Yang X, et al. - A retrospective cohort study was conducted to evaluate the relationships between pre-pregnancy body mass index (BMI) and neonatal outcomes in women undergoing autologous frozen-thawed embryo transfer (FET). Researchers recruited a total of 16,240 women with singleton deliveries achieved by autologous FET. Pre-pregnancy BMI affected neonatal outcomes of singletons among women undergoing FET. The results of this study exhibited that BMI in Asian categories for overweight and obese exhibited significant increases in PTB, macrosomia, and LGA; early PTB and very LBW only elevated in obese cases. An association was found between underweight status and elevated risk of SGA. No relationship was observed between pre-pregnancy BMI and birth defects in FET cycles.