Abstract
ABSTRACT

Objective
To compare the differences in outcome when embryo transfer was performed on day 2, day 3 and day 5 following ICSI.
Subjects and Methods
A total of 644 subjects undergoing ICSI at Islamabad Clinic Serving Infertile Couples, with embryo transfers on day 2, day 3 and day 5 were included. It was carried out between February 2000 and February 2005. Main outcomes measured were fertilization, pregnancy and live birth rates.
Results
The percentage of Metaphase II oocytes retrieved and the fertilization rate were significantly (P<0.001) higher in blastocyst transfer subjects. Day 5 transfer subjects were observed with significantly (P<0.01) higher number of grade I embryos as compared to day 2 and day 3 embryo transfers. The mean number of embryos transferred was not significantly different in cleavage stage (day 2 and day 3) and blastocyst stage (day 5) embryo transfers. The cumulative pregnancy rate per embryo transfer and live birth rate were higher in blastocyst stage subjects (51.3% and 39.6%), as compared to day 2 (42.5% and 19.9%) and day 3 (37.6% and 33.4%) embryo transfers.
Conclusion
Our data suggests that blastocyst transfer has a higher pregnancy rate with a higher live birth rate. (Rawal Med J 2010;35: ).
Key words
ICSI, ART, blastocyst transfer, cleavage stage, pregnancy outcome, live birth rate.
INTRODUCTION
The delivery of a single, healthy child is the desired outcome of human assisted reproductive techniques.1 The only guaranteed way to reach this goal is to restrict oneself to single embryo transfer.2 The primary aim of elective single embryo transfer (eSET) is to reduce the multiple pregnancies while maintaining an acceptable overall pregnancy rate.3 The question is, therefore, at what stage to transfer the human embryo is back to the uterus?1 In human IVF, the embryo is routinely transferred to the uterus on day 2 or 3 of development, which is between 4 and 8 cells. The timing of the arrival of the embryo in the uterus, however, is premature compared with the situation in vivo, where the embryo enters the uterus at the morula stage 4-5 days after ovulation.4,5 The endometrium, on day 5 post-conception, seems to be optimal for embryos to implant and mirrors the implantation time in natural conceptions, as it has been demonstrated that uterine contractility decreases at the time of blastocyst transfer when compared to early stage transfers on day two.6
Currently, the elective embryo transfer at the blastocyst stage (day 5) is the most important method available for attaining high implantation and pregnancy without the risk of multiple pregnancies.7-9 Laverage et al observed no difference in implantation and pregnancy rates between transfers on day 2 versus day 3 (23.8 versus 23.8% and 47.9 versus 46.8% respectively).5 Coskun et al reported overall same pregnancy rate (39%) in day 3 and day 5 transfers and almost same implantation rates (21 and 24% for day 3 and day 5).10 A randomized study in an

Key words: ICSI, ART, blastocyst transfer, cleavage stage, pregnancy outcome, live birth rate.