Zhang 2012

Methods	Women randomly allocated into 2 groups. Randomised digital table method was used for randomisation
Participants	130 women attending a ob/gyn department in a general hospital in Shanghai, China. Women had regular menstrual periods and a single act of unprotected intercourse within 72 h of attending the hospital
Interventions	Mife 20 mg, single dose, orally 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 exclusion and loss to follow‐up not reported Observed pregnancy/total number women: Mife 2/65; LNG 2/65
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised digital table method was used for randomisation
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	No mention of post‐randomisation exclusion and loss to follow‐up
Selective reporting (reporting bias)	Low risk	Reported planned outcomes
Other bias	Low risk	None detected