Embryological Techniques/Advances

Early Embryo Viability Assessment (Eeva)

An embryo starts as a single cell (the egg having been fertilized by a sperm). This cell divides into 2 cells, these 2 cells divide into 3 and then 4 cells, and so on. The specific timing of when the cells divide is crucial to the ultimate quality of the embryo. At present embryologists take the embryos out of the incubator each morning, look at them to see if they have reached certain milestones in their development and grade the embryos based on what they look like. However, the embryologist cannot know at what time the cells actually divided. So although it may have a perfectly healthy appearance, it may not have divided at the appropriate time interval.

With Eeva ('Early Embryo Viability Assessment') the embryos never leave the controlled environment of the incubator, and a computer uses time-lapse image analysis, of every embryo, to non-invasively and safely analyse embryo development and in particular the timings of the cell divisions.

Through the use of Eeva, we aim to improve IVF outcomes by providing embryologists and patients with objective information about each embryo, enabling them to select more confidently the embryo(s) for transfer.

Eeva was developed by scientists in Stanford University, California. GCRM-BELFAST is the first clinic in Northern Ireland to use the Eeva system – another example of how GCRM-BELFAST continues at the forefront of IVF development (for more information, see Treatments and Pricing / Eeva).

Blastocyst culture

The cost of IVF or ICSI treatment at GCRM-BELFAST includes all costs associated with blastocyst culture and transfer. For patients who do not enter our Eeva program it remains GCRM-BELFAST’s primary embryo culture method where embryo quality and number permits. A blastocyst is an embryo that has been developing for five or six days after fertilisation, during which time it grows into a ball of more than 50 cells. Recent evidence supports the use of blastocyst culture and transfer in certain patients, including those seeking single embryo transfer, as it helps identify the best embryo.

So if it is so successful why is blastocyst transfer not used for everyone?

At GCRM-BELFAST, as a guide, patients with at least 3 good quality embryos on day 3 will be considered suitable for blastocyst stage transfer. If the number of embryos is lower than 3, there will be no advantage in leaving the embryos outside the uterus. It must be emphasised that this policy does not compromise the success rate of patients who do not proceed to the blastocyst stage.


When it’s time to transfer your embryos they are incubated in a special solution called EmbryoGlue just before the transfer procedure.

EmbryoGlue acts like a glue to help your embryo stick to your uterus, containing high amounts of naturally occurring molecules and fluids that you’d find in your own body during natural pregnancy, including when an embryo implants. One of these molecules known as hyaluronan increases dramatically on the day of implantation and decreases to near normal levels by the next day, indicating that it is important for implantation of your embryos.



EmbryoGlue is used free of charge for all of our patients.and is part of our continuous programme of investment in looking at new ways to help our patients. We only ever offer proven, evidence-based products and procedures, so you can be sure that they really can help your chances of success.


For many years the standard method of freezing eggs and embryos involved the use of a slow rate freezing machine. The process took 2-3 hours to complete and involved a lot of input from the laboratory staff. In terms of results, it proved to be a successful technique. More recently a new freezing technique called ‘Vitrification’ has been developed. This is a more rapid method of freezing eggs and embryos that has been shown, over time, to offer better success rates. GCRM-BELFAST will offer Vitrification from its opening.

Assisted Hatching

The success of IVF is dependent on many events, one of the final steps being implantation. For this to occur, the embryo must escape from its outer shell (the zona pellucida) - known as "hatching". Once the embryo has hatched it can make physical contact with the lining of the womb (the endometrium) and implantation can begin. Failure of implantation may result from an inability of the embryo to hatch from its zona pellucida. Assisted hatching is a physical or chemical treatment which weakens an area of the zona pellucida with the aim of improving implantation. At GCRM-BELFAST we use a laser, as it is considered to be the safest and most accurate method. See Assisted Hatching patient information leaflet for further details. There is an additional charge for Assisted Hatching, please refer to the current price list for details.