Impact of having surplus blastocysts cryopreserved on the ongoing pregnancy rate following a fresh transfer

This study aimed to investigate whether a surplus of vitrified blastocysts correlated with ongoing pregnancy by analyzing the clinical outcomes of fresh transfer cycles with/without a surplus of vitrified blastocysts. This was a retrospective analysis carried out in the Reproductive Medicine Center of Guizhou Medical University Affiliated Hospital between January 2020 and December 2021. Overall, 2482 fresh embryo transfer cycles were included in this study, including 1731 cycles with a surplus of vitrified blastocysts (group A) and 751 cycles with no surplus of vitrified blastocysts (group B). The clinical outcomes of fresh embryo transfer cycles were analyzed and compared between the two groups. In total, the clinical pregnancy rate (CPR) and ongoing pregnancy rate (OPR) after fresh transfer in group A were significantly higher than those in group B (59% vs. 34.1%, p