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

This meta-analysis of couples with well defined unexplained infertility undergoing IVF favors the use of intracytoplasmic sperm injection to increase fertilization rates and decrease the risk of total fertilization failure.


Lauren N. C. Johnson, M.D., Isaac E. Sasson, M.D., Ph.D., Mary D. Sammel, Sc.D., Anuja Dokras, M.D., Ph.D.

Volume 100, Issue 3, Pages 704-711, September 2013



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.


Systematic review and meta-analysis.


IVF centers.


Couples with well-defined unexplained infertility undergoing IVF.


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.


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.


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.

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