A Study Comparing In Vitro Fertilization Results After Day 2 and Day 3 Embryo Transfer

Lee, You Kyoung; Lee, Jin; Kim, Mi Young; Lee, Yu Il

Abstract

OBJECTIVE
To compare the clinical outcomes of day 2 embryo tranfer with those of day 3 embryo transfer after In Vitro Fertilization (IVF).
METHODS
Medical records of 192 patients (217 cases) undergoing IVF-ET at Chonnam National University Hospital from February 1995 to July 2001 were reviewed. The number of cases of the day 2 transfer (D-2) group and the day 3 transfer (D-3) group was 152 and 65, respectively. Clinical characteristics, mean number of fertilized oocytes, frequency of embyo qualities, mean number of embyo transferred, cumulative embryo score (CES) per transfer, pregnancy rate per cycle, clinical pregnancy rate per cycle and implantation rate per transferred embyo were compared between the two groups.
RESULTS
In embyo quality, grade I in D-2 group (69.5%) was much more than in D-3 group (52.3%) in number, and grade III and IV in D-3 group (9.7% and 6.2%) was much more than in D-2 group (1.0% and 0.2%). CES was significantly higher in D-3 group than in D-2 group (62.4+/-40.0 versus 49.1+/-34.2). However, there were no statistically significant differences between the two groups in number of fertilized oocytes, number of embryo transferred, pregnancy rate, implantation rate and pregnancy outcome. There were also no significant differences between the two groups in implantation and pregnancy rates according to age, under 35 vs over 35 and the presence or absence of previous IVF-ET failure.
CONCLUSION
There were no difference in the pregnancy rate and implantation rate between the two groups. The CES which indicates the quality of embryo was higer in D-3 group than in D-2 group. Since this study did not show the direct effect of better quality of D-3 embryo on implantation rate and pregnancy rate, further investigation should be needed. In addition, further studies about improving culture media for embryonic development and selecting better quality embryos for delayed embryo transfer should be continued.