Statistical analysis
Results are presented either as the mean ± standard deviation (SD), percentages or absolute numbers. The continuous variables were expressed as mean ± SD. Whereas categorical variables (e.g., clinical outcomes and type of infertility) were presented as percentage (%) and absolute numbers (n). The analysis of all outcomes was on an intention-to-treat basis. To address potential confounding variables, multivariable logistic regression analysis was used to assess whether clinical results, particularly clinical pregnancy rate was affected by age, BMI, basal FSH level, AMH level and AFC count, as well as stimulation protocol. A probability value of <0.05 was considered statistically significant. SPSS software (version 22.0; SPSS Inc, Chicago, IL) was used to perform all statistical analyses.