Analysis of Embryo Implantation Capacity and Clinical Pregnancy Outcomes after Non-elective Single Embryo Transfer

Objective:To analyze the clinical pregnancy outcomes of non-elective single embryo transfer and dis-cuss the feasibility of elective single embryo transfer(SET).Methods:A retrospective analysis was carried out on in vitro fertilization-embryo transfer(IVF-ET) cycles of Center for Reproductive Medicine in Nanfang Hospital between January 1,2002 and August 31,2007.Only one embryo was available to transfer in 202 cycles,to analyze the relations of age,ovarian response,number of embryo blastomere,and clinical pregnancy rate.Results:The average clinical pregnancy rate was 19.8% in the 202 SET cycles.The pregnancy rates were 30.8%,19.4%,16.3%,and 9.5% in 30 yr,30～35 yr,36～40 yr,and 40 yr group,respectively,and there was no statistically significant difference(P=0.192).The pregnancy rates were 20.0% and 17.6% in normal response and low response with no statistically significant difference(P=0.673).The pregnancy rates were 7.7%,12.7%,15.6%,and 34.9% in the 2～3 cell embryo group,4～5 cell embryo group,6 cell embryo group,and 7～8 cell embryo group,respectively,and there was statistically significant difference among them(P=0.002).Conclusions:The clinical pregnancy rate closely related to the quality of embryo in the SET cycles,and the highest in the 7～8 cell embryo groups.For the ovarian normal response,elective SET can be applied to women under 35 years,and have satisfactory outcomes.