Meta-analysis of association between il-6-174 g/c polymorphism and female infertility related disorders

•Whether IL-6-174 G/C polymorphism can be considered as a potential genetic marker for early identification of female related infertility disorder was analyzed using meta-analysis.•Significant heterogeneity was attained across the studies which could be explained by the effect of factors like ethnicity, country, environment, life style, habits, age and BMI.•Under subgroup analyses, favourable association was seen for PCOS under allele and dominant model compared to other disorders selected for the analysis.•More studies with adequate sample size studying other polymorphisms of IL-6 as well as other female infertility disorders are required to arrive at a definite conclusion. Female infertility continues to increase in prevalence annually and factors causing it need to be researched. As IL-6-174 G/C polymorphism is known to alter the plasma levels of IL-6, abnormal levels of IL-6 found in infertile females could be due to genetic reasons. With the understanding of the importance of IL-6 in reproductive physiology, several individual studies done so far to find the association of this polymorphism with female infertility related disorders were systematically combined for meta-analysis. Articles were searched using electronic data base sources and were included based on specific criteria. Finally, eight articles which includes polycystic ovarian syndrome (PCOS; n = 4), endometriosis (n = 3) and tubal damage (n = 1) were selected for the analysis. Results showed statistically significant heterogeneity across studies under the allele model (p < 0.0001, I2 = 78 %) and dominant model (p < 0.00001, I2 = 82%) but not under recessive model (p = 0.31, I2 = 16%). This difference could be possibly due to variation in ethnicity, lifestyle, age or BMI related factors. The pooled odds ratio under the three genetic models were 0.87(CI = 0.75-1.02), 0.77 (CI = 0.63-0.94) and 1.05 (CI = 0.76-1.46) respectively. Sub group analysis showed statistical significant (P < 0.01) for PCOS under allele and dominant model, but not for endometriosis and tubal damage. By this meta-analysis, we can say that IL-6-174 G/C polymorphism can be considered as a potential genetic marker for PCOS but not for endometriosis and tubal damage disorders. However, more studies with adequate sample sizes are required to be done in endometriosis, tubal disease and other female infertility disorders to arrive at a definite conclusion.