Analysis Of Pregnancy Outcomes Between Cleavage Stage Embryo Transfer And Blastocyst Transfer In Fresh And Frozen-thawed Cycles

Objective:To analyze the clinical data and to compare the pregnancy outcomes between cleavage stage embryo and blastocyst in fresh and frozen-thawed cycles,and than to explore the related factors affecting the clinical pregnancy rate of cleavage stage embryo in frozen-thawed cycles,for the purpuse of providing guidance for clinical practice.Methods:This study retrospectively analyzed the clinical data of infertile patients undergoing cleavage stage embryo transfer and blastocyst transfer in fresh and frozen-thawed cycles in the the Reproductive Medicine center of the First Affiliated Hospital of Guangxi Medical University from May 1,2015 to May 31,2018.According to the inclusion criteria and exclusion criteria,it included 2907 cycles,according to the different transplanting time is divided into two groups:the fresh cycle group(group A,n=1584)and the frozen-thawed cycle group(group B,n=1323),according to the different types of embryo,the fresh cycle group(group A,n=1584)is divided into the cleavage stage embryo group(group D3 A,n=1445)and blastocyst group(group D5/D6 A,n=139),the frozen-thawed cycle group(group B,n=1323)is divided into the cleavage stageembryo group(group D3 B,n=960)and blastocyst group(group D5/D6 B,n=363),and than blastocyst group(group D5/D6 B,n=363)is divided into day 5 blastocyst group(group D5 B,n=190)and day 6 blastocyst group(group D6 B,n=173).To compare the pregnancy outcomes between the different groups,such as the implantation rate,clinical pregnancy rate,ectopic pregnancy rate,abortion rate,live birth rate,preterm birth rate and multiple pregnancy rate and so on.To analysis the related factors affecting the clinical pregnancy rate of cleavage stage embryo in frozen-thawed cycles(D3B group).Results:1.The embryo implantation rate of group D3 A was significantly lower than group D5/D6A(33.39% vs 46.75%,P < 0.001).There were no statistically significant differences in clinical pregnancy rate,abortion rate,biochemical pregnancy rate,ectopic pregnancy rate,live birth rate,preterm birth rate and multiple pregnancy rate between the group D3 A and the group D5/D6A(P > 0.05).2.The embryo implantation rate of group D3 B was significantly lower than the group D5/D6B(31.02% vs 43.20%,P<0.001).The clinical pregnancy rate,live birth rate in the D3 B group were all lower than those in the group D5/D6 B,with significant differences(P<0.05).There were no statistically significant differences in abortion rate,biochemical pregnancy rate,ectopic pregnancy rate,preterm birth rate and multiple pregnancy rate between group D3 B and group D5/D6B(P>0.05).3.There were no statistically significant differences in embryo implantation rate,clinical pregnancy rate,abortion rate,biochemical pregnancy rate,ectopic pregnancy rate,live birth rate,preterm birth rate and multiple pregnancy rate between group D5/D6 A and group D5/D6B(P>0.05).4.The embryo implantation rate,clinical pregnancy rate and live birth rate of group D5 B was higher than group D6 B with statistically significant differences(P < 0.05).There were no statistically significantdifferences in abortion rate,biochemical pregnancy rate,ectopic pregnancy rate,preterm birth rate and multiple pregnancy rate between the group D5 B and the group D6B(P>0.05).5.The number of embryos transferred and the number of high qualified embryos transferred were the main factors affecting the clinical pregnancy rate of group D3 B.Conclusion:1.Compared with the cleavage stage embryo in fresh cycle,blastocyst transfer has higher implantation rate and can be obtained similar clinical pregnancy rate and live rate by transplanting relatively fewer embryos.2.Compared with the cleavage stage embryo in frozen-thawed cycle,blastocyst transfer has higher implantation rate and can be obtained higher clinical pregnancy rate and live rate by transplanting relatively fewer embryos.3.There was no difference in pregnancy outcomes between the fresh cycle and frozen-thawed cycle for blastocyst transplantation.4.The implantation rate,clinical pregnancy rate and live birth rate of D5 blastocysts were higher than those in D6 blastocysts in frozen-thawed cycle.5.The number of embryos transferred and the number of high qualified embryos transferred were the main factors affecting the clinical pregnancy rate of cleavage stage embryo in frozen-thawed cycles.When the same number of embryos is transferred(one-two number),the clinical pregnancy rate is enhanced with the higher number of high qualified embryos.