Immunofluorescent Study of Human MII Oocytes Failed to Fertilize after IVF and ICSI

Objective To discuss the reason why human MⅡ oocytes failed to fertilize after IVF and ICSI. Methods The unfertilized human MⅡ oocytes were collected 24-48 h after IVF and ICSI and stained for immunoflurescence and PI counterstain. The types of fertilization failure were identified under the fluorescence microscopy. Results About 55.8% oocytes in IVF were found no sperm in them,which were more than that in ICSI (9.7%) (P<0.01). About 14.9% oocytes in IVF and 58.1% in ICSI displayed oocyte activation failure. The difference was significant (P<0.01). Defects in pronuclear formation and/or migration was found in a similar proportion of oocytes both after IVF (25.3%) and ICSI (32.3%)(P>0.05). There were 3.9% oocytes with other abnormalities were observed in IVF but none in ICSI. Conclusion The main reason of fertilization failure after IVF was no sperm penetration. However fertilization failure after ICSI was mainly associated with incomplete oocyte activation.