Hagemann 2010.

Methods	Randomised, single centre, crossover trial
Participants	103 women in the United States under 38 years of age with any embryo with a zona pellucida thickness > 13μm and more than 2 previous failed IVF cycles Mean age: 32.1 years in the hatched group, 31.2 in the unhatched group
Interventions	AH performed by acidic Tyrode's solution AH: 49 women Control: 54 women
Outcomes	Clinical intrauterine pregnancy rate, implantation rate, spontaneous pregnancy loss and live birth rate
Notes	Power calculation: study states it has inadequate power. The study as ultimately performed only had sufficient statistical power to identify a 30% absolute effect size with alpha = 0.05 and beta = 0.80 ITT analysis unclear Published as full paper
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was performed by the IVF lab staff by drawing 1 of 200 opaque envelopes from a box
Allocation concealment (selection bias)	Unclear risk	Opaque envelopes drawn, but not numbered
Blinding (performance bias and detection bias) All outcomes	Low risk	The study arm to which participants belonged was blinded to care givers, with the exception of the IVF embryologyists, as well as to participants
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear
Selective reporting (reporting bias)	Low risk	Live birth reported (but results not included in this study as results were only given for both cycles combined and not for just the first cycle, which is the data we are using). No other evidence of reporting bias