Time-Lapse Monitoring

Ovarian stimulation is an integral part of IVF cycles, often resulting in numerous retrieved oocytes and the generation of multiple embryos. In most cases out of this cohort, one to two embryos are selected for embryo transfer. Historically, embryos that are generated during an IVF treatment are ranked by assessing morphology and cleavage status under light microscopy to determine which are best for transfer. Genetic, metabolic testing of embryos and extended culture to the blastocyst stage have been recommended as tools to improve selection. Recently, time-lapse (TL) embryo culture and monitoring has been integrated as an additional tool to help choose the embryo with the highest implantation potential. Embryos cultured in TL units can be observed though a series of images taken at regular intervals without removing them from optimal culture conditions. This provides significantly more data on the kinetics and morphologic changes during early embryo development, which may be used to differentiate embryos for optimal transfer. Retrospective studies and a few randomized clinical trials have compared clinical outcome with TL-aided embryo selection compared to the current standard of daily morphologic assessment. The identification of morphokinetic markers shows promise that can be prospectively applied to rank embryos and has subsequently been incorporated into algorithms to further aid the embryologist’s optimal embryo selection. This chapter will provide an up-to-date summary of time-lapse technology and clinical findings as well as an updated meta-analysis of available data.