Yang 2001

Methods	Women 'randomly allocated' to 4 groups. Method of randomisation not reported
Participants	358 healthy women recruited into the study from clinics of MCH hospital in Guangzhou, China Included women with regular menstrual periods, aged 17‐46 years, who had attended the clinic within 72 h of a single act of unprotected intercourse and they were willing to use condom for further acts of unprotected coitus during that cycle Excluded women on hormonal contraception in the current cycle and those with uncertain dates of last menstrual period
Interventions	Mife 25 mg twice, 12 h apart vs anordrin 7.5 mg, twice, 12 h apart vs danazol 400 mg, twice, 12 h apart
Outcomes	Observed number of pregnancies, side effects and changes in menstrual pattern
Notes	Loss to follow‐up not reported Observed pregnancy/expected pregnancy/total number of women: Mife 1/14/121; anordrin 4/13/117; danazol 5/14/120
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	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