​16-cell Versus Blastocyst for Embryo Transfer. Witch Is Better? S.C. Lee, D.M. Min, R.S. Ryu, Y.C. Park, C.K. Park, J.H. Kim​

It will be presented at the 55th Annual Meeting of the American Society of 

Reproductive Medicine in Toronto, Canada, September 25th to 29th, 1999

16-cell Versus Blastocyst for Embryo Transfer. Witch Is Better?

1S.C. Lee, 1D.M. Min, 1R.S. Ryu, 1Y.C. Park, 2C.K. Park, 1J.H. Kim

1Institute of Human Infertility and Genetics, Saewha Women's Clinic, 

Pusan, Korea

2Department of Animal Science College of Animal Agriculture

Kangwon University, Chunchon, Korea

Objectives: Many reports exist about embryo transfer of early cleavage 

stage through to the blastocyst stage in in vitro culture in other to 

increase pregnancy rate. However, no clear information is available 

regarding the effects of stage in in vitro culture on pregnancy rate. 

Therefore, the purpose of this study was to evaluate whether embryo stage 

in in vitro culture affects pregnancy rate.

Design: Retrospective case study utilizing records of pregnancy rate. 

Analysis of 16-cell (day 4; 75∼80 hours post-insemination) versus 

blastocyst (day 5; 120∼125 hours post-insemination) embryo transferred.

Materials and Methods: The subjects consisted of 161 embryo transfer (ET) 

cycles under the age of forty from January 1996 to December 1997 who 

underwent ET in Saewha Women's Clinic IVF Center. Medium for in vitro 

culture was modified Tyrode's solution (mTLP) without glucose, phosphate 

and phenol red. This medium was essentially the same as that used by Kim 

et al., (1993). There were no other differences between the culture 

condition for these two years. Pregnancy were defined as clinical 

pregnancy when fetal heat beating were confirmed and ongoing pregnancy 

when pregnancy persist more than 16 weeks. kata analyzed by chi-square 

method.

Results: 첨부파일

Conclusions: Much higher pregnancy rat after IVF-ET observed in 16-cell 

stage than blastocyst stage reveals that implantation of embryos 

transferred from in vitro culture take place much easily in 16-cell stage. 

It is known that embryo before blastocyst stage is found in oviduct and 

blastocyst stage is found only in uterus. Owing to above results embryo 

before blastocyst stage, 16-cell stage, is strongly recommend to 

transferred in uterus in other to increase pregnancy rate.

Reference: Kim JH, Niwa K, Lim JM, Okuda K. (1993) Effects of phosphate, 

energy substrates, and amino acids on development of in vitro-matured, in 

vitro-fetilized bovine oocytes in a chemically defined, protein-free 

culture medium. Biol. Reprod. 48:1320-1325.