How does time-lapse imaging compare with conventional embryo assessment?

[Verified against the Vienna Consensus 2017] The consensus position is direct: despite the increasing number of IVF cycles incorporating time-lapse imaging for embryo assessment and selection, the panel considered it premature to propose time-lapse related performance indicators for the IVF laboratory, owing to the limited and varied data associating precise timings of human embryo development with viability or good laboratory practice. That is a considered decision not to endorse morphokinetic parameters as quality indicators, not an omission. Two things follow for practice: There are no consensus benchmark values for morphokinetic parameters. Any thresholds in use are centre-specific or vendor-derived and should be presented as such rather than as standards. Time-lapse has two distinguishable functions that should not be conflated. Undisturbed culture — keeping embryos in a stable environment rather than removing them for assessment — is a plausible benefit independent of the imaging. Algorithmic embryo selection based on morphokinetic timings is the contested part, and is what the consensus declined to endorse. When counselling patients or evaluating a purchase, separate those. A unit may reasonably value uninterrupted culture and continuous observation while remaining agnostic about selection algorithms. Note that time-lapse is commonly offered as a paid add-on. Where it is, patients should be told which of the two functions is being claimed and what evidence supports it. Reviewer: this answer deliberately quotes no morphokinetic timings and no comparative live birth figures. Migration 045 removed an invented "ESHRE 2024" citation from this answer. If effect estimates are wanted, cite specific trials.