Carter 2003.

Study characteristics
Methods	Single centre Unclear whether power calculation performed Published as abstract; study authors provided additional information
Participants	203 women from fertility clinic in USA Age < 40 years FSH < 10, ovulatory menstrual cycles, day 3 ET with good embryo quality Women with more than 1 failed IVF cycle excluded
Interventions	Laser hatching (n = 121) vs No hatching (n = 82)
Outcomes	Clinical pregnancy rate, multiple pregnancy rate
Notes	Additional information provided by study authors Dropouts 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 by computer generation on Day 3
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 dropouts
Selective reporting (reporting bias)	High risk	This was a conference abstract only and was not published as a full paper, although study authors did provide additional information. Live birth was not reported
Other bias	Unclear risk	Conference abstract