Does intracytoplasmic sperm injection improve the fertilization rate and decrease the total fertilization failure rate in couples with well-defined unexplained infertility? A systematic review and meta-analysis

Objective: To determine if intracytoplasmic sperm injection (ICSI), compared with conventional insemination, improves fertilization rates and prevents total failed fertilization (TFF) in couples with unexplained infertility. Design: Systematic review and meta-analysis. Setting: IVF centers. Patient(s): Couples with well-defined unexplained infertility undergoing IVF. Intervention(s): A systematic review was performed by searching Medline and Embase for 1992-2012. Studies in which sibling oocytes were randomly split between conventional insemination and ICSI were included. A random effects model was utilized for the meta-analysis. Meta-analysis of Observational Studies in Epidemiology guidelines were applied. Main Outcome Measure(s): Fertilization rate and TFF rate by insemination method. Result(s): Eleven studies with a total of 901 couples (female age range 30-35 years) with 11,767 sibling oocytes were included in the meta-analysis. The pooled relative risk (RR) of a mature oocyte fertilizing was higher with ICSI than with conventional insemination (RR 1.49, 95% confidence interval [CI] 1.35-1.65.) The pooled RR of fertilization per allocated oocyte (before randomization) was higher with ICSI than with conventional insemination (RR 1.27, 95% CI 1.02-1.58; n = 5 studies.) The pooled RR of TFF was significantly higher with conventional insemination than with ICSI (RR 8.22, 95% CI 4.44-15.23). The number of subjects needed to treat with ICSI to prevent one case of TFF was five. Conclusion(s): This meta-analysis favors the use of ICSI to increase fertilization rates and decrease the risk of TFF in couples with well-defined unexplained infertility. Further studies are needed to determine the impact on clinical pregnancy and live birth rate. ((C) 2013 by American Society for Reproductive Medicine.)