Patient characteristics
A total of 472 (6.5 %) were excluded due to lack of CLB results; therefore, of the 7701 women eligible for the study, 7229 women were included in the analysis (Fig. 1). The participants were divided into two BMI groups (normal BMI and high BMI); the baseline characteristics are summarized in Table 1. Overall, 6174 women had normal weight (18.5 ≤ BMI ≤ 24.9), while 1055 women were considered overweight and obese (BMI ≥ 25). There were no significant differences in the type and etiology of infertility, fertilization method, and antral follicle count between the two BMI groups. The duration of infertility (3 vs 3, Z= 5.594, p < 0.001) and basal FSH (6.66 vs 6.9, Z= -5.337, p < 0.001) were significantly longer and lower in the high BMI group than in the normal group, respectively.