Ge 2008.

Study characteristics
Methods	Randomised controlled trial
Participants	760 women from China having IVF with fewer than 5 failed cycles of ART with normal baseline FSH concentration. Those participants with uterine abnormality or low fertilisation capacity (rate of fertilisation < 20% and late ICSI following fertilisation failure of IVF) were excluded Mean age: fresh, 31.08 AH, 30.44 control; frozen, 31.84 AH, 30.66 control
Interventions	Laser thinning to about 50% of initial ZP thickness AH: 387 women with fresh embryos, 100 women with frozen‐thawed embryos Control: 373 women with fresh embryos, 100 women with frozen‐thawed embryos
Outcomes	Implantation rate, pregnancy rate, live birth
Notes	Unclear whether power calculation performed ITT not stated Published as full paper
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Women were randomised according to a randomisation list based on sequential numbers in sealed envelopes
Allocation concealment (selection bias)	Unclear risk	Unclear allocation
Blinding (performance bias and detection bias) All outcomes	Low risk	Blinded both clinicians and patient
Incomplete outcome data (attrition bias) All outcomes	Low risk	Fresh embryo transfer cycles: total of 831 IVF/ICSI cycles were performed during the study period. Of these, 772 met the inclusion criteria, but 12 participants abandoned embryo transfer for various reasons such as avoiding potential risks of ovarian hyperstimulation syndrome Frozen‐thawed embryo transfer: total of 245 frozen‐thawed cycles were also performed, of which 45 were excluded because they did not meet the criteria of the study or because embryo transfer was abandoned
Selective reporting (reporting bias)	Low risk	Original protocol not viewed. Live birth reported
Other bias	Low risk	None identified