The success of a frozen blastocyst transfer cycle is predicted by the outcome of the corresponding fresh blastocyst transfer cycle

Abstract

To analyze the clinical pregnancy rates (CPR) and live birth rates (LBR) per transfer in frozen blastocyst transfer (frozen-BT) cycles relative to the outcome of the fresh blastocyst transfer (fresh-BT) cycle from the same cohort of embryos. Retrospective analysis. Patients who had undergone both fresh and frozen blastocyst transfer cycles using blastocysts of the same cohort were identified. CPR and LBR were compared in frozen-BT cycles (n=125) subsequent to fresh-BT cycles which did or did not result in clinical pregnancy or live birth, respectively. Patient and cycle characteristics were compared in each subgroup. Statistical analysis was performed with the chi-square test and student's t-test for categorical and continuous variables, respectively. All subgroups had similar baseline characteristics, numbers of oocytes retrieved, fresh blastocysts transferred, blastocysts cryopreserved, and frozen blastocysts transferred. Overall, CPR and LBR in fresh-BT cycles were 44% and 29%, and were 34% and 30% in frozen-BT, respectively. Frozen-BT cycle CPR were significantly higher in patients who were not pregnant in fresh-BT cycles compared to patients who were pregnant (43% vs. 22%, P=0.01). Similarly, frozen-BT LBR were significantly higher in patients who did not achieve live birth in fresh-BT cycles compared to patients who did (36% vs. 17%, P=0.03). When counseling patients on whether to utilize cryopreserved blastocysts or start another fresh cycle, it is important to consider the fresh cycle outcome. If the fresh cycle was unsuccessful, the remaining frozen blastocysts have the same chances of success as the fresh cycle. However, frozen BT cycles following successful fresh BT cycles have significantly lower CPR and LBR, justifying the consideration of a new fresh cycle. These data further support the evidence that few embryos per cohort are competent to produce a live birth.