The clinical and ultrasound-based comparison between cesarean scar pregnancy and other lower uterine segment pregnancies with a history of cesarean section.

Objective: To compare the clinical and ultrasound characteristics of cesarean scar pregnancy (CSP) and other lower uterine segment pregnancies (LUSPs) to enable differential diagnosis of the two pathologies in the first trimester.Methods: A retrospective analysis of early pregnancies with a gestational sac located in the lower uterine segment with cesarean section history in our hospital from December 2011 to February 2018 was performed. According to the diagnoses, the patients were divided into the CSPs group and the other LUSPs group. The clinical and ultrasound features were compared.Results: A total of 38 patients were enrolled with 16 (42.1%) CSPs and 22 (57.9%) other LUSPs. Compared to the other LUSPs group, the CSPs group had thinner lower uterine myometrium (0.16 ± 0.11 cm versus 0.32 ± 0.14 cm, p = .000), larger maximum diameter of the gestational sac (5.14 ± 2.08 cm versus 3.77 ± 1.24 cm, p = .028); the distribution of the villous chorion sites (p = .001) and the main blood supply sites (p = .000) of the gestational sac were different between the two groups. Surgical bleeding volume during the termination of gestation was higher in the CSPs group than in the other LUSPs group (p = .028).Conclusion: Patients with CSPs and other LUSPs have different imaging characteristics on ultrasound. The prognosis of these patients also differs. Ultrasound feature is very useful in the differential diagnosis of these two clinical-mimicking pathologies.