Crossover Sign in Cesarean Scar Ectopic Pregnancy
What is the Crossover Sign?
The "crossover sign" refers to a specific ultrasound finding in cesarean scar ectopic pregnancy (CSEP) where the gestational sac is visualized anterior to the uterine cavity, embedded within the cesarean scar tissue, with the bladder appearing to "cross over" or sit anterior to the pregnancy implantation site. This distinguishes a true scar pregnancy from a low-lying intrauterine pregnancy or cervical ectopic.
Management Approach
When a cesarean scar ectopic pregnancy is diagnosed by ultrasound (including the crossover sign), expectant management should be avoided due to high risk of uterine rupture and life-threatening hemorrhage, and treatment should proceed with either operative resection or intragestational methotrexate. 1
Primary Treatment Options
The Society for Maternal-Fetal Medicine provides the following evidence-based recommendations for CSEP management:
Surgical Management (Preferred for Definitive Treatment)
Operative resection via transvaginal or laparoscopic approaches should be considered as first-line surgical treatment when feasible, as these methods remove both the pregnancy and scar tissue, reducing future morbidity and promoting fertility 1, 2
Ultrasound-guided uterine aspiration is an acceptable surgical option for hemodynamically stable patients 1
Sharp curettage alone must be avoided due to high risk of catastrophic hemorrhage from the vascularized scar tissue 1
Surgical removal of the pregnancy and scar tissue has shown superior outcomes compared to methods that leave scar tissue intact 2
Medical Management
Intragestational methotrexate (injected directly into the gestational sac) should be used for medical treatment, with or without adjunctive therapies such as uterine artery embolization 1, 3
Systemic methotrexate alone should NOT be used as monotherapy for CSEP, as it has unacceptably high failure rates requiring subsequent intervention 1, 4
Medical management frequently requires additional treatment with repeat medication doses or surgical intervention 2
Combined Approaches
Uterine artery embolization can be combined with methotrexate or surgical approaches to reduce hemorrhage risk, though multiple embolizations may be necessary 3
The combination approach is particularly useful when initial treatment fails or bleeding complications arise 3
Critical Management Principles
Expectant management is contraindicated - it carries the highest probability of severe morbidity including hemorrhage, uterine rupture, and potential maternal mortality 1, 2, 5
Hemodynamic stability determines urgency - unstable patients require immediate surgical intervention, while stable patients can undergo planned treatment with appropriate counseling 6, 1
Early diagnosis and treatment are essential to prevent complications and preserve fertility 3, 5
Follow-Up Considerations
Hysteroscopic evaluation 3-4 months post-treatment may reveal persistent uterine defects within the cesarean scar that require documentation 3
Patients must be counseled about risks of future pregnancy and offered effective contraception, including long-acting reversible contraception or permanent sterilization 1
Serial β-hCG monitoring is essential after any treatment modality to confirm resolution 6
Special Circumstance: Patient Declines Treatment
If a patient refuses treatment and continues the pregnancy, planned repeat cesarean delivery between 34 0/7 and 35 6/7 weeks of gestation is mandatory due to extreme risk of catastrophic complications 1