Forest plot of the S680 influence variant on hyper ovarian response. Black diamond denotes the pooled OR. Blue squares indicate the OR in each study, with square sizes directly proportional to the weight contribution (%) of the study. Horizontal lines represent 95% confidence intervals. Note: In Boudjenah et al. , the suffixes A and S indicate overall population and homogeneous subgroup, respectively; . M-H: Mantel-Haenszel; CI: confidence interval; df: degree of freedom.