ObjectivesA classification system of ovarian ectopic pregnancies (OEP) could aid in their management. This study aimed to investigate the ultrasound classification and preoperative ultrasound diagnosis of OEP.MethodsThis retrospective case series study analyzed the clinical and ultrasound imaging data of 68 pregnant women diagnosed and confirmed with OEP at the Obstetrics and Gynecology Hospital affiliated with Tongji University between January 2015 and March 2023. The study focused on examining the ultrasound characteristics of different types of ovarian pregnancies and the accuracy of preoperative ultrasound diagnoses.ResultsThe study included 68 patients with a median age of 30 (22‐47) years. There were 43 cases (63.2%) of ruptured OEP and 25 (36.8%) of unruptured OEP. The unruptured cases were subclassified as embryonic sac type (n = 16) and heterogeneous mass type (n = 9). Preoperative ultrasound accurately diagnosed 19 cases (27.9%) of OEP, including 10 (62.50%) of the embryonic sac type, 4 (44.44%) of the heterogeneous mass type, and 5 (11.63%) of the ruptured type. Preoperative ultrasonography showed that embryonic sac type OEP was characterized by an intra‐ovarian cystic structure with a distinctive hyperechoic ring and, in some cases (8 out of 16), the presence of embryonic buds and/or yolk sacs. Ruptured OEP was characterized by mixed masses in the pelvic cavity with minimal or significant free pelvic fluid, an unclear boundary between the mass and the ovary, and limited or no vascularity.ConclusionsUltrasound may be used to determine the type of OEP preoperatively, with a higher diagnostic yield for the embryonic sac subtype. Preoperative ultrasonographic classification may enhance the preoperative diagnosis of OEP.