Antinori 1999.

Methods	Randomisation stated, but method unclear or incorrect Allocation concealment unclear Unclear if single/multicentre Participants not blinded or unclear Assessor not blinded or unclear Unclear if power calculation performed ITT analysis unclear Published as abstract
Participants	341 Women from Italy undergoing IVF. Subgrouped by previous IVF experience: a) without previous IVF experience (n=199) or b) with more than 6 previous IVF failures (n=142) Mean age: control group 27.0; AH group 27.5 years
Interventions	AH (laser; complete zona breach; unclear how long from egg retrieval to AH; unclear how long from AH to transfer) ‐ 169 women randomised, 221 embryos transferred (estimated) versus Control ‐ no AH ‐172 women randomised, 247 embryos transferred (estimated)
Outcomes	Clinical pregnancy, miscarriage, multiple pregnancy
Notes	No reply No of embryos transferred: AH 2.3, Control 2.4
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation stated, but method unclear or incorrect. Day not stated
Allocation concealment (selection bias)	Unclear risk	Unclear
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Unclear. Participants not blinded or unclear. Assessor not blinded or unclear
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	ITT analysis unclear and no evidence of any losses
Selective reporting (reporting bias)	Unclear risk	This is a conference abstract. There is no evidence of a full paper, live birth was not reported