Overweight and obesity determined by body mass index criteria for Asian populations adversely affect assisted reproductive outcomes among Chinese women with polycystic ovary syndrome

Background Obesity is a common feature in women with polycystic ovary syndrome (PCOS) and is associated with multiple adverse reproductive outcomes. However, the impact of overweight and obesity on reproductive outcomes of women with PCOS who underwent in vitro fertilization-embryo transfer (IVF-ET) is currently controversial and appropriate body mass index (BMI) levels differ across ethnic groups. Methods This was a retrospective study including 1066 women with PCOS receiving IVF treatment at our institution between January 2018 and June 2021, among whom 960 underwent their first fresh or frozen embryo transfer. Participants were categorized according to BMI cut-off values proposed by the World Health Organization for Asian populations: normal weight (BMI