Is a history of cesarean section a predictive factor for the failure of medical management in spontaneous abortion?

OBJECTIVES: This study aims to evaluate the risk factors for failure of medical treatment for first-trimester spontaneous abortion and the specific role of prior cesarean delivery (CD). METHODS: This retrospective cohort study analyzed data from patients who underwent medical management of first-trimester spontaneous abortion using mifepristone and misoprostol at a tertiary medical center between 2019 and 2022. Data collected included demographic, clinical, and sonographic parameters, with comparisons made between patients with successful and unsuccessful treatment outcomes. Univariable and multivariable logistic regression analyses were conducted. RESULTS: Among the 716 patients included in the study, treatment failure was observed in 29.5%. In multivariable analysis, prior CD was independently associated with an increased risk of treatment failure (aOR 1.97; 95%CI 1.25-3.12; p = 0.004). Additionally, advanced gestational age was also associated with an increased likelihood of failure (aOR 1.02 per day; 95%CI 1.00-1.03; p = 0.009). In subgroup analyses, patients with prior CD had higher failure rates compared with those without prior CD (43.2% vs 27.4%, p = 0.002). Among patients without prior CD, gestational age > 70 days was associated with higher failure rates compared with ≤ 70 days (35.2% vs 24.3%, p = 0.006). In this subgroup (no prior CD and gestational age ≤ 70 days), the presence of bleeding during treatment was associated with lower failure rates (12.5% vs 25.6%, p = 0.001). CONCLUSION: Prior cesarean delivery was independently associated with an increased risk of treatment failure following medical management of first-trimester spontaneous abortion. Advanced gestational age was also associated with increased failure rates. Further studies are needed to refine treatment protocols and explore approaches for patients with prior CD.