Embryo Morphokinetics Based on Time-Lapse Observation

Abstract

Embryo incubation and evaluation are critical steps in assisted reproductive technology (ART). Conventionally, embryo assessment has been done by embryologists through removing embryos from a conventional incubator during the culture period. Over recent years, time-lapse systems (TLS) have been established which can take digital images of embryos at key points and time intervals. This technique allows embryologists to assess the embryo quality in the steady culture environment. According to TLS studies and prepared algorithm models, it seems that TLS alone or in combination with conventional morphology can be considered as a useful diagnostic tool to determine high-quality embryos and improve embryonic implantation and pregnancy rates. In addition, there were remarkable diferences between embryo developmental time points and intervals regarding embryo gender, embryo fragmentation, and type of ovarian stimulation protocol. For conident conclusion, time-lapse imaging should be evaluated in further studies, and the system should be evaluated for cost/beneit ratio efectiveness in individual laboratory.Keywords: embryo cleavage, embryo morphokinetics, embryoscope, time-lapse imaging IntroductionAssisted reproductive technology (ART) may help infertile couples to realize their dream to have a child in their family, but pregnancy and live birth rates following in vitro fertilization (IVF) still remain low. It is ideal to identify viable embryos with the highest implantation potential to raise IVF success rates. In the traditional IVF practice, embryo assessments are mainly based on the morphologic observation and grade of embryologists at each stage of oocyte and embryonic development. Some features including oocyte and embryo quality, blastomere numbers and regularity, the percentage of fragmentation, and cytoplasmic granularity have been deined as prognostic indicators of successful pregnancy. This traditional embryo assessment method may have some detrimental efects on embryo growth because frequently opening and closing of incubators often cause to the change of embryo culture environmental steadiness. In order to reduce the inter-and intra-observer diference change, the time-lapse imaging (TLI) has been introduced into in vitro fertilization (IVF) laboratory. The application of time-lapse technology to the clinical IVF laboratory has supported more detailed observations on the embryo development researches quickly.The aim of this chapter is to determine whether TLI is useful for selection of "top quality" embryos for transfer to improve ART outcome rather than conventional morphological evaluation. The possible correlation between embryos' sex, embryo fragmentation, treatment protocols, diferent culture media, and embryo morphokinetics will be examined based on some new researches of TLI facilities. Furthermore, various algorithms and predictive models designed in ART cycles with TLI will be discussed.