Abstract:ObjectiveTo investigate the value of real-time 3-dimensional （RT-3D） transvaginal ultrasound in evaluating the direction and frequency of endometrial peristalsis. MethodsTransvaginal RT-3D ultrasound was conducted in 122 non-menopausal female volunteers recruited in the Affiliated Hospital of Nanjing University of Chinese Medicine from December 2021 to May 2022. A total of 174 dynamic videos （2min） of sagittal and coronal planes of the uterus were obtained, which were played at 8-time speed and then evaluated by two observers for the direction and frequency of endometrial peristalsis. ResultsThere was a high degree of agreement between two observers in the assessment of peristaltic direction of the anterior and posterior walls on the sagittal plane and the left wall, right wall and uterine fundus on the coronal plane, with kappa values of 0.739, 0.768, 0.670, 0.687 and 0.614, respectively （P＜0.01）. There was no significant difference in the peristaltic frequency among the walls on the sagittal and coronal planes （P＞0.05）. There was a good agreement between two observers for the evaluation of peristaltic frequency at each wall ,with intra-group correlation coefficients of 0.888, 0.899, 0.828, 0.853 and 0.858, respectively for the anterior and posterior walls in the sagittal plane and the left wall, right wall and uterine fundus in the coronal plane （P＜0.01）. ConclusionRT-3D ultrasound can emerge the uterine peristalsis on the coronal plane and judge the peristaltic direction of the uterine fundus. The technique is highly reproducible and is a new and reliable method for evaluating the direction and frequency of uterine peristalsis.