Lai 2004

Methods	Women 'randomly allocated' to 2 groups. Method of randomisation not reported
Participants	300 women attending the gyn clinic in a general hospital, Qinghai, China. Women had regular menstrual periods and a single act of unprotected intercourse within 120 h of attending the clinic
Interventions	Mife 10 mg vs Mife 25 mg, single dose, orally
Outcomes	Observed number of pregnancies, side effects and changes in menstrual pattern
Notes	20 women excluded after recruitment, 1 loss to follow‐up Observed pregnancy/expected pregnancy/total number of women: Mife 10 mg 2/13/149; Mife 25 mg 2/11/130
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	Post‐randomisation exclusion and loss to follow‐up reported
Selective reporting (reporting bias)	Low risk	Reported planned outcomes
Other bias	Low risk	None detected