Stein 1995.

Study characteristics
Methods	Single‐centre randomised trial
Participants	154 women from Israel with repeated implantation failure (> 3 attempts) undergoing IVF Mean age not stated
Interventions	AH (mechanical; complete zona breach; ? hour egg retrieval to AH; 1.5 hour AH to transfer) vs no AH AH: 72 women randomised, 230 embryos transferred Control: 82 women randomised, 295 embryos transferred
Outcomes	Clinical pregnancy, miscarriage
Notes	Attempted to contact author about this study; no reply received Unclear whether power calculation performed ITT analysis unclear Published as full paper
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation stated but method unclear or incorrect
Allocation concealment (selection bias)	Unclear risk	Unclear; no details
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Participants not blinded or unclear Assessor not blinded or unclear
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	ITT analysis unclear
Selective reporting (reporting bias)	High risk	Original protocol not viewed but study authors did not report on live birth
Other bias	Low risk	None identified