Elevated gestational weight gain (GWG) during pregnancy among women diagnosed with gestational diabetes mellitus (GDM) is correlated with an increased instance of large for gestational age (LGA) and macrosomia. However, it remains uncertain whether managing weekly GWG following a GDM diagnosis positively impacts fetal birth weight.Our study found that GWG following GDM diagnosis correlates positively with the risk of LGA and macrosomia among all body mass index (BMI) subgroups, especially for overweight and obese women.The results of this research highlight the importance of enforcing a more stringent regulation on GWG on a weekly basis for overweight and obese women diagnosed with GDM, particularly when considering neonatal growth.Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2023.