What is the management of a scar site pregnancy?

Management of Cesarean Scar Ectopic Pregnancy

The management of cesarean scar ectopic pregnancy (CSEP) requires prompt intervention with surgical approaches being most effective, as expectant management is generally not recommended due to high risks of maternal morbidity and mortality.

Diagnosis and Classification

• CSEP is defined as implantation of a pregnancy in a cesarean section scar or niche, which is becoming more common as cesarean delivery rates rise worldwide 1
• Transvaginal ultrasound is the primary diagnostic modality, which may show:
  • Gestational sac located at the site of previous cesarean scar 1
  • Empty uterine cavity and cervical canal 2
  • Thin or absent myometrium between the gestational sac and bladder 3
  • Presence or absence of cardiac activity (affects prognosis) 4

Treatment Options

Surgical Management (Recommended First-Line)

• Suction evacuation has the highest success rate (91.5%) and should be considered as first-line treatment for CSEP 5
• Other effective surgical options include:
  • Operative resection via transvaginal or laparoscopic approaches 2
  • Ultrasound-guided uterine aspiration 2
• Sharp curettage alone should be avoided due to risk of hemorrhage and uterine perforation 2
• Surgical management is most effective when performed early in the first trimester 5

Medical Management (Second-Line)

• Intragestational (local) methotrexate may be used, with or without other treatment modalities 2
• Systemic methotrexate alone should NOT be used as it has:
  • Lower success rate (59.4%) 5
  • Higher complication rates 5
  • Substantial risk of treatment failure 2
• Local injection of potassium chloride may be considered for CSEP with cardiac activity but has lower efficacy than surgical options 5

Balloon Management

• Balloon tamponade techniques have shown reasonable success (approximately 90%) 5
• This approach may be useful when surgical expertise is limited or as an adjunct to other treatments 5

Special Considerations

• Anesthesia for surgical management after 20 weeks should include:

  • Left uterine displacement 1
  • Maintenance of adequate maternal oxygenation 1
  • Optimization of uteroplacental perfusion 1

• Monitoring requirements:

  • If fetus is previable: auscultation of fetal heart tones before and after surgery 1
  • If fetus is viable: continuous electronic fetal heart rate and contraction monitoring 1

Risks of Expectant Management

• Expectant management is generally NOT recommended due to high risk of:

  • Major hemorrhage 2
  • Uterine rupture 3, 2
  • Development of placenta accreta spectrum disorders 1, 4
  • Hysterectomy 3, 2

• Limited cases where expectant management might be considered:

  • Absent fetal heart activity with rapidly decreasing β-hCG levels 6
  • Relatively thick myometrial layer at implantation site 4
  • However, even in these cases, close monitoring is essential 6

Follow-up and Future Pregnancy Considerations

• After treatment, patients should be monitored with serial β-hCG measurements until levels normalize 3
• Patients should be counseled about:
  • Risks of recurrent CSEP in future pregnancies 2
  • Effective contraceptive methods including long-acting reversible contraception 2
  • Potential need for permanent contraception in high-risk cases 2

Complications and Management

• If severe hemorrhage occurs:

  • Uterine artery embolization may be required 4
  • Hysterectomy may be necessary in cases of uncontrolled bleeding 3

• For patients who choose to continue the pregnancy despite risks:

  • Delivery should be planned between 34-36 weeks 2
  • Cesarean delivery is indicated 1
  • High risk of placenta accreta spectrum must be anticipated 1