Cultivation and evaluation of embryos

Embryo culture under laboratory conditions is a demanding and closely controlled process of development from the moment of in vitro fertilization of the egg. The fundamental aim is to ensure that the conditions for embryo development are as close as possible to those in the mother’s body. For this purpose, embryologists use special culture media whose composition minimises stress and ensures all the metabolic requirements of the embryo. Stable culture conditions, i.e. constant temperature, pH and osmolarity, are necessary for optimal development.

Culturing takes place after egg collection, after fertilisation, but embryos are also cultured after cryopreservation.

The process of assessing embryos is concerned with their morphological appearance. It consists in a visual inspection of the development of the embryos. It is carried out by an experienced embryologist according to a number of criteria, such as the number of cells, size, shape and symmetry, quality of the cytoplasm, thickness of the zona pellucida, etc. The best quality embryos are then selected for transfer to the uterus.

Embryo evaluation

The evaluation process itself starts from the second day after fertilisation of the oocytes and lasts until transfer. During this period, the embryologist assesses the developmental potential of individual embryos by monitoring selected parameters. Prolonged culture lasts until day 5 of development and the embryologist has the embryo under observation for longer. The morphology of such an embryo is more indicative of its ability to nest.

In our IVF centre we use computer-controlled systems for embryo monitoring- embryoscopy. They allow real-time monitoring of the dynamics of their development without disturbing the ideal conditions of cultivation directly in the closed incubator. This sophisticated method poses no risk to the embryos. High-quality imaging makes it possible to detect embryo division defects and thus to select embryos on the basis of their morphokinetic characteristics.

Each embryo is cultured individually in a special container placed in an incubator. A camera records the progress of the whole process every 20 minutes. These recordings can be played back rapidly to obtain information on the development of each embryo at a given time.

Based on the acquired images, the embryologist can evaluate the time sequence of cell division, shape, size, fragmentation and thus determine the embryo’s developmental potential. The non-invasive measurement of the regularity of cell division of embryos in the first days of development can be used as an objective indicator of viability and can be used to select the best quality embryo for transfer to the uterus and thus increase the success rate of treatment.