Clinical Analysis Of Various Stages Of Blastocyst In Frozen-thawed Cycle

Objective: To explore the relationship between blastocyst in different stages and clinical outcome in frozen-thawed cycle.Methods: This retrospective study included 674 frozen-thawed blastocysts transfer cycles in Reproductive Medicine center of Nanning Second People’s Hospital from January 2018 to December 2018.The cycles were divided into two groups according to the blastocyst formation:Day5 group(D5,n=321)and the Day6 group(D6,n=353).According to the number of blastocysts transferred,two groups were divided into single blastocyst transferred on Day5(SBT-D5,n=151),single blastocyst transferred on Day6(SBT-D6,n=188),double blastocysts transferred on Day5(DBT-D5,n=170),double blastocysts transferred on Day6(DBT-D6,n=165).Then according to the blastocyst grade,the groups were subdivivided into single high-quality blastocyst group of Day5(D5-H,n=84),single poor-quality blastocyst group of Day5(D5-L,n=67),single high-quality blastocyst group of Day6(D6-H,n=57),single poor-quality blastocyst group of day6(D6-L,n=131),double high-quality blastocysts group of Day5(D5-2H,n=75),high and poor quality blastocysts group of Day5(D5-1H,n=41),double poor-quality blastocysts group of Day5(D5-2L,n=54),double high-quality blastocysts group of Day6(D6-2H,n=24),high and poor quality blastocysts group of Day6(D6-1H,n=42),double poor-quality blastocysts group of Day6(D6-2L,n=99).To compare the pregnancy outcomes between the different groups,such as HCG positive rate,implantation rate,clinical pregnancy rate,early miscarriage rate,late miscarriage rate,ectopic pregnancy rate,live birth rate and multiple pregnancy rate.Results: 1.There were no significant differences in the age of egg retrieval,recovery age,duration of infertility,endometrial thickness,average number of blastocyst transferred,Preparation method for endometrium,type of infertility,source of embryos,and number of blastocyst transferred between D5 group and D6 group(P>0.05).2.HCG positive rate,the implantation rate,clinical pregnancy rate and live birth rate at D5 group were statistically significantly higher than those at D6 group(75.70% vs 68.84%,61.10% vs 50.97%,72.90% vs 62.32%,63.24% vs 49.58%,P<0.05).The early miscarriage rate at D5 group was statistically significantly lower than that at D6 group(8.55% vs 17.72%,P<0.05).3.There were no significant differences between D5 single blastocyst group and D6 single blastocyst group in the implantation rate,clinical pregnancy rate and live birth rate(56.29% vs 54.79%,56.29% vs 54.79%,49.01% vs 41.49%,P>0.05).Compared with D6 single blastocyst group,there was lower early miscarriage rate at D5 single blastocyst group(8.24% vs 22.33%,P<0.05).4.The implantation rate,clinical pregnancy rate and live birth rate at D5 double blastocysts groups were statistically significantly higher than those at D6 double blastocysts groups(63.24% vs 48.79%,87.65% vs 70.91%,75.88% vs 58.79%,P<0.05).5.Comparing the clinical outcomes of single blastocyst with different qualities,HCG positive rate,implantation rate,clinical pregnancy rate and live birth rate in the D5-H group were the highest,and the early abortion rate was the lowest.Poor-quality D6 single blastocyst group had the highest early miscarriage rate in the four groups.There was significant difference between high-quality Day5 single blastocyst group and poor-quality D6 single blastocyst group in the early miscarriage rate(25.35% vs 6.25%,P<0.05).No significant difference were found at other groups.6.In the different quality double blastocysts groups,HCG positive rate,implantation rate,clinical pregnancy rate,and live birth rate in the D5-2H were the highest.The implantation rate and clinical pregnancy rate at different quality D5 groups(D5-2H,D5-1H,D5-2L)were higher than those at corresponding D6 groups(D6-2H,D6-1H,D6-2L).7.The multiple p1 regnancy rate at the D5/D6 double blastocysts group was higher than that at the D5/D6 single blastocyst group.Conclusion: 1.The clinical outcome of D5 was better than D6 in frozenthawed blastocyst transfer cycle.2.In frozen-thawed cycle,transfer of single blastocyst could reduce multiple pregnancy rate.