Qian 1999

Methods	Women 'randomly allocated' to 3 groups. Method of randomisation not reported
Participants	252 women attending a family planning clinic in Shenzhen, China. Women had regular menstrual periods and attended the clinic within 72 h of a single act of unprotected intercourse
Interventions	Mife 150 mg orally, single dose vs Mife 50 mg vs Mife 25 mg
Outcomes	Observed number of pregnancies, side effects and changes in menstrual pattern
Notes	Post‐randomisation exclusion or loss to follow‐up not reported Observed pregnancy/expected pregnancy/total number of women: Mife 150 mg 1/7/86; Mife 50 mg 0/8/82; Mife 25 mg 1/8/84
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Mentioned randomisation but description not adequate
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not mentioned
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Post‐randomisation exclusion or loss to follow‐up not reported
Selective reporting (reporting bias)	Low risk	Reported planned outcomes
Other bias	Low risk	None detected