Outcomes of blastocysts biopsied and vitrified once versus those cryopreserved twice for euploid blastocyst transfer

Trophectoderm biopsy with comprehensive chromosome screening (CCS) has been shown to increase implantation and pregnancy rates. Some patients desire CCS on previously cryopreserved blastocysts, resulting in blastocysts that are thawed/warmed, biopsied, vitrified and then warmed again. The effect of two cryopreservation procedures and two thawing/warming procedures on outcomes has not been effectively studied. Cycles were divided into two groups: group 1 patients underwent a cryopreserved embryo transfer with euploid blastocysts that were vitrified and warmed once; group 2 patients had a cryopreserved embryo transfer of a euploid blastocyst that was cryopreserved, thawed/warmed, biopsied, vitrified and warmed. Groups 1 and 2 included 85 and 17 women aged 35.6 +/- 3.9 and 35.3 +/- 4.9 years, respectively (not significantly different). Blastocyst survival in group 1 (114/116, 98.3%) and survival of second warming in group 2 (21/24, 87.5%) was significantly different (P = 0.0354). There was no difference between biochemical (68.2% and 62.5%) and clinical (61.2% and 56.3%) pregnancy rates, implantation rate (58.4% and 52.4%) and live birth/ongoing pregnancy rate (54.0% and 47.6%) between groups 1 and 2, respectively. Although it is unconventional to thaw/warm, biopsy, revitrify and rewarm blastocysts for cryopreserved embryo transfer, the results indicate that outcomes are not compromised. (C) 2014, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.