Polanski 2015.

Study characteristics
Methods	RCT, 2 arms, 160 randomised Setting: UK, Nurture Fertility, one centre Recruitment period: January 2013 to July 2014
Participants	Criteria related to previous IVF failure: no Inclusion criteria: women younger than 49 years with history of primary or secondary infertility undergoing fresh IVF/ICSI treatment or frozen embryo replacement cycle Exclusion criteria: non‐ovulatory cycle; absent uterus; uterine instrumentation within previous 3 menstrual cycles; women in the oocyte donation programme
Interventions	Study group: endometrial biopsy procedure using Pipelle endometrial sampler (Pipelle de Cornier, Laboratoire CCD, Paris, France) or Wallace/Wallach endometrial sampler as an alternative device; ultrasound performed before the procedure. Procedure performed on cycle day luteinizing hormone (LH) +7 to LH+9 of the cycle directly preceding commencement of down‐regulation before IVF or ICSI treatment Control group: no intervention
Outcomes	Reported in paper: Clinical pregnancy, miscarriage Obtained by author correspondence: live birth, multiple pregnancy, pain (binary), bleeding
Notes	Trial registration: NCT01882842 (registered Jun 2013, registered 5 months retrospectively) Additional concerns and comments: none Funding: the University of Nottingham and Nurture Fertility through local research funds. Author correspondence: yes, undertaken with Nick.Raine‐Fenning@nurturefertility.co.uk and lucas.polanski@hotmail.com This trial was included in the previous version of this review with ongoing/interim data (Polanski 2014). The study is now finished, and was presented at a conference in 2015 but has not yet been published in full; further details and outcomes were provided by author correspondence. Publication: abstract only (and authors provided a full‐text manuscript, which has not been published).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote:"computer generated random code using random permuted blocks of randomly varying size was used to allocate participants" from author correspondence
Allocation concealment (selection bias)	Low risk	Patient details were entered into an online randomisation tool, author correspondence confirmed randomisation only revealed after entering the participants details into the computer program
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding was used
Blinding of outcome assessment (detection bias) All outcomes	High risk	The outcome of pain during the procedure and bleeding were self‐reported by participants who were not blind to their treatment allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	The authors informed us that six women in intervention arm and four in control arm excluded either because withdrew from trial or did not attend for treatment, small numbers ‐ these are only small numbers.
Selective reporting (reporting bias)	Low risk	Registered approximately 6 months into recruitment, however all important outcomes including live birth reported.
Other bias	Low risk	The paper is described as a pilot study. Despite a formal power calculation requiring 766 women the study recruited only 160 women due to available timeframe (18 months) and a recruitment rate of 50%. Additionally, the results are only available as an abstract. The authors provided a manuscript for this paper however it has not been published in full. The study was registered late by 5 months. These concerns were not deemed sufficient to constitute a high risk of other bias.