Chen 2002a

Methods	Women 'randomly allocated' to 2 groups. Method of randomisation not reported
Participants	312 women attending the clinic in 4 family planning centres, Guangdong, China Women had regular menstrual periods and a single act of unprotected intercourse within 120 h of attending the clinic
Interventions	Mife 50 mg vs Mife 25 mg, single dose, orally
Outcomes	Observed number of pregnancies and changes in menstrual pattern
Notes	10 women excluded after recruitment, 2 lost to follow‐up Observed pregnancy/total number of women: Mife 50 mg 2/154; Mife 25 mg 4/148
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	Low risk	Exclusions and loss to follow‐up reported
Selective reporting (reporting bias)	Low risk	Planned outcome of pregnancy rate was reported
Other bias	Low risk	None detected