제   목 Evaluation of early and late sibling embryo development in a single versus sequential medium
등록일 2015/12/18 조회수 435 첨부파일
2015 PSRM 10th Biennial Meeting
2015 KSRM 69th Annual Meeting

J.H. Jeong, T.H. Kim, Y.Y. Lee, B.Y. Kim, H.H. Kang, H.M. Jang, S.Y. Moon, M.J. Lee, Y.S Kim, S.W. Lyu, J.Y. Kim, W.S. Lee, T.K. Yoon, D.R. Lee


Introduction
The success of in vitro fertilization techniques is defined by multiple factors including embryo culture conditions, related to the composition of the culture medium. Currently, there is a discussion about the ideal composition of culture medium with two opposing views "back to nature" and "embryo free choice". According to the "back to nature/need for sequential medium" principle, embryo culture medium mimic in vivo conditions and the "embryo free choice/singe culture medium" paradigm, the embryo is cultured in a single medium which is constant and contains all the components needed during its development.
Currently, blastocyst culture and transfer is an important technique developed for in vitro fertilization (IVF) that high implantation rates while minimizing the risk of multiple pregnancy. In some case, embryos for blastocyst transfer are usually chosen based on morphology of early cleavage embryo. To select embryo for transfer based on an assessment of cell number and morphological appearance on day 2 or day 3 of development. The ability to identify on day 2 which embryos will develop into blastocysts offers the potential to increase the high implantation and pregnancy rates associated with blastocyst transfer.

Objective
This study aimed to compare early and late embryo development using sibling embryo culture through day 5 in single medium and sequential medium. Additionally, this study was to investigate the embryo development from day2 to day5 on each culture medium of fresh IVF cycle and to predict the blastocyst rate according to the composition of the culture medium

Material&method
The study was performed from July 2014 to April 2015. 140 patients in IVF treatment with more than ten follicles at hCG injection time were counted for the study. Their oocytes were split and randomly allocated between single medium and sequential medium.

Result
Embryo score of day 3 embryo cultured in single medium and sequential medium was 18.3 4.24 and 18.1 3.63, and total blastocyst rate of day 5 was 36.8% (290/789) and 34.4% (298/866). There were no statistical differences in both groups. However, on day 2, the percentage of good quality embryo (GQE) cultured in single medium was significantly higher than in sequential medium (46.0% (363/789) vs 40.4% (350/866)) (figure 2).
The mean value of fertilized oocyte was 11.85.0. On day 2, each average number of blastocyst in one GQE was 2.7, in two GQE was 3.0 and more than three GQE was 4.6 in all embryos (figure 3). Moreover, on day 5, in cases when more than one blastocyst was formed, each ratio of patient in one GQE was 60.0%, in two GQE was 64.3%, and more than three GQE was 84.2% in all patients (figure 4).

Conclusion
The results show that the percentage of GQE was higher when the embryos were cultured in the single medium compared to the sequential medium on day 2, and number of blastocyst generated has been shown to correlate with numbers of GQE. In addition, we suggested that the possibility of transfer of blastocyst may be increased if there are more than three GQE at day 2.
In conclusion, early cleavage embryo assessment is important in predicting blastocyst rate using a single medium or sequential medium. So, this result offers an indicator that may assist in optimal blastocyst transfer and reduce the cancelation risk of blastocyst transfer.
 This work was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family affairs, Republic of Korea (A120080)