Forest plot of the S680 influence variant on poor 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; In Livshyts 2009, the suffixes C and G indicate control women under 35 years old and over 35 years old, respectively. M-H: Mantel-Haenszel; CI: confidence interval; df: degree of freedom.