Objective To investigate the symptoms of gestational diabetes mellitus (GDM) patients in late pregnancy, extract symptom clusters, construct a symptom network, analyze core and bridge symptoms, and provide a reference for symptom management of GDM in late pregnancy. Methods A cross-sectional study was conducted among 444 GDM patients from January to July 2025.The general information questionnaire and the Memorial Symptom Assessment Scale were used for data collection.Symptom clusters were extracted by exploratory factor analysis; R software was used to visualize cluster symptom relationships and to calculate the expected influence coefficients of nodes, thereby determining core and bridge symptoms. Results The symptoms with the highest incidence and severity scores were increased nocturnal urination (92.12%), poor sleep quality (91.57%), and pain (90.77%).Five symptom clusters were identified:sleep-disorder symptom cluster, psychosomatic symptom cluster, somatic symptom cluster, edema symptom cluster, image-related symptom cluster; cumulative variance contribution 59.087%.Anxiety (rEI=1.319) was identified as a core symptom in the network, whereas subjective swelling (rbEI=0.928) served as a bridge symptom. Conclusion GDM patients experience multiple symptoms in late pregnancy; healthcare staff should promptly assess these symptoms, develop and implement targeted interventions, reduce symptom burden, and improve patients′ quality of life.