OBJECTIVES: This study aims to develop and validate a prediction model for preterm birth in women with gestational diabetes mellitus (GDM). DESIGN: We conducted a retrospective study on women with GDM who gave birth at the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China, between November 2017 and July 2021. We divided 1879 patients into a development set (n = 1346) and a validation set (n = 533). The development set was used to construct the prediction model for preterm birth using the stepwise logistic regression mode...