EC Gynaecology

Systematic Review Volume 14 Issue 9 - 2025

Comparative Effectiveness of Cryopreserved and Fresh Oocyte Strategies in Donor IVF Cycles. Systematic Review and Meta-Analysis

Francesco Maria Bulletti1, Maurizio Guido2, Maria Elisabetta Coccia3, Antonio Palagiano4, Evaldo Giacomucci5, Francesco Maria Bracco6 and Carlo Bulletti7*

1Maternity and Gynaecology Department, CHUV, Avenue Pierre Decker 2, Lausanne, Switzerland

2Full Professor of Obstetrics and Gynaecology, University of Calabria, Cosenza, Italy

3Associate Professor, Department of Biomedical, Experimental and Clinical Sciences “Mario Serio”, University of Florence, AOU Careggi, Italy

4Senior Consultant, Fertility and Sterility Centre CFA (Centro Fecondazione Assistita) Naples, Italy

5Head, Obstetrics and Gynaecology Unit, Ospedale Maggiore, Bologna, Italy

6Resident in Division of Urology, Department of Oncology, Molinette Hospital, University of Torino, School of Medicine, Turin, Italy

7Adjunct Associate Professor, Department of Obstetrics, Gynaecology and Reproductive Sciences, Yale University, New Haven, CT and Director, Help Me Doctor (Global Second Opinion Platform), USA

*Corresponding Author: Carlo Bulletti, Adjunct Associate Professor, Department of Obstetrics, Gynaecology and Reproductive Sciences, Yale University, New Haven, CT and Director, Help Me Doctor (Global Second Opinion Platform), USA.
Received: July 28, 2025; Published: September 08, 2025



Objective: To evaluate and compare pregnancy and live birth outcomes across four distinct assisted reproductive technology (ART) strategies using donor oocytes, with a specific focus on the timing of cryopreservation, fertilization, and embryo transfer.

Design: Systematic review and meta-analysis following PRISMA 2020 guidelines.

Setting: Global data extraction from ART registries (SART, CDC, HFEA, ESHRE) and peer-reviewed comparative studies published between 2015 and 2025.

Patients: Couples undergoing IVF with donor oocytes, stratified by age group and protocol arm.

Interventions: Four clinical arms were compared:

  • Arm 1: Cryopreserved donor oocytes transported to recipient centers for in-loco fertilization and transfer.
  • Arm 2: Fresh donor oocytes fertilized with cryopreserved sperm at the donor site; embryos cultured to blastocyst stage, cryopreserved, and shipped.
  • Arm 3: Double cryopreservation of oocytes and sperm prior to fertilization; thawed, fertilized, re-cryopreserved, and transferred to recipient centers.
  • Arm 4: Fresh oocyte and sperm fertilization with immediate blastocyst transfer.

Main Outcome Measures: Live birth rate (LBR), clinical pregnancy rate (CPR), and implantation rate (IR), stratified by maternal age and protocol arm.

Results: Arm 4 consistently demonstrated the highest live birth rate (LBR 48.1%) and pregnancy rates (CPR 56.4%), particularly in recipients < 38 years. Arm 3 showed significantly lower outcomes (LBR 30.2%, CPR 38.9%), associated with repeated thaw cycles. Risk of bias was lowest in Arm 4 studies and highest in Arm 3. GRADE certainty was moderate to high for Arms 1, 2, and 4, but downgraded in Arm 3 due to confounding and reporting limitations.

Conclusion: Protocols involving fresh gametes and direct transfer offer superior reproductive outcomes and lower bias. Strategies employing multiple cryopreservation events (Arm 3) may compromise efficacy. Clinical and policy decisions should balance resource efficiency with evidence-based outcomes and patient-centered care.

 Keywords: Donor Oocyte; IVF; Cryopreservation; Embryo Transfer; Thaw-Refreeze; Live Birth Rate; Systematic Review; Meta-Analysis; PRISMA

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Carlo Bulletti., et al. “Comparative Effectiveness of Cryopreserved and Fresh Oocyte Strategies in Donor IVF Cycles. Systematic Review and Meta-Analysis”. EC Gynaecology  14.9 (2025): 01-26.

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