Lin 2000

Methods	Double‐blind randomised trial. Method of randomisation not reported
Participants	120 women attending a family planning clinic in Tianjing, China. Women had regular menstrual periods and attended the clinic within 72 h of a single act of unprotected intercourse
Interventions	Mife 10 mg + placebo, 12 h apart vs LNG 0.75 mg, 2 doses, 12 h apart
Outcomes	Observed number of pregnancies, side effects and changes in menstrual pattern
Notes	Post‐randomisation exclusions or loss to follow‐up not reported Observed pregnancy/expected pregnancy/total number women: Mife + placebo 0/5/60; LNG 0/5/60
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not reported
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not mentioned
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blind
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Post‐randomisation exclusions or loss to follow‐up not reported
Selective reporting (reporting bias)	Low risk	Reported planned outcomes
Other bias	Low risk	None detected