Pecorino 2018.

Study characteristics
Methods	RCT, 2 arms, 80 randomised Setting: Italy, one centre Recruitment period: unclear
Participants	Criteria related to previous IVF failure: yes, at least two previous failed ICSI or FIVET (failed implantation) Inclusion criteria: between 25‐ 37 years, primitive or secondary infertility, normal thickness and endometrial ultrasound pattern, defined as absence of intracavitary disease (fibroids, polyps, etc.), with no anamnestic severe deep endometriosis, good quality of seminal fluid of partner and negative anamnesis for relevant diseases, negative genetic, metabolic and infective evaluation. Exclusion criteria: as above
Interventions	Study group: endometrial scratching was performed by a dedicated team (2 operators only) during luteal period, between 5 and 10 days before menstruation. Pipelle used. Control group: sham procedure using an embryo‐transfer catheter introduced along the cervix inside the uterine cavity.
Outcomes	Reported in paper: clinical pregnancy, pain, bleeding Obtained by author correspondence: pain mean and SD (intervention group mean pain 5.6, SD 1.2, control group: mean 4.0, SD 0.9), multiple pregnancy (only reported in one arm in paper)
Notes	Trial registration: authors confirmed the trial was not registered Additional concerns and comments: the implantation rate does not appear to have been calculated correctly, however this does not have a bearing on the outcomes included in this review. Funding: Authors state the trial was funded "by the Hospital" Author correspondence: yes, undertaken with Basilio Pecorino eliopek@gmail.com Publication: full‐text.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The paper states quote:"performed a randomized unblinded controlled trial (RCT) in a ratio of 1:1" correspondence with the authors confirmed "computerized random numbers" were used
Allocation concealment (selection bias)	Low risk	No description in the paper however correspondence with authors confirmed each quote: "patient was inserted after login in a Crf software for randomization. Crf returned the modality of scratching for each patient: scratch or control" and that "there was no way to foresee the next allocation before randomization" which suggests adequate allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Control group underwent a sham procedure however the authors also describe the study as unblinded quote:"performed a randomized unblinded controlled trial". Authors confirmed that patients were blind to their trial allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Subjective outcome of pain reported and participants were blind to their trial allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	Paper states quote:"All of recruited patients completed reproductive procedures including embryo transfer" therefore no attrition
Selective reporting (reporting bias)	High risk	Study was not registered and important outcomes such as Live birth not reported
Other bias	High risk	Trial not registered