Isik 2000.

Study characteristics
Methods	Single‐centre randomised trial
Participants	46 women from Turkey with > 5 Day 3 cleavage stage embryos (FSH at Day 3: control 6.1 (3.0); AH 5.5 (1.4) IU/L) undergoing ICSI Mean duration of infertility: 6.7 years Mean age: control group 29.1 (3.6); AH group 30.5 (5.2) years
Interventions	AH enzymatic (chemical; complete and total zona breach; 120 to 144 hour egg retrieval to AH; 0.5 to 1 hour AH to transfer) vs no AH AH: 24 women randomised, 71 embryos transferred Control: 22 women randomised, 63 embryos transferred
Outcomes	Implantation
Notes	Study author response No. of embryos transferred, blastocyst transfer: AH 2.95 (0.9); control 2.86 (0.8) 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)	Low risk	Random number table used on Day 3
Allocation concealment (selection bias)	Unclear risk	Allocation unclear
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	Not stated
Selective reporting (reporting bias)	Unclear risk	Protocol not viewed; however live birth not reported
Other bias	Low risk	None identified