Association of TNF-α genetic polymorphisms with recurrent pregnancy loss risk: a systematic review and meta-analysis

Background: Several studies on the association of tumor necrosis factor alpha (TNF-alpha) polymorphisms with recurrent pregnancy loss (RPL) risk have reported conflicting results. The present meta-analysis was conducted to provide a more precise estimation of these relationships and to investigate the real association between TNF-alpha polymorphisms and RPL. Methods: An extensive eligible literature search for relevant studies was conducted on PubMed, Embase, and The Cochrane Library from their inceptions to May 12, 2015. Specific inclusion criteria were used to evaluate articles. The odds ratio (OR) with 95% confidence intervals (CIs) were used to assess the strength of associations. Statistical analyses were performed by the STATA12.0 software. Results: 10 case-control studies including 1430 RPL patients and 1727 healthy controls were identified. Metaanalysis indicated that TNF-alpha-308G/A (rs1800629) polymorphism in the TNF-alpha gene correlated with elevated RPL risk whereas no significant association was observed between TNF-alpha-238G/A (rs361625) and RPL. Conclusions: The current meta-analysis demonstrates that TNF-alpha-308G/A polymorphism in the TNF-alpha gene is associated with susceptibility to RPL.