Advantage of day three over day two embryo transfer

Objectives: This study was done to compare embryo quality and pregnancy rate between day two and day three embryo transfer, the effect of extended culture on embryo development potential also analysed. Methods: In a 18 month period extending from January 2014 to june 2015 all couples undergoing infertility treatment in the form of intracytoplasmic sperm injection whatever the cause and in whom fresh embryo transfer were done (258 cycle) were included in this prospective study. The patients classified into two groups according to the day of embryo transfer. The policy of transfer was uniform in both groups and the transfer was done according to patient criteria or the number of embryos available. Results: the main outcome measures were embryo quality, embryo development potential and pregnancy rate.  Our data suggest no significant statistical difference in pregnancy rate between day two and day three embryo transfer ( 42.9 versus 42.0% respectively P>0.05). The percentage of good quality embryos was slightly insignificantly higher in day two group than day three (86.03 vs. 84.7%, P>0.05). the percentage of slow growing embryos was significantly higher in those cultured for three days than those remain for just two days in vitro (15.9 vs. 23.3 , P<0.05) . Conclusion: a similar pregnancy rate was obtained by doing embryo transfer on day two and day three after intracytoplasmic sperm injection in spite of slight regression in embryo quality and higher rate of developmental delay in cases of extended culture. So no advantage for day three over day two embryo transfer.