Soliman 2017.

Study characteristics
Methods	Randomised controlled trial, 2 groups, set in Cytogenetic and Endoscopy Unit, Zagazig University Hospital, Egypt March 2013 to May 2015 Number of participants randomised: 226 Number of participants analysed: 212
Participants	Inclusion criteria: female; aged 19 to 37 years; normal basal hormonal profile (follicle‐stimulating hormone (FSH) and luteinising hormone (LH): 3 to 10 mIU/mL and 1.8 to 8.5 mIU/mL, respectively); normal uterine cavity as assessed by hysterosalpingography (HSG); patent tubes; normal semen analysis (however, couples with mild male factor infertility were eligible: this was defined as "2 or more semen analyses with 1 or more items below the 5th centile as defined by the World Health Organization (WHO) 2010") Exclusion criteria: unilateral tubal patency; history of ovarian hyperstimulation syndrome (OHSS); diminished ovarian response; endometriosis; multiple female factors Cause of infertility: unexplained infertility, mild male factor
Interventions	Intervention group: endometrial scratching was planned on Day 7 of the stimulated intrauterine insemination (IUI) cycle Control group: no endometrial scratching Both groups: ovarian stimulation was performed using clomiphene citrate 100 mg daily from Cycle day 2 for 5 days and human menopausal gonadotropin (hMG) (Menogon) 75 IU/d from Day 7 until the leading follicles reached a mean diameter ≥ 17 mm and the endometrium had thickness ≥ 8 mm with triple‐line pattern. Ovulation was triggered by hCG 10,000 IU (Choriomon). IUI was performed after 36 hours. Luteal phase support was provided with vaginal progesterone suppositories 400 mg (Prontogest) from the day of IUI and was continued for 2 weeks Degree of endometrial injury: embryo mucus aspiration catheter (Rocket medical) with the catheter sheath tip cut obliquely Timing of endometrial injury: follicular phase (on Day 7) of the stimulated IUI cycle Study length: 1 cycle Type of conception: IUI
Outcomes	Reported in the paper: Clinical pregnancy (presence of an intrauterine gestational sac with a heartbeat 3 weeks after a positive pregnancy test) Ongoing pregnancy rate (subtracting miscarriage from clinical pregnancy rate) Miscarriage (spontaneous loss of a foetus before the 20th week of pregnancy)
Notes	Funding source: study authors declare that there was no financial support for this paper Conflicts of interest: conflicts of interest not described but study authors declare that there was no financial support for this paper 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)	Low risk	Quote: "patients were divided randomly by using random table (computer), software Open Epi version 3.21 into approximately two groups"
Allocation concealment (selection bias)	Unclear risk	Quote: "...allocation concealment concentrated on preventing selection and confusing biases" Study did not report how allocation concealment was performed
Blinding of participants (performance bias)	High risk	Study 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	Study did not report any blinding of personnel
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Study did not report blinding of outcome assessors, and it was unlikely; however outcomes were unlikely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing outcome data were balanced in numbers with similar reasons for missing data across intervention groups; therefore the study was rated at low risk of attrition bias
Selective reporting (reporting bias)	Unclear risk	We did not find a trial registration number nor a protocol
Other bias	Low risk	We did not identify any other sources of bias