Association of 14-bp insertion/deletion polymorphism of HLA-G gene with unexplained recurrent spontaneous abortion: a meta-analysis.

A meta-analysis was performed to assess the association of the human leukocyte antigen-G (HLA-G) 14 bp insertion (ins)/deletion (del) polymorphism with unexplained recurrent spontaneous abortions (URSA). The fixed or random effect pooled measure was selected based on the homogeneity test among studies that was evaluated with I². Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the association. In this meta-analysis, 14 studies with 1464 cases and 1247 controls corresponded to the inclusion criteria were included. Significant associations between 14 bp ins/del polymorphism and risk of URSA were observed in both dominant [random effect model (REM) OR = 1.469, 95% CI = 1.127-1.914] and codominant (REM OR = 1.195, 95% CI = 1.005-1.420) models. After excluding two articles that deviated from Hardy-Weinberg equilibrium in cases and sensitivity analysis, significant associations were also observed in dominant [fixed effect model (FEM) OR = 1.224, 95% CI = 1.020-1.470] and codominant (FEM OR = 1.158, 95% CI = 1.028-1.305) models. This meta-analysis suggests that the 14 bp ins HLA-G allele is associated with increased risk of URSA. The results are of importance to the clinical practice of URSA and infertility.