Cesarean Scar Pregnancy: Ultrasound Criteria and Differential Diagnosis with Cervical Pregnancy
Ultrasound Criteria for Cesarean Scar Pregnancy (CSP)
According to diagnostic criteria published in Ultrasound in Obstetrics & Gynecology (ISUOG, 2024), the following conditions must be satisfied to establish a diagnosis of CSP:
- empty uterine cavity and cervical canal with absence of gestational sac;
- gestational sac in the anterior wall of the isthmic segment, with or without fetal cardiac activity;
- presence of myometrial defect between the bladder and the gestational sac;
- presence of pronounced (sometimes abundant) vascular pattern in the cesarean scar region.
Vascularization of the gestational sac is assessed by semiquantitative method using color Doppler mapping.
Distinction from Cervical Pregnancy
The key differential feature of CSP according to the aforementioned criteria is the localization of the gestational sac in the anterior wall of the isthmic segment (in the scar region) with an empty cervical canal, as well as the presence of a myometrial defect between the bladder and the gestational sac. Detailed comparative criteria specifically for cervical pregnancy are not provided in the supplied fragments [to be clarified].
Significance of Timely Diagnosis
CSP is among the diagnoses that must not be missed (Kennedy A, et al. Radiographics, 2024). A history of cesarean delivery is associated with risk of subsequent ectopic pregnancy and placentation complications (O'Neill SM, et al. BJOG, 2013; Silver RM. Semin Perinatol, 2012). To standardize reporting terminology, a CSP reporting system in early pregnancy has been proposed, developed using a modified Delphi method (Jordans IPM, et al. UOG, 2022).
Management Strategy
A systematic review and meta-analysis of CSP outcomes with expectant management has been published (Cali G, et al. UOG, 2018). Specific threshold values and algorithms for selecting management strategy are not detailed in the supplied fragments [to be clarified].
Frequently asked questions
What are the four ultrasound criteria necessary for CSP diagnosis?
Empty uterine cavity and cervical canal without gestational sac; gestational sac in the anterior wall of the isthmic segment; myometrial defect between the bladder and the sac; pronounced vascular pattern in the scar region (ISUOG, 2024).
How is vascularization of the gestational sac assessed in CSP?
By semiquantitative method using color Doppler mapping (ISUOG, 2024).
What distinguishes CSP from cervical pregnancy on ultrasound?
In CSP, the gestational sac is localized in the anterior wall of the isthmic segment (scar region) with an empty cervical canal and a myometrial defect between the bladder and the sac. Detailed criteria for cervical pregnancy are not provided in the fragments [to be clarified].
Is there a standardized reporting system for CSP?
Yes, a CSP definition and reporting system in early pregnancy has been proposed, developed using a modified Delphi method (Jordans IPM, et al. UOG, 2022).
Is expectant management possible in CSP?
A systematic review and meta-analysis of CSP outcomes with expectant management has been published (Cali G, et al. UOG, 2018); specific criteria for selecting management strategy are not provided in the fragments [to be clarified].