The international transportation of frozen embryos does not affect IVF outcomes

The regulated transportation of cryopreserved human embryos resulting from assisted reproduction treatments offers opportunities for patients undergoing embryo transfer in other regions/countries. However, the principal concern for fertility clinics is maintaining unaltered embryo quality to ensure satisfactory clinical outcomes. The aim of the study was to evaluate the efficacy of the transportation process comparing the survival rate and competence of transported embryos to embryos produced and transferred on-site, in frozen embryo transfer cycles.

This retrospective study assessed the outcomes of 621 blastocysts thawed at IVI Roma (Italy) between March 2021 and March 2022. Autologous or donated oocytes fertilized in vitro, cultured to the blastocyst stage, and cryopreserved in IVI Roma clinic (Group A, n = 450), were compared to embryos generated in IVI Spain clinics and transported to IVI Roma (Group B, n = 171).

Groups A and B respectively showed no significant difference in embryo survival rates after thawing (N = 440/450, 97.8% vs. N = 168/171, 98.2%, p = 0.71), pregnancy rates (N = 221/440, 50.23% vs. N = 77/168, 45.83%, p = 0.33), clinical pregnancy rates (N = 200/440, 45.45% vs. N = 62/168, 36.90%, p = 0.06), and miscarriage rates (N = 42/221, 19,00% vs. 21/77, 28.57%, p = 0.13), even after stratification for the source of the oocyte. Logistic binomial regression considering donor oocytes, preimplantation genetic testing, and patients' age, did not show any significant results on embryo survival and IVF outcomes.

The regulated transport of cryopreserved blastocysts did not affect embryo survival rate or IVF outcomes. Our data support the safety of embryo cryopreservation and medical transportation services, allowing clinics and patients to transport embryos with no significant risk to embryo competence.