Han 1999a

Methods	Women 'randomly allocated' into 2 groups in a 2:1 ratio. Method of randomisation not reported
Participants	214 women aged 21‐45 years attending the obs/gyn clinic Chao Yang Hospital, Beijing, China. Women had regular menstrual periods and unprotected intercourse within 72 h of attending the clinic
Interventions	LNG 0.75 mg, 2 doses, 12 h apart vs Mife 25 mg, single dose, orally
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 of women: LNG 5/13/144; Mife 1/5/70
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 exclusions or loss to follow‐up not reported
Selective reporting (reporting bias)	Low risk	Planned outcome was reported
Other bias	Low risk	None detected