Embryoscope
Today, it is possible to monitor embryos continuously for 24 hours. Thanks to this advancement, cell division and developmental stages that were previously missed can now be observed without interruption. Especially in cases where single embryo transfer is mandatory, embryo selection becomes much more important, making it possible to offer patients the highest possible chance of success.
Embryos Under 24-Hour Continuous Monitoring
As is well known, under current conditions in clinical embryology laboratories, the selection of the highest-quality embryo for transfer is performed by examining certain morphological characteristics of the embryo under a microscope. These morphological evaluations are carried out at specific intervals in accordance with the embryo’s cleavage stages. During this process, embryos are assessed to determine whether they meet the required developmental criteria. Therefore, when embryo development is evaluated using classical morphological methods, the observation is essentially static.
However, embryo development is not a static event; it is a highly complex and dynamic chain of processes. Some indicators that may reflect embryo viability cannot be observed through static evaluation. For this reason, although classical morphological assessment can guide the selection of embryos with high viability, its predictive value remains limited.
Based on this concept, several medical technology companies, with the support of researchers, have developed camera monitoring systems that can be integrated modularly into incubators or built directly into them. These systems allow embryo development to be examined in detail through continuous observations taken at least every five minutes over a 24-hour period. With these monitoring systems, it has become possible to evaluate embryo development dynamically.
This approach aims to identify certain characteristics that may be important indicators of embryo viability but cannot be detected by static methods, thereby enabling the selection of embryos with the highest developmental potential using a method with greater predictive value. For this purpose, several scientific studies—particularly from European countries—have been published since the late 2000s.
In these studies, cleavage stages observed during embryo development were evaluated individually (for example, the first cleavage stage: division of the fertilized egg into a two-cell stage; the second cleavage stage: division of the two-cell embryo into three to four cells). The time required for embryos to complete these cleavage stages was compared with the viability of the transferred embryos.
In addition to cleavage timing, it has been suggested that certain specific morphological characteristics—difficult to observe clearly with static evaluation—may also serve as indicators of embryo viability. However, for embryo monitoring systems to be widely implemented in all embryology laboratories in routine practice, several issues still need to be clarified.
Although some published studies in the literature have demonstrated beneficial effects, it has not yet been scientifically proven—through well-designed, prospective, comparative studies—that embryo monitoring systems provide a significant advantage over classical embryo evaluation methods in terms of ongoing pregnancy and live birth rates.
Another scientific issue that requires clarification regarding monitoring systems is the extent to which embryo cleavage stages are affected by external factors such as ovarian stimulation protocols, embryo culture conditions in the laboratory, culture media used, and temperature variations. If these factors do influence cleavage timing, it is essential to determine how they alter the ideal time intervals.
Otherwise, universal standardization of these time intervals will not be possible, and any proposed time-based scoring system may vary across laboratories using different techniques. Since the cost of embryo monitoring systems is significantly higher than that of classical morphological evaluation methods, their routine use in laboratories—and their complete replacement of traditional methods—will only be feasible once these scientific details are clearly established.