Pregnancy Outcome Of Sequential Embryo Transfer In Frozen Embryo Transfer Cycle

Objective To explore the influence of sequential embryo transfer on pregnancy outcome and the indication of sequential embryo transfer by comparing and analyzing the general situation and pregnancy outcome of sequential embryo transfer and conventional embryo transfer in the frozen embryo cycle.Methods Retrospective analysis of 970 patients with frozen embryo cycle,all patients were treated with hormone replacement cycle method to prepare the endometrium.According to the method of embryo transfer,the patients were divided into two groups: sequential embryo transfer group(n=130)and conventional embryo transfer group(n=840).The baseline characteristics,clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate of the two groups were compared and analyzed.Then the patients of the two groups were further conducted stratification analysis according to the number of embryos transferred: 92 patients underwent sequential transfer of two embryos,778 patients underwent conventional transfer of two embryos,38 patients underwent sequential transfer of three embryos,62 patients underwent conventional transfer of three embryos.According to the different stages of blastocyst transferred,they were divided into 4 groups: 73 patients underwent sequential transfer of D5 blastocyst,107 patients underwent conventional transfer of D5 blastocyst,57 patients underwent sequential transfer of D6 blastocyst,82 patients underwent conventional transfer of D6 blastocyst.According to the number of previous failure cycles,the patients were divided into 6 groups: 56 patients underwent sequential transfer for the first embryo transfer,312 patients underwent conventional transfer for the first embryo transfer,43 patients underwent sequential transfer who had one embryo transfer failure,294 patients underwent conventional transfer who had one embryo transfer failure,31 patients underwent sequential transfer who had more than one embryo transfer failure and 234 patients underwent conventional transfer who had more than one embryo transfer failure.Then the study further stratified analysis according to different stages of blastocyst transferred based on previous failure cycles.The baseline characteristics,clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate were compared among the groups.SPSS 26.0 software was used for statistics.P < 0.05 was statistically significant.Results 1.The clinical pregnancy rate and implantation rate of the sequential embryo transfer group were statistically higher than those of the conventional embryo transfer group(P < 0.01);there were no significant differences in multiple pregnancy rate and miscarriage rate(P > 0.05).2.Stratified comparison according to the number of embryos transferred:(1)In the patients with two embryos transferred,the clinical pregnancy rate and implantation rate of the sequential embryo transfer group were statistically higher than those of the conventional embryo transfer group(P < 0.05);there were no significant differences in multiple pregnancy rate and miscarriage rate(P > 0.05).(2)In the patients with three embryos transferred,the clinical pregnancy rate and implantation rate of the sequential embryo transfer group were statistically higher than those of the conventional embryo transfer group(P <0.05);there were no significant differences in multiple pregnancy rate and miscarriage rate(P > 0.05).(3)There were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential two embryo transfer group and the sequential three embryo transfer group(P > 0.05).3.Stratified comparison according to the different stages of blastocyst transferred:(1)In patients with D5 blastocyst transferred,there were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential embryo transfer group and the conventional embryo transfer group(P > 0.05).(2)In patients with D6 blastocyst transferred,the clinical pregnancy rate of the sequential embryo transfer group was statistically higher than that of the conventional embryo transfer group(P < 0.05);there were no significant differences in implantation rate,multiple pregnancy rate and miscarriage rate(P > 0.05).(3)There were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential D5 blastocyst transfer group and the sequential D6 blastocyst transfer group(P > 0.05).4.Stratified comparison according to the number of previous failure cycles:(1)In the patients with the first embryo transferred,there were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential embryo transfer group and the conventional embryo transfer group(P > 0.05).Then stratified comparison according to the D5/D6 blastocyst transferred,there were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential embryo transfer group and the conventional embryo transfer group(P > 0.05).(2)In the patients with 1 previous failure,the clinical pregnancy rate and implantation rate of the sequential embryo transfer group were statistically higher than those of the conventional embryo transfer group(P < 0.05);there were no significant differences in multiple pregnancy rate and miscarriage rate(P > 0.05).Then stratified comparison according to the D5/D6 blastocyst transferred,there were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential embryo transfer group and the conventional embryo transfer group(P > 0.05).(3)In the patients with ≥2 previous failures,the implantation rate of the sequential embryo transfer group was statistically higher than that of the conventional embryo transfer group(P < 0.05);there were no significant differences in clinical pregnancy rate,multiple pregnancy rate and miscarriage rate(P > 0.05).Then stratified comparison according to the D5/D6 blastocyst transferred,there were no significant differences in the clinical pregnancy rate,implantation rate,multiple pregnancy rate and miscarriage rate between the sequential embryo transfer group and the conventional embryo transfer group(P > 0.05).Conclusion 1.Sequential embryo transfer in frozen embryo cycle can effectively improve the clinical pregnancy rate and implantation rate of patients.2.Sequential embryo transfer can improve the pregnancy outcome of patients with previous ART failure cycles.3.Sequential embryo transfer may improve the utilization rate of D6 blastocyst.