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Fresh Versus Vitrified-Warmed Donor Oocytes: Embryological and Clinical Outcomes
Sponsor: Center for Reproductive Medicine Bocian
Summary
This multicenter retrospective observational study compares embryological and clinical outcomes following treatment with fresh versus vitrified-warmed donor oocytes at Bocian Fertility Clinic centers in Poland. The study focuses on a standardized allocation strategy in which recipients are intended to receive six mature (metaphase II, MII) donor oocytes. In the vitrified-warmed group, oocytes are cryopreserved at the MII stage and subsequently warmed for use. Oocytes lost during warming are not routinely replaced, allowing the study to evaluate the consequences of warming-related losses within the initial allocation. The study will assess fertilization, embryo development, usable blastocyst yield, the probability of obtaining an embryo for transfer, and live birth following the first embryo transfer originating from the allocated oocytes. Clinical effectiveness will be evaluated from the initial oocyte allocation, including cycles in which no embryo transfer occurs. The objective is to determine whether fresh and vitrified-warmed donor-oocyte strategies are associated with differences in embryological efficiency and the likelihood of live birth when the initial number of mature allocated oocytes is standardized.
Official title: From Six Allocated Mature Donor Oocytes to Live Birth: A Multicenter Retrospective Cohort Study Comparing Fresh and Vitrified-Warmed Oocyte Donation Strategies
Key Details
Gender
FEMALE
Age Range
18 Years - Any
Study Type
OBSERVATIONAL
Enrollment
3000
Start Date
2026-03-01
Completion Date
2028-06
Last Updated
2026-10-29
Healthy Volunteers
No
Interventions
Fresh Donor Oocyte ICSI
Recipients underwent routine ICSI using fresh mature donor oocytes. Under the standard allocation strategy, six MII oocytes were allocated to each recipient. No treatment procedures were assigned or modified for research purposes.
Vitrified-Warmed Donor Oocyte ICSI
Recipients underwent routine ICSI using donor oocytes previously vitrified at the MII stage. Six vitrified MII oocytes were allocated for warming. Oocytes lost during warming were not routinely replaced. No treatment procedures were assigned or modified for research purposes.
Locations (1)
Bocian Fertility Clinic
Szczecin, West Pomeranian Voivodeship, Poland