Zhuang 2009.

Study characteristics
Methods	Randomization using sealed and numbered envelopes, with a randomization table
Participants	72 women with CSP
Interventions	Infusion of MTX intravenously (50 mg/m2 body surface area) (35 cases, age: 32.88 ± 0.98y) vs UAE (37 cases, age: 32.23 ± 0.65y) suction curettage performed when β‐hCG decreased to < 50 mIU/mL in MTX group suction curettage performed after 24 hours in UACE group
Outcomes	Primary outcomes: success after initial treatment complications Secondary outcomes: adverse effects (MTX group including abnormal liver function and severe vomiting; UAE group including fever and pain and 1 readmitted woman) blood loss hospital stay
Notes	Data of primary outcome (serum β‐hCG level) not shown
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomly assigned in a 1:1 allocation ratio using a randomization table."
Allocation concealment (selection bias)	Low risk	Quote: "Randomization was conducted via a system of sealed and numbered envelopes."
Blinding of participants and personnel (performance bias) All outcomes	High risk	No data available for this specific type of bias, and blinding was not possible with this methodology.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No data available for this specific type of bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Unclear risk	Insufficient information to permit judgement.
Other bias	Unclear risk	Insufficient information to assess whether an important risk of bias existed.

β‐hCG: β‐human chorionic gonadotropin; CSP: caesarean scar pregnancy; MTX: methotrexate; PVA: polyvinyl acetate; UACE: uterine arterial chemoembolization; UAE: uterine arterial embolization.