Hi - I found this

Day 0 Egg retrieval
Sperm collection and preparation
Insemination
Day 1 Check eggs for fertilization (the presence of two pronuclei or PN's)
Day 2 Embryos at the 4-cell or more stage of development
Day 3 Embryos at the 8-cell or more stage of development
Day 4 Embryos at the compacted morula (16-32 cell) stage
Day 5 Embryos at the blastocyst stage of development


Hope this helps

xxx Sue xxx