[Clinical analysis of intracytoplasmic sperm injection in patients with previous fertilization failure after conventional IVF].

OBJECTIVE: To analyze the clinical outcome of intracytoplasmic sperm injection (ICSI) in patients with previous fertilization failure after conventional IVF. METHODS: Data from 20 ICSI cases (22 ICSI cycles) with previous complete failure of fertilization or with fertilization rate < or = 20% between January 2002 and December 2004 were retrospectively analyzed. The control group consisted of 100 consecutive ICSI cycles for male factor infertility in the same period. RESULTS: The fertilization rate dramatically increased from 5.4% after conventional IVF to 76.9% after ICSI treatment (chi-squared = 264.66, P < 0.001). However, the fertilization rate in the subgroup with previous low fertilization was significantly lower than those in the control and in the subgroup without previous fertilization (67.9% vs 77.5%, 67.9% vs 84.2%). Compared with the control group, the subgroup without previous fertilization had a higher pregnancy rate and implantation rate, but only the difference in the implantation rate was statistically significant (40.5% vs 18.9%). CONCLUSION: ICSI can overcome previous fertilization failure with conventional in vitro fertilization and thus improve the clinical outcome.