Carter 2003.

Methods	Single centre Unclear if power calculation performed Published as abstract and authors provided additional information
Participants	203 women from fertility clinic in US Age < 40 years FSH < 10, ovulatory menstrual cycles, day 3 ET with good embryo quality Women with more than one failed IVF cycle were excluded
Interventions	Laser hatching (n=121) versus No hatching (n=82)
Outcomes	Clinical pregnancy rate, multiple pregnancy rate
Notes	Additional information provided by authors Drop‐outs were included for the denominator in this review No. of embryos AH 2.2; Control 2.1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised, method by computer generation on day three
Allocation concealment (selection bias)	Unclear risk	Unclear, no details provided
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 but included drop‐outs
Selective reporting (reporting bias)	High risk	This was a conference abstract only and was not published as a full paper although the authors did provide some additional information. Live birth was not reported