Objective: To compare the complication rates after uterine artery chemoembolization (UACE) followed by dilation and curettage (D&C) guided by different types of monitoring for treatment of cesarean scar pregnancy (CSP). Methods: A randomized controlled trial was undertaken of women with CSP attending a hospital in Wuhan, China, between June 1, 2010, and June 30, 2014. Using sealed opaque envelopes containing random numbers, participants were randomly allocated to undergo D&C with hysteroscopy monitoring, ultrasonography monitoring, or no monitoring. Participants and investigators were masked to group assignment. The primary outcome was the number of participants with complications at 2 months of follow-up after D&C. Analyses were by intention to treat. Results: Among 144 participants, 48 were assigned to hysteroscopy monitoring, 44 to ultrasonography monitoring, and 52 to no monitoring. Complications were noted for 1 (2.1%) patient in the hysteroscopy group, 2 (4.5%) in the ultrasonography group, and 12 (23.1%) in the no monitoring group (P=0.001). Conclusion: Hysteroscopy or ultrasonography monitoring of D&C after UACE for CSP treatment can decrease the complication rate. ClinicalTrials.gov: NCT02357095. (C) 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.