Askalani 1987.

Methods	'randomly allocated' women to 2 groups. The numbers enrolled in 2 groups were 2:1 between treatment and control. Although 2:1 randomisation was not specifically mentioned, the trial was included because it is explicitly stated that the allocation was random No details of allocation concealment or other methodological aspects were mentioned
Participants	300 women attending the family planning clinic of the Al‐Azhar University, Cairo, Egypt Included women who had had unprotected intercourse around the time of ovulation and attended the clinic within 4 days of unprotected intercourse
Interventions	Cu‐IUD (Cu‐T 200) vs control (no treatment)
Outcomes	Pregnancy rates
Notes	No loss to follow‐up or exclusions were reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not explained
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not mentioned
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Blinding not mentioned or method explained
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Any losses to follow‐up or exclusion were not reported
Selective reporting (reporting bias)	Low risk	Planned outcome of pregnancy rate was reported
Other bias	Low risk	None detected