Objective To evaluate the effectiveness and safety of aromatase inhibitors in ovulation induction for women with unexplained infertility. Methods The databases such as CNKI (1994 to June 2011), WanFang Data (1982 to June 2011), PubMed (1966 to June 2011) and The Cochrane Library (Issue 6, 2011) were searched to collect randomized controlled trials (RCTs) and quasi-randomized controlled trials (quasi-RCTs) for the comparison between aromatase inhibitors (AIs) and clomiphene citrate (CC). The quality of the retrieved trials was critically appraised and meta-analyses were conducted using RevMan 5.0.1 software. Results Nine studies were included; all of them were published in English. The results of meta-analyses showed there were no significant differences between AIs and CC in the pregnancy rate (RR=1.02, 95%CI 0.71 to 1.47), miscarriage rate (RR=1.00 95%CI 0.61 to 1.63), multiple pregnancy rate (RD= –0.02, 95%CI –0.07 to 0.03), and incidence rate of adverse events (RD=0.00, 95%CI –0.01 to 0.01); there were still no significant differences between the AIs+gonadotropin (Gn) group and the CC+Gn group in the pregnancy rate (RR=0.98, 95%CI 0.68 to 1.42), miscarriage rate (RR=1.23, 95%CI 0.70 to 2.15), multiple pregnancy rate (RD=0.00, 95%CI –0.10 to 0.10), and incidence rate of adverse events (RD=0.00, 95%CI –0.10 to 0.01). Conclusion Whether aromatase inhibitors can replace clomiphene citrate in ovulation induction for women with unexplained infertility is still an issue that has to be identified by performing well-designed large scale RCTs with longer follow-up duration.
