Pregnancy rate and live birth rate are higher after blastocyst transfer than after day 2 and day 3 embryo transfer following Intracytoplasmic sperm injection (ICSI)

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 livebirth 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.