Shohayeb 2012.

Study characteristics
Methods	RCT, 2 arms, 210 randomised Setting: Egypt and Saudia Arabia, academic and private settings, two centres Recruitment period: June 2009 to July 2011 (provided by the authors)
Participants	Criteria relating to previous IVF failure: yes, women with history of 2 or more failed ICSI cycles despite transfer of high‐quality embryos Inclusion criteria: normal thin endometrium (< 5 mm) on day 4 of menstruation; younger than 39 years of age Exclusion criteria: abnormal endometrial cavity (submucous myoma encroaching on the cavity, endometrial polyp, intrauterine synechia); septate or bicornuate uterus diagnosed by transvaginal ultrasound or by hysterosalpingography
Interventions	Study group: hysteroscopy and endometrial scraping were done once in the follicular phase at days 4–7 in the cycle preceding the embryo transfer cycle using a Novak curette Control group: hysteroscopy was done without endometrial scraping
Outcomes	Reported in paper: live birth, clinical pregnancy, miscarriage Obtained by author correspondence: multiple pregnancy
Notes	Trial registration: not registered (confirmed by authors) Additional concerns and comments: the second author has published 7 RCTs in the last 10 years, including 5 as first author. Trial recruitment completed July 2011 and the article was submitted for publication in December 2011 and reports on live birth; there does not appear to be sufficient time for completion of follow‐up etc within this window. Funding: no funding (confirmed by authors) Author correspondence: yes, undertaken with corresponding author (waleed_elkhyat@yahoo.com) Publication: full‐text.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Paper states quote: "The patients were randomly distributed using random number tables"
Allocation concealment (selection bias)	Low risk	Paper states quote: "the treatment allocation was done using closed sealed envelope by an assigned nurse before the hysteroscopy" and authors confirmed "envelope was numbered sequentially and was opaque brown" therefore SNOSE
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Although the description of the procedures suggest the procedure may have blinded participants to their allocation, it is not specifically stated that they were blinded and it is unclear whether participants were informed of their trial allocation
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Only objective outcomes reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	Appears to be no attrition or loss to follow‐up
Selective reporting (reporting bias)	High risk	Trial was not registered, and important outcomes such as adverse events not reported
Other bias	High risk	Trial not registered. There are concerns about the rate of RCT publication from the authors, and improbable timelines for recruitment, follow‐up and publication.