Lanzendorf 1998.

Methods	Single centre, randomised trial
Participants	94 women from North America aged at least 36 years (mean basal FSH control 7.6 IU/L (SD 2.0); AH 7.9 IU/L (SD 2.5)), undergoing IVF (some with ICSI), half had been previously treated with IVF Mean age: control group 38.5 (0.26); AH group 38.3 (0.31)
Interventions	AH by acid tyrodes (chemical; complete zona breach; 55 hours egg retrieval to AH; ? hours AH to transfer) versus no AH AH: 42 women randomised, 180 embryos transferred Control: 52 women randomised, 212 embryos transferred
Outcomes	Implantation, clinical pregnancy, multiple pregnancy, live births
Notes	Attempted to contact author about this study. A reply including much useful additional information was received No. of embryos stated: AH 4.4; Control 4.4 Unclear if power calculation performed ITT analysis performed
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised, method stated
Allocation concealment (selection bias)	Low risk	Allocation concealment using sealed envelopes on day of aspiration
Blinding (performance bias and detection bias) All outcomes	Low risk	Participants blinded Assessor blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT analysis performed
Selective reporting (reporting bias)	Unclear risk	No evidence of selective reporting, although original protocol not viewed. Authors did report on live birth