Increasing pregnancy rates per transfer: the Time Lapse technique

This new visualisation system is key to the monitoring of embryo development.


As biologists we are faced with a dilemma when it comes to evaluating the development of embryos obtained through assisted reproduction treatment. Viewing them through a microscope – to see the number of cells, fragmentation and other morphological indicators – allows us to classify qualitative data with the purpose of selecting the embryos with the greatest chances of implantation for the transfer.

However, this way of viewing the embryos means that we have to remove them from their controlled culture conditions: a change in temperature and humidity and exposure to concentrated atmospheric oxygen and light radiation; these are all factors which can have a negative impact on embryo development.

This is the reason why embryos are observed and evaluated only when strictly necessary. In turn, however, this means that the information we have on embryo development –information which is necessary for selection of the best embryo to transfer- is very limited.

The development of image-capturing systems integrated in incubators, known as Time Lapse monitoring systems, has changed the way we see embryos. These systems take a series of photographs at specific time intervals, usually every 5 to 15 minutes. The images are viewed like a video which allows us to observe embryo development in real time and, essentially, analyse certain morphological events that are key to embryo development. Determining how and when these key elements in embryo development occur is called morphokinetic analysis, and it allows us to develop new algorithms for embryo classification.

Thus, Time Lapse systems increase the amount of information we receive about embryo development and allow us to perform a more thorough selection of those embryos which have the greatest chances of implantation.



As it is not necessary to remove the embryos from the incubator to observe them, all of this is done while the embryos remain in stable culture conditions throughout the entire process. The combination of these two elements is what allows for improved pregnancy rates per transfer when using this technology.


Miguel Gallardo
Biologist-embryologist at Ginemed Lisbon Assisted Reproduction Laboratory
Posted in Assisted Reproduction, Fertility
One comment on “Increasing pregnancy rates per transfer: the Time Lapse technique
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