Evaluation of the Clinical Efficacy of Vitrification, Warming and Blastocyst Transplantation in Assisted Reproductive Treatment.

Background and Objective: Advances in cell media have led to embryo transfer from cleavage to blastocyst. The extension of embryo culture to blastocyst stage provides some theoretical advantages and disadvantages that have been controversial. The objective of this study was to evaluate the clinical efficacy of vitrified warm cutting and blastocyst transplantation in Assisted Reproductive Technique (ART) therapy. Methods: The study was performed on 2740 women undergoing frozen embryo thawing transfer. Patients' basic clinical information, status of frozen embryo transfer cycle, clinical pregnancy rate, early abortion rate, sex ratio of birth and birth weight were retrospectively analyzed. The main clinical outcomes of the recovery of frozen embryos at cleavage and blastocyst stages were compared. In addition, the clinical outcomes of blastocyst cryopreservation on the 5th, 6th or 7th day after oocyte retrieval according to the date of blastocyst expansion were recorded. Results: The implantation ratio of cleavage stage embryos was 21.62% compared with 43.52% on D5 (P < 0.05). The D5, D6, and D7 implanting rates were statistically different. The pregnancy rates were 57.56%, 51.76% and 35.95% versus 37.79%, and the early abortion was 23.08%, 15.42% and 22.35% versus 34.55% respectively for embryos cryopreserved on D5, D6, D7 and D3. There were significant differences between D5 and D3 rates of ectopic pregnancy and early abortion. The sex ratio, the birth weight and birth defect were not statistically different among four groups. Conclusion: Blastocyst transfer achieved a higher implantation rate than vitrified cleavage stage embryo and decreased ectopic pregnancy rate. With increased incubation days before expansion blastocyst formed, the implantation rate is reduced and the early abortion rate increases. [ABSTRACT FROM AUTHOR]