Hamdi 2019.

Study characteristics
Methods	Randomised controlled trial, 2 groups, set in Al‐Zahra Hospital, Iran April 2016 to March 2017 Number of participants randomised: 150 Number of participants analysed: 150
Participants	Inclusion criteria: mild ovulation disorder; mildly abnormal semen parameters (sperm counts ≥ 15 million/mL, sperm motility > 20%, normal sperm morphology > 15%); mild endometriosis and infertility with unknown etiology Exclusion criteria: age > 35 years; uterine masses like submucosal leiomyoma; previous diagnosis of moderate to severe pelvic endometriosis on abdominal or pelvic sonography; hysteroscopy or laparoscopy; unilateral obliteration of fallopian tube; body mass index (BMI) > 35 kg/m²; severe abnormalities in seminal fluid Cause infertility: mild male infertility, mild ovulation disorder, unexplained infertility
Interventions	Intervention group: endometrial scratching between Cycle day 1 and 5 in the same cycle as intrauterine insemination (IUI) Control group: no endometrial scratching Both: ovarian stimulation with 100 mg clomiphene for 5 days starting on Cycle day 3, 4, or 5. In addition, follicle‐stimulating hormone (FSH) 75 units (Gonal‐F) was used for 3 to 5 days, starting between Cycle days 7 and 10. Human chorionic gonadotropin (hCG) was used to trigger ovulation when follicles were 18 to 20 mm, and IUI was performed 36 hours later. Luteal phase support was performed with 10 mg dydrogesterone (Duphaston) for 14 days Degree of endometrial injury: IUI catheter or pipelle Timing of endometrial injury: between Cycle days 1 and 5 in the same cycle as IUI Study length: 1 cycle; if pregnant, women were followed up until 3 months of pregnancy Type of conception: IUI
Outcomes	Reported in the paper: Clinical pregnancy (in the paper, stated as "successful pregnancy" and defined as "evaluated by beta human chorionic gonadotropin (β‐hCG) titers and sonography") Abortion (not defined)
Notes	Funding source: not reported Conflicts of interest: study authors declared no conflict of interest Trial registration: IRCT2016110213566N7 (retrospectively registered) Author correspondence was undertaken; however 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	Study authors did not describe whether allocation concealment was performed
Blinding of participants (performance bias)	High risk	Study did not report blinding of participants, and it was unlikely; we anticipate that lack of participant blinding introduced 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 as there were no patient‐reported outcomes
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No description of missing data was provided in the paper
Selective reporting (reporting bias)	Unclear risk	Trial was registered retrospectively
Other bias	Unclear risk	Quote: "among the infertile couples referred to infertility treatment clinic of Al‐Zahra hospital (from April 2016 to March 2017), 150 cases were chosen randomly to enter this randomized clinical trial"  It is unclear whether only enrolment or both enrolment and follow‐up took place during this period Quote: "the patients were followed‐up for 3 months to assess the possibility of abortion"  The manuscript was submitted on 3 June 2017. If enrolment had taken place only in the period described earlier, it would not have been feasible to submit the manuscript just 3 months after enrolment of the last participant