An embryo starts as a single cell (the egg fertilised by the 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, and it is also true that just because an embryo looks good, doesn’t mean that it is good.
With Eeva (‘Early Embryo Viability Assessment’) the embryos never leave the controlled environment of the incubator. Instead, a computer uses time-lapse image analysis of every embryo to non-invasively and safely analyse embryo development – 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 more confidently select the best quality embryo(s) for transfer.
Eeva was developed by scientists in Stanford University, California and GCRM was only the second unit in Western Europe to have the Eeva system installed, resulting in GCRM having the world’s first Eeva-conceived baby –another example of how GCRM continues at the forefront of IVF development. Find out more about Eeva.
The cost of IVF or ICSI treatment at the GCRM is fully inclusive of all costs associated with blastocyst culture and transfer. For patients who do not enter our Eeva programme, it remains GCRM’s primary culture method. 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 us to identify the best embryos.
Why isn’t it used for everyone?
At GCRM, 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’s no advantage in leaving the embryos outside the uterus. It must be emphasised that this policy doesn’t compromise the success rate of patients who don’t proceed to the blastocyst stage.
The success of IVF depends on many events, and implantation is one of the final hurdles. For successful implantation, the embryo must escape or “hatch” out of its outer shell (the zona pellucida). Once the embryo has hatched, it can make physical contact with the lining of the womb (the endometrium) and implantation can begin. If the embryo is unable to hatch from its zona pellucida, it won’t be able to implant successfully in the wall of the uterus.
Assisted hatching is a physical or chemical treatment carried out immediately before embryo transfer. It weakens an area of the zona pellucida with the aim of improving the chances of implantation. At GCRM we use a laser, as it is considered to be the safest and most accurate method.
We’d recommend assisted hatching in patients who meet one or more of the following criteria. We’ll also consider requests from patients who don’t, on a case-by-case basis:
- Repeated implantation failure (at least two previous transfers)
- Women who are 37 years and older
- Patients undergoing frozen embryo transfer
- Embryos with a thickened zona pellucida
You can read more in our Assisted Hatching patient information leaflet.
It is shown in recent studies that an ‘endometrial scratch’ may improve implantation rates in patients who have had multiple failed IVF cycles, despite good quality embryos. Embryo implantation can often fail due to poor ‘endometrial receptivity’, and an endometrial scratch may help to improve the womb lining’s receptivity to an embryo. It’s a straightforward appointment. There is an ultrasound scan, and then a procedure similar to a smear test, where a catheter is inserted into the womb through the cervix, and used to lightly mark the womb lining. It’s suitable for patients trying to conceive in a natural cycle, as well as patients going through IVF cycles.