Blastocyst Transfer in In Vitro Fertilization

Lee, W D; Kim, K H; Lee, S G; Lee, H K; Cho, H J; Kim, E Y; Yoon, H G; Park, S P; Yoon, S H; Lim, J H

Abstract

The objective of this study is to present our experiences about co-cultured blastocyst transfer in in vitro fertilization and embryo transfer (IVF-ET)and to assess the pregnancy and implantation rate. In preliminary study, from December 1994 to March 1995, in 274 IVF cycles, two or three 8 cell-embryos were transferred on day 3 after ovum pick-up (OPU) while the remaining embryos were further cultured for 48~ 72 hours using cumulus cell co-culture. On day 5 or day 6, one or two blastocysts were transferred again, so maximum number of embryos transferred was 4 (sequential ET). More over from April 1995 to June 1995, we performed 3 day ET or 5 day ET if more than 4 good embryos were available on day 2 (selective blastocyst transfer). In this case, maximum number of embrgos transferred was 5 in 3 day ET and 3 in 5 day ET, respectively. The pregnancy and implantation rate between 120 ETs performed on 3 day and 192 ETs on 5 days was analyzed. In sequential ET group, the percentage of blastocyst obtained was 48.3%. The clinical pregnancy rate and implantation rate was 44.5% (122/274)and 16.4% (170/1034), respectively. In selective blastocyst transfer group, on day 3 after OPU, 46 pregnancies per 120 ET (38.3%)and on day 5, 103 pregnancies per 192 ET (53.6%)were achieved (p < 0.01). There was no significant difference in the ongoing pregnancy rate between day 3 ET and day 5 ET: 33.3% (40/ 120)and 39.6% (76/192), respectively. The multiple pregnancy rate was 50% (20/40)and 57.9 % (44/76), respectively, but, triplet pregnancy rate was 27.5% (11/40)and 13.2% (10/76), respectively. The results suggest that blastocyst transfer allows good pregnancy rate and implantation rate. Further research is required about blastocyst grading and we may consider one or two blastocyst transfer, minimizing the incidence of multiple pregnancy.