Background: Caesarean-scar pregnancy is a rare form of ectopic pregnancy in which implantation occurs within the myometrial defect of a previous caesarean section scar. Its incidence has increased with rising caesarean delivery rates and improved early pregnancy imaging. Delayed diagnosis may result in severe maternal morbidity, including uterine rupture, massive hemorrhage, placenta accreta spectrum, and potential loss of fertility. 

Case Presentation: We report a case of a woman in her early thirties presenting with pelvic pain, fever, and persistent low-level β-hCG, initially managed as infected retained products of conception. Laboratory findings demonstrated raised inflammatory markers, and empirical intravenous antibiotics were commenced. Subsequent transvaginal ultrasound identified a highly vascular mass at the site of the previous caesarean-section scar with an irregular hemorrhagic sac-like structure and absent myometrial covering, consistent with a failed caesarean-scar pregnancy. Due to clinical deterioration and concern regarding possible uterine rupture, surgical management was undertaken. Histopathology confirmed products of conception, and serial β-hCG levels declined appropriately during follow-up. 

Discussion: This case highlights the diagnostic challenge of caesarean-scar pregnancy when clinical features overlap with more common early pregnancy complications. Transvaginal ultrasound with Doppler assessment remains the cornerstone of diagnosis and is essential for timely management. 

Conclusion: Caesarean-scar pregnancy should be considered in women with previous caesarean delivery presenting with pelvic pain, abnormal bleeding, or persistent β-hCG levels. Early recognition and specialist imaging are critical to prevent life-threatening complications and optimize patient outcomes.