Abstract

The present meta-analysis was performed to investigate the association of promoter region polymorphisms at IL-6 and IL-18 genes with recurrent pregnancy loss (RPL) risk. An electronic search of the PubMed, Embase, ISI Web of Knowledge and CNKI databases was performed to identify eligible studies up to May 30, 2019. A total of 31 case-control studies were finally selected. Significant associations with the risk of RPL were detected for the IL-6 -174 G > C, -634 G > C and IL-18 -137 G > C polymorphisms in overall population. Further, subgroup analyses by ethnicity revealed that the IL-6 -174 G > C and -634 G > C polymorphisms were significantly associated with risk of RPL risk in Asians. Our results suggest that the IL-6 -174 G > C, -634 G > C and IL-18 -137 G > C polymorphisms may contribute to the susceptibility of RPL. The IL-18 -607 C > A polymorphism does not appear to influence the development of RPL.