Single-step versus multi-step blastocyst warming for frozen embryo transfer
The Live Birth Rate Between Single and Multi-step Warming Protocol Applied in Blastocyst Vitrification: a Randomized Controlled Trial
This tests whether a simpler single-step thawing solution works as well or better than the standard multi-step warming for women having frozen blastocyst transfers.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 816 (estimated) |
| Ages | 18 Years and up |
| Sex | Female |
| Sponsor | Mỹ Đức Hospital Academic / other |
| Locations | 1 site (Ho Chi Minh City, City) |
| Trial ID | NCT07088640 on ClinicalTrials.gov |
What this trial studies
Vitrified blastocysts are typically warmed with a multi-step protocol that gradually reduces cryoprotectant concentration to avoid osmotic shock; this study compares that standard method with a simplified single-step thawing solution. Eligible women will have at least one good-quality frozen blastocyst, undergo endometrial preparation with an artificial cycle, and agree to a single blastocyst transfer. Participants will receive either the single-step warming protocol or the standard multi-step protocol and embryologists will record embryo survival, implantation and pregnancy outcomes as well as laboratory time and workflow metrics. The design is informed by prior reports suggesting warming rate is a key determinant of survival and by studies showing comparable survival and pregnancy outcomes using simplified warming approaches.
Who should consider this trial
Good fit: Women aged 18 or older with at least one good-quality vitrified blastocyst, no more than three prior IVF/ICSI cycles, planning an artificial-cycle single blastocyst transfer, and not enrolled in other interventional studies.
Not a fit: Patients whose embryos came from in‑vitro maturation cycles, underwent preimplantation genetic testing, have contraindications to exogenous hormones, or have significant uterine abnormalities are excluded and unlikely to benefit from this protocol.
Why it matters
Potential benefit: If successful, the simpler thawing method could shorten lab time, reduce embryologist workload, and possibly improve pregnancy rates for patients using frozen blastocysts.
How similar studies have performed: Previous studies have reported comparable embryo survival and in some reports higher pregnancy rates with simplified warming protocols, and laboratory research shows warming rate strongly influences survival.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Women aged from 18 * Undergoing no more than 3 previous IVF/ICSI cycles * Had at least a single good-quality blastocyst frozen. * Endometrium preparation using artificial cycle * Agree to single blastocyst transfer * Not participating in any interventional studies at the same time Exclusion Criteria: * Embryos from cycles after in-vitro maturation, pre-implantation genetic testing (PGT) * Having contraindications for exogenous hormone administration (e.g., breast cancer, thromboembolic disease) * Having uterine abnormalities (e.g., adenomyosis, intrauterine adhesions, unicornuate/ bicornuate/ arcuate uterus; unremoved hydrosalpinx or endometrial polyp)
Where this trial is running
Ho Chi Minh City, City
- My Duc Hospital — Ho Chi Minh City, City, Vietnam (Recruiting)
Study contacts
- Principal investigator: Lan TN Vuong, MD, PhD — University of Medicine and Pharmacy at Ho Chi Minh City
- Study coordinator: Tam TM Luu, MD
- Email: tam.ltm@myduchospital.vn
- Phone: +84357426024
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.