In dividual participant data meta-analysis of trials comparing f r o zen versus f r esh e m bryo transfer strategy (INFORM): a protocol.

Introduction: Existing randomised controlled trials (RCTs) comparing a freeze-all embryo transfer strategy and a fresh embryo transfer strategy have shown conflicting results. A freeze-all or a fresh transfer policy may be preferable for some couples undergoing in-vitro fertilisation (IVF), but it is unclear which couples would benefit most from each policy, how and under which protocols. Therefore, we plan a systematic review and individual participant data meta-analysis of RCTs comparing a freeze-all and a fresh transfer policy.
Methods and Analysis: We will search electronic databases (Medline, Embase, PsycINFO and CENTRAL) and trial registries (ClinicalTrials.gov and the International Clinical Trials Registry Platform) from their inception to present to identify eligible RCTs. We will also check reference lists of relevant papers. The search was performed on 23 September 2020 and will be updated. We will include RCTs comparing a freeze-all embryo transfer strategy and a fresh embryo transfer strategy in couples undergoing IVF. The primary outcome will be live birth resulting from the first embryo transfer. All outcomes listed in the core outcome set for infertility research will be reported. We will invite the lead investigators of eligible trials to join the In dividual participant data meta-analysis of trials comparing f r o zen versus f r esh e m bryo transfer strategy (INFORM) collaboration and share the deidentified individual participant data (IPD) of their trials. We will harmonise the IPD and perform a two-stage meta-analysis and examine treatment-covariate interactions for important baseline characteristics.
Ethics and Dissemination: The study ethics have been granted by the Monash University Human Research Ethics Committee (Project ID: 30391). The findings will be disseminated via presentations at international conferences and publication in peer-reviewed journals.
Prospero Registration Number: CRD42021296566.
Competing Interests: Competing interests: RW reports grants from the NHMRC and NHMRC Centre for Research Excellence in Women's Health in Reproductive Life (CRE WHiRL). LNV reports personal fees from Merck, Merck Sharpe and Dohme, Ferring, outside the submitted work. AP reports grants and personal fees from Gedeon Richter, Ferring Pharmaceuticals and Merck A/S and personal fees from IBSA, outside the submitted work. CB reports grants and personal fees from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S and Organon, and personal fees from IBSA and Abbott outside the submitted work. CS is a co-inventor of Igenomix SL and Head of Scientific Advisory Board at Igenomix SL. BWM is supported by a NHMRC Investigator grant (GNT1176437). BWM reports personal fees from ObsEva and Merck, and travel support from Merck, outside the submitted work. SB is the Editor in Chief of Human Reproduction Open. AM reports grants from HTA/NIHR, travel/meeting support from Ferring and Pharmasure and participation in a Ferring advisory board. All other authors do not have competing interests to declare.
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