Karimzade 2010.

Study characteristics
Methods	RCT, 2 arms, 156 randomised Setting: Iran in an academic setting Recruitment period: June 2008 to January 2009
Participants	Criteria related to previous IVF failure: yes, participants were undergoing their first IVF cycle Inclusion criteria: age < 38 years; BMI > 19 kg/m² and < 30 kg/m²; day 3 follicle‐stimulating hormone < 12 mIU/ mL; triple‐layer endometrium with thickness > 8 mm on the day of human chorionic gonadotrophin administration; normal ovarian response to stimulation (estradiol on the day of trigger between 500 and 3000 pg/mL and between 4 and 14 retrieved oocytes Exclusion criteria: any uterine anomaly such as myoma and endometrial polyp on USTV; endometrioma with a diameter > 3 cm; visible hydrosalpinges
Interventions	Study group: one endometrial injury procedure using Novak curette on the day of oocyte retrieval Control group: no intervention
Outcomes	Reported in paper: ongoing pregnancy, clinical pregnancy. Miscarriage calculated as the difference between clinical and ongoing pregnancies. Obtained by author correspondence: ‐
Notes	Trial registration: NCT00846183 (registered Feb 2009, registered retrospectively) Additional concerns and comments: over a recruitment period of 8 months the researchers recruited 156 women (19.5 per month). This is a high recruitment rate for one centre. Three of the four authors are also authors of an RCT which has been retracted for methodological issues, which may have been misrepresented (e.g. not a true RCT) (Aflatoonian 2013). Funding: no description Author correspondence: attempted but no response received Publication: full‐text.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "computer generated randomization method"
Allocation concealment (selection bias)	Unclear risk	No description
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding was employed
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Only objective outcomes reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	Four women were excluded from the analysis because they had bleeding on the day of planned embryo transfer and therefore embryo transfer was cancelled. It is a reasonable assumption that these four women did not conceive.
Selective reporting (reporting bias)	High risk	Trial was registered retrospectively and live birth not reported
Other bias	High risk	Quote:"because of significant lower pregnancy rates in the experimental group, the study was stopped sooner" it is not clear whether adequate stopping rules were used. Trial registered retrospectively. Three authors are also co‐authors of a retracted paper.