Time-lapse in the IVF-lab: how should we assess potential benefit?

Time-lapse imaging of embryos has been widely introduced to fertility laboratories worldwide with the aim of identifying the best quality embryos to transfer that will ultimately improve IVF success rates. In this opinion paper, we explore the lack of evidence of benefit of this novel intervention, analyse the methodological flaws of current studies, offer ideal study designs that assess the various features of time-lapse imaging, and discuss forthcoming studies. In particular, we emphasize the ethical aspects of hastily adopting a costly technology without current high level evidence of improved live birth rates, safety and cost effectiveness.