Association of tumor necrosis factor-α gene promoter polymorphisms (-308G/A, -238G/A) with recurrent spontaneous abortion: a meta-analysis

Abstract

Tumor necrosis factor-α (TNF-α) gene promoter polymorphisms (-308G/A, -238G/A) have been associated with increased recurrent spontaneous abortion (RSA) risk, but the results of published articles are controversial. Hence, a meta-analysis was performed to assess the effect of TNF-α -308G/A, -238G/A polymorphisms on RSA risk. Heterogeneity testing and sensitivity analysis were performed using RevMan 5.0 software. Publication bias was assessed by the funnel plot method and modified Egger's linear regression test. In 12 studies for the TNF-α -308G/A polymorphism, the summary odds ratio (OR) with the corresponding 95% confidence interval (95% CI) was 1.04 (95% CI: 0.86, 1.26) under a fixed-effect model in the overall population. In 5 studies for the TNF-α -238G/A polymorphism, the summary OR with the corresponding 95% CI was 1.11 (95% CI: 0.60, 2.03) under a random-effect model in the overall population. We could not identify the sources of heterogeneity for TNF-α -238G/A. In addition, no evidence of publication bias was detected. The results of this meta-analysis indicate that TNF-α -308G/A, -238G/A polymorphisms are not significantly associated with the risk of RSA in the overall population. However, more convincing evidence is required to draw a solid conclusion on the relation between the TNF-α -238G/A polymorphism and the risk of RSA.