The most critical part of IVF treatment happens in a room most patients never see: the embryology laboratory. From egg retrieval to transfer day, your embryos are monitored here 24/7 in incubators that mimic the conditions of the human body.
Day 0 — Retrieval and fertilization
The retrieved eggs are evaluated under the microscope and the mature ones (MII) are identified. The same day, a single selected sperm is injected into each mature egg by ICSI. The eggs go into the incubator; temperature, humidity, pH and gas levels exactly match the body.
Day 1 — Fertilization check
In the morning, fertilization is checked: eggs showing two pronuclei (one from each parent) are now zygotes. The average fertilization rate with ICSI is above 70%.
Days 2-3 — The division race
The zygote divides into two, four, then eight cells. The embryologist grades every embryo for cell number, symmetry and fragmentation. These scores help identify the strongest candidates for transfer.
Days 4-5 — Morula and blastocyst
The cells first compact into a morula, then form the fluid-filled blastocyst. A blastocyst has the highest implantation potential — which is why most transfers today are performed on day 5. The best embryo is transferred; the remaining high-quality embryos are vitrified.
Our laboratory director Burcu Buluç and her team monitor every embryo individually, drawing on training at IVI Fertility (Spain) and McGill University (Canada); you can ask our team about your embryos at any stage.