Narvekar 2010.

Study characteristics
Methods	RCT, 2 arms, 100 randomised Setting: India, private fertility clinic, one centre Recruitment period: May 2007 to July 2008
Participants	Criteria relating to previous IVF failure: yes, women with at least 1 previous failure Inclusion criteria: good responders in the previous IVF cycle (development of at least 4 good‐quality embryos); ≤ 37 years Exclusion criteria: endometrial tuberculosis in the past; intramural fibroid distorting the endometrial cavity/submucous myoma; Asherman's syndrome; evidence of hydrosalpinx
Interventions	Study group: pipelle procedure conducted twice: once at the time of hysteroscopy on days 7‐10, and again on days 24‐25 (of the cycle before IVF) Control group: hysteroscopy on days 7‐10 of the cycle before IVF
Outcomes	Reported in paper: live birth, clinical pregnancy, miscarriage, multiple pregnancy Obtained from author correspondence: ‐
Notes	Trial registration: trial does not appear to be registered Additional concerns and comments: none Funding: none stated Author correspondence: yes, undertaken with corresponding author (sachnar@rediff.com) Publication: full‐text. Numbers of previous attempts were 2.3 ± 0.52 and 2.5 ± 0.7, so the study was classified in the subgroup 'Two or more previous failures'
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random numbers were used
Allocation concealment (selection bias)	Low risk	Sealed and consecutively numbered opaque envelopes were used
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	It does not appear there was any attrition or loss to follow‐up
Selective reporting (reporting bias)	High risk	The trial does not appear to have been registered, and important outcomes such as adverse events not reported
Other bias	High risk	Trial not registered.