The impact of two different thaw protocols on outcomes of vitrified cleavage-stage embryos transfer.

The objective of this study was to evaluate the gestational results obtained with vitrified-thawed human cleavage-stage embryo by two different thaw protocols. Embryo development was observed to cleavage-stage and embryos were cryopreserved by vitrification on day 3 after oocyte retrieval. 51 cycles were thawed using vitrification warming kit with decreasing concentrations of sucrose in 3 dilutions ( 1.0, 0.5 and 0 mol per L respectively) as group 1, 56 cycles were thawed with decreasing concentrations of sucrose in 5 dilutions ( 0.8, 0.6, 0.33, 0.2 and 0 mol per L respectively) as group 2. Embryo survival (> 50 percent intact blastomeres), complete embryo survival (100 percent intact blastomeres), pregnancy and implantation rates were compared, and development rates the day after thawing were also compared. Multivariate analysis showed a significant difference in embryo immediate morphological survival rate, complete survival and clinical pregnancies rate between the two groups respectively (87.0 vs. 98.6 percent, p=0.000; 71.0 vs 82.0 percent embryo subsequent development rates, mean number of transferred embryos was similar between the two groups. (61.4 vs. 61.3 percent, p=0.502; 2.2 +/ 0.5 vs. 2.4 +/- 0.6, p=0.113). In addition, no differences in implantation rate were observed between two groups (17.7 vs. 25.6 percent, P=0.138). No difference in the multiple pregnancy rates was found among the two groups also.

Effect of the size of zona pellucida thinning by laser assisted hatching on clinical outcome of human frozen-thawed embryo transfers.

Of 122 consecutive procedures, 31 were not assisted hatching (AH), which served as the control group, 34 were AH with 40 microm thinning of the zona, and 57 were AH with 80 microns of the zona thinning. The pregnancy and implantation rates were significantly higher in 80 microns thinning group compared to control group (40.3 vs. 16.1 percent, P=0.03; 21.5 vs. 7.5 percent, P=0.007, respectively). In addition, the implantation rate was signigicantly higher in 80 microns group than in 40 microns group (21.5 percent vs.9.4 percent, P=0.024). The results indicated that the size of the zona pellucida thinning by laser may influence the pregnancy and implantation rates following frozen-thawed cleaved embryo transfer.

Successful pregnancy following the transfer of vitrified blastocyst which developed from poor quality embryos on day 3.

BACKGROUND: The selection of pre-embryos for transferred is based on morphological appearance. But some poor quality cleaved embryos also can be cultured to the blastocyst stage and implanted. OBJECTIVE: To assess the clinical pregnancy outcomes of blastocyst transfer which developed from poor quality embryos. MATERIALS AND METHODS: A total of 109 cleaved embryos with poor quality were cultured to day 5/day 6 and 27 (24.8%) blastocysts were collected from the 15 cycles/patients undergoing conventional IVF. All the blastocysts were cooling with fast-freezing. Then the blastocysts were warmed for transfer. RESULTS: All of 25 vitrified blastocysts (92.6%) survived after warming and were transferred to 15 patients. Five of the women became pregnant. CONCLUSION: Our results suggest that vitrified human day 5/day 6 blastocyst transfer which develop from poor quality embryo at day 3 can contribute to increasing cumulative pregnancy rates in assisted reproduction.