Purpose: To examine the blastocyst formation rates of day-2 fertilized oocy
tes.
Methods: A retrospective study of the outcomes/blastocyst formation of day-
2 fertilized oocytes was undertaken.
Results: Fertilization rates of day-1 and -2 oocytes by intra-cytoplasmic s
perm injection were similar: The development frequencies to four cells were
similar However the blastulation rates were significantly lower from the d
ay-2 fertilized eggs. The fertilization rates from day-2 conventional in vi
tro fertilization reinsemination were lower than the fertilization rates of
day-1 oocytes. The blastulation rates from day-2 fertilized eggs were also
lower than the rates from day-1 fertilized eggs in the in vitro fertilizat
ion group.
Conclusions: Fertilization is nor a goad indicator to predict the viability
of fertilized oocytes. Day-2 fertilized oocytes had significantly lower bl
astocyst formation races than the rates from day-1 fertilized oocytes.