A retrospective study of single frozen-thawed blastocyst transfer

Abstract

ObjectiveTo study the clinical outcomes of single frozen-thawed blastocyst transfer cycles according to the hatching status of frozen-thawed blastocysts.MethodsFrozen-thawed blastocysts were divided into three groups according to their hatching status as follows: less-than-expanded blastocyst (≤EdB), hatching blastocyst (HgB), and hatched blastocyst (HdB). The female age and infertility factors of each group were evaluated. The quality of the single frozen-thawed blastocyst was also graded as grade A, tightly packed inner cell mass (ICM) and many cells organized in the trophectoderm epithelium (TE); grade B, several and loose ICM and TE; and grade C, very few ICM and a few cells in the TE. The clinical pregnancy and implantation rate were compared between each group. The data were analyzed by either t-test or chi-square analysis.ResultsThere were no statistically significant differences in average female ages, infertility factors, or the distribution of blastocyst grades A, B, and C in each group. There was no significant difference in the clinical pregnancy and implantation rate of each group according to their blastocyst grade. However, there was a significant difference in the clinical pregnancy and implantation rate between each group. In the HdB group, the clinical pregnancy and implantation rate were similar regardless of the blastocyst quality.ConclusionThere was an effect on the clinical outcomes depending on whether the blastocyst hatched during single frozen-thawed blastocyst transfer. When performing single frozen-thawed blastocyst transfer, the hatching status of the frozen-thawed blastocyst may be a more important parameter for clinical outcomes than the quality of the frozen-thawed blastocyst.

Pregnancy rates for single embryo transfer (SET) of day 5 and day 6 blastocysts after cryopreservation by vitrification and slow freeze

“…All frozen embryos considered for transfer in this study were of good quality despite delayed blastulation in the day 6 cryopreservation group, and therefore, our decision to continue to recommend SET is based on previous literature. Previous studies suggest morphologic grading, and evaluation at the time of vitrification and post-thaw may be more important than time passed in vitro and rate of development [19,[28][29][30][31][32]. Furthermore, hatching status may be even more indicative of clinical outcome than grading [32].…”

“…Previous studies suggest morphologic grading, and evaluation at the time of vitrification and post-thaw may be more important than time passed in vitro and rate of development [19,[28][29][30][31][32]. Furthermore, hatching status may be even more indicative of clinical outcome than grading [32]. When available, the use of preimplantation genetic screening has been added to the assessment and selection of the embryo.…”

Laser‐assisted hatching on clinical and neonatal outcomes in patients undergoing single vitrified Blastocyst transfer: A propensity score–matched study

“…The current study suggests that 83.4% of LAH blastocysts completely escaped from the ZP after overnight culture and improved the CPR and LBR compared with the control group. Extending the culture of vitrified blastocysts would be helpful for measuring embryonic development and improving CPR and LBR 26 . Also, these did not affect either the clinical or neonatal outcomes in the current study.…”

Associations of post-warming embryo or blastocyst development with clinical pregnancy in vitrified embryo or blastocyst transfer cycles

“…In transfer cycles involving euploid blastocysts, pre-freezing inner cell mass morphology affected implantation and ongoing pregnancy rates [10]. In a study of single frozen blastocyst transfer cycles, Hur et al [11] found that the clinical pregnancy/implantation rate depended on whether the transferred blastocyst was hatched, but was not associated with the blastocyst grade. In cryopreserved embryo or blastocyst transfer cycles, embryos or blastocysts are usually thawed or warmed in the evening of the day before transfer; thus, embryos or blastocysts usually develop spontaneously until transfer.…”