Two sequential vitrification/warming events at 2PN stage and blastocyst stage is compatible with good clinical outcome

Objectives The objective of the study is evaluate the reproductive potential of embryos after two cryopreservation events at different developmental stages (PN and blastocyst stage; twice-cryopreserved group, TC) compared to once-cryopreserved (OC) blastocysts.

Materials and methods A single center, retrospective data analysis was carried out for the time period of 2015-2020. From a total of 2,212 initiated frozen-embryo transfer (FET) cycles, FET cycles after TC and after OC were retrieved. Cycles with preimplantation genetic testing or oocyte freezing were excluded.

Results A total of 182 FETs were carried out in the TC group, originating from 134 fresh cycles of 122 patients. In the OC group, 288 FETs from 218 fresh cycles of 210 patients were identified. Mean female age, BMI and the number of embryos transferred were similar between the two groups. The number of retrieved oocytes was significantly higher in the TC group compared to the OC group.

Twice-cryopreserved embryo transfers resulted in 46.2% [95%CI: 38.9-53.4] positive hCG, 23.1% [95%CI: 16.9-29.2] clinical and 20.9% [95%CI: 14.9-26.8] live birth rates per FET. In the OC group, 46.9% [95%CI: 41.1-52.6]) positive hCG, 30.6% [95%CI: 24.5-36.6] clinical and 27.1% [95%CI: 21.9-32.2] live birth rate per FET was found. The unadjusted difference for live birth is -6.2% [95% CI: -14.1-1.6].

Summary The accumulation of outcome data from circumstantial use of sequential double vitrification/warming indicates that double cryopreservation is compatible with acceptably good clinical outcome. This may help clinicians advise patients and offer this as a valid alternative.

Publikationsverlauf

Artikel online veröffentlicht:
11. Oktober 2022