) 3505 1764

Yiu Leung D Chan, DPhil

CONTACT

[email protected]

(852) 3505 3199

Sponsors and collaborators

Lead sponsor

Chinese University of Hong Kong

Other

Registry information

Official study 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

Acronym: DW-FET-RCT

Important dates

Study start
2025
Primary completion
2026
Study completion
2027
First posted
Dec 19, 2024
Registry last updated
Mar 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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