Mahran 2015.

Study characteristics
Methods	Randomised controlled trial, 2 groups, set in Minia Infertility Research Unit, Egypt June 2012 to May 2014 Number of participants randomised: 200 Number of participants analysed: unknown
Participants	Inclusion and exclusion criteria: not described Cause of infertility: unexplained
Interventions	Intervention group: endometrial scratching performed once on Day 21 of the cycle preceding the intrauterine insemination (IUI) cycle Control group: "no intervention" Degree of endometrial injury: pipelle Timing of endometrial injury: in the luteal phase (on Day 21) of the cycle preceding the IUI cycle Study length: 1 cycle Type of conception: IUI
Outcomes	Reported in the paper: Clinical pregnancy (not defined, only percentages were given; therefore data could not be used in the meta‐analysis)
Notes	Only a conference abstract was available Funding source: not described Conflicts of interest: not described Trial registration: not found Author correspondence was undertaken, but we did not receive a response
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation method was not described
Allocation concealment (selection bias)	Unclear risk	Abstract did not report whether allocation concealment was performed
Blinding of participants (performance bias)	High risk	Abstract did not report blinding of participants, and it was unlikely; lack of participant blinding is anticipated to introduce performance bias
Blinding of personnel (performance bias)	High risk	Abstract did not report any blinding of personnel
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Abstract did not report blinding of outcome assessors, and it was unlikely; outcomes were unlikely to be influenced by lack of blinding, as there were no patient‐reported outcomes
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Abstract did not report any information about missing data
Selective reporting (reporting bias)	Unclear risk	We did not find a trial registration number or protocol
Other bias	Unclear risk	Information is insufficient to show whether an important risk of bias exists