We observed the effect of body mass index (BMI) on pregnancy outcomes in Chinese patients undergoing assisted reproductive treatment (ART). All the patients were divided into polycystic ovary syndrome (PCOS) group and non-PCOS group, and then according to BMI, each group was subdivided into 6 subgroups: group 1 (BMI < 18 kg/m2), group 2 (18-20 kg/m2), group 3 (20-22 kg/m2), group 4 (22-24 kg/m2...
