Wirleitner 2015b.

Methods	Design: 2‐arm parallel RCT
Participants	Number: 480 Women's age (mean years; experimental vs control): 40.3 vs 40.4 Inclusion criteria: women aged 38 to 43 years Exclusion criteria: recurrent implantation failure Ovarian controlled hyperstimulation: GnRH agonist long protocol Fertilisation: IMSI Stage of the embryo at transfer: blastocyst Embryo processing: fresh Number of embryos transferred: 1 or 2
Interventions	Experimental (n = 255): intrauterine hCG 500 IU dissolved in 40 μL embryo culture medium administered 3 minutes before ET Control (n = 225): administration of 40 μL culture medium without hCG 3 minutes before ET
Outcomes	Clinical pregnancy, miscarriage, live birth
Notes	Location: IVF‐Centers Prof. Zech, Bregenz, Austria Period: not mentioned Power calculation: yes Funding: funded by hospital/clinic(s) ‐ this study was not externally funded Trial registration: CRT 355 Publication type: abstract
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation was mentioned without further details.
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants were blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not blinded, but unlikely to induce bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants were followed up.
Selective reporting (reporting bias)	Low risk	Reports on all relevant outcomes
Other bias	Low risk	Baseline characteristics of participants were comparable between 2 study groups.