To examine the blastocyst formation rates of day-2 fertilized oocytes.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 intracytoplasmic sperm injection were similar. The development frequencies to four cells were similar. However, the blastulation rates were significantly lower from the day-2 fertilized eggs. The fertilization rates from day-2 conventional in vitro 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 fertilization group.Conclusions:
Fertilization is not a good indicator to predict the viability of fertilized oocytes. Day-2 fertilized oocytes had significantly lower blastocyst formation rates than the rates from day-1 fertilized oocytes.