Sun 2007

Methods	Women randomly allocated to 2 groups. Method of randomisation not reported
Participants	1100 women attending in a village clinic, Miyun county, Beijing, China. Women had regular menstrual periods and a single act of unprotected intercourse within 72 h of attending the clinic
Interventions	LNG 0.75 mg, 2‐dose, 12 h apart, orally vs LNG‐COC 4 tablets (total ethinyl oestradiol 0.12 mg and LNG 0.6 mg), 2‐dose, 12 h apart, orally
Outcomes	Observed number of pregnancies, side effects and changes in menstrual pattern
Notes	Observed pregnancy/total number of women: LNG 11/557 (user's failure 4); LNG‐COC: 14/553 (user's failure 6)   Side effects: LNG: nausea and vomiting 100/557; dizziness and fatigue 39/557 LNG‐COC: nausea and vomiting 227/553; dizziness and fatigue 45/553  Changes in menstrual pattern:  Early: LNG 76/557; LNG‐COC 68/553  Delay: LNG 66/557; LNG‐COC 55/553 Spotting: LNG 61/557; LNG‐COC 73/553
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