Prediction of embryonic development and clinical outcome following ICSI according to the stages of nuclear maturation division

fertilization rate was 80.0%, 57.1%, 76.2%, 50.0% respectively (overall mean 1⁄4 67.3%). In the control group the normal fertilization rate was 79.1%. The normal fertilization rate was significantly lower in oocytes which were cultured from MI to MII stage than in the control group (67.3% VS 79.1%; P < 0.05). The overall rate of blastocyst development in the MI to MII cultured group was 38.5% (5/13), and good quality blastocysts 30.8% (4/13). In the control group the rates were 32.1%(433/1349) and 26.0%(351/1349)respectively. There was no significant difference between these two groups. CONCLUSION: This work suggests that in cases where only a few oocytes or only MI oocytes are retrieved, additional culture and observation of PB release to time ICSI may be useful in improving embryo development potential. Future work should include further consideration of the optimum timing of PB release for ensuring the best embryo development potential.