Lanzendorf 1998.

Study characteristics
Methods	Single‐centre randomised trial
Participants	94 women from North America 36 years of age or older (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 previously treated with IVF Mean age: control 38.5 (0.26); AH 38.3 (0.31)
Interventions	AH by acid Tyrode's (chemical; complete zona breach; 55 hour egg retrieval to AH; ? hour AH to transfer) vs 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 whether 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)	Unclear risk	Allocation concealment via 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. Study authors did report on live birth
Other bias	Low risk	None identified