Effect of Sequential Embryo Transfer in vitro Fertilization

체외수정시술시 Sequential ET의 효용성에 관한 연구

Objective: The objective of this study is to influence of sequential embryo transfers in an invitro fertilization was examined. Method: After in vitro fertilization, a maximum of 6 fertilized oocytes was enrolled in this study. At day 3 after an oocytes retrieval, embryos with good quality were transferred (mean 4.9), remaining embryos (mean 2.0/cycle) were cryopreserved at blastocyst stage (Group 1). At day 5 after oocytes collection, second a embryo transfer (mean 1.2/cycle) was performed, if one of these embryos had reached the blastocyst stage (Group 2) using P1 supplemented with 10 SSS and 30% Follicular fluid. No statistical difference in the pregnancy rate could be seen between the group without a second embryo transfer (n=21; 28.6%) and the group with a second transfer (n=52; 28.8%). Results: The incidence of multiple pregnancy rate per embryo transfer was not statistically different between both group and no high-rank multiple pregnancy (greater than triplete) were observed (0.9%, 15.4%, respectively, p=0.74, ${\chi}^2$). Out of 114 cycles (506 embryos) cultured embryos in group 2, 52 cycles (159 embryos, 29.8%) reached the blastocyst stage. Conclusion: The second transfer did not have a significant effect on the pregnancy rate. The most important factor for the pregnancy seems to be the quality of the embryos transferred on day 3 following oocyte retrieval. We recommend embryo transfer is performed only one, day $2{\sim}3$ or D5.