While there are many factors that contribute towards a healthy birth through IVF, identifying viable embryos is one of the most important.
There are two options available at Bourn Hall that can assist with identifying viable embryos; continuous embryo monitoring in Geri and the Eeva test.
To give each embryo a strong chance of development, Geri is designed to provide an undisturbed incubation environment with high control and safety standards.
Each chamber is designed to hold a single patient’s embryos with one dedicated microscope containing a high-resolution camera per chamber. This allows for time-lapse embryo monitoring and an undisturbed incubation environment. Time-lapse embryo imaging is a non-invasive embryo monitoring technique used to acquire images of embryos automatically from inside the incubator. This allows for the visualisation of the developmental patterns during the incubation period, some of which cannot be seen using traditional incubation methods. Time-lapse embryo monitoring can aid the IVF expert when assessing your developing embryos.
The Eeva test is a non-invasive technology for assessing embryo development. It is a scientifically and clinically proven test to help identify viable embryos at an early stage (Day 3) without disrupting them (non-invasive).
An incubator with patient-specific embryo culturing chambers with a camera continuously records and monitors embryo development over time. Images recorded during embryo development are automatically analysed and the unique, predictive software identifies embryo development potential. The images required are gathered from the Geri incubation system.
The early interaction between the embryo and the lining of the uterus is a complex process. You may elect to have intravenously-administered intralipid, which although scientifically unproven, may enhance the likelihood of success.
Intralipid has been used with IVF treatment to help women who suffer either from recurrent miscarriage or repeated failed implantation following embryo transfer.
Intralipid is a 20% fat emulsion that is administered by the intravenous route. The main constituents are soya oil and egg yolk, with trace amounts of peanut oil. If you are allergic to any of these ingredients, then you should not use intralipid.
There is yet to be consensus in the medical community about if or why intralipid works. One theory that has been advanced is that as an embryo contains only half the genetic material of the mother, her uterus may see it as an invader, like a germ or foreign body.
Normally, the lining of the uterus contains immune cells that are specially adapted to tolerate an embryo. However, when these ‘friendly’ cells are not present or effective, the mother’s immune system may attack or reject the embryo with so-called ‘natural killer’ (NK) cells. This would make it difficult or impossible for the embryo to implant in the lining of the uterus.
It is thought that intralipid is able to change the immune cells in the uterine lining, making the environments more receptive to the embryo. Unfortunately, there are currently no reliable tests that can completely confirm whether a woman’s immune system will reject any embryo that tries to implant in her uterus.
Currently, there is limited evidence about the efficacy of intralipid in IVF. However, there have been encouraging reports in the UK and elsewhere. This brings the success rate of these women – with a history of several failed treatments – in line with the average rate seen in the general IVF population.
Intralipid is administered at Bourn Hall by intravenous drip infusion over a period of one to two hours. Infusions are required every three to four weeks, for a total of four or five infusions.
The first infusion is administered a few days before the embryo transfer, the second after a positive pregnancy test, the third after a viable pregnancy has been confirmed by ultrasound scan at six or seven weeks of gestation; the last infusion is given four or five weeks later.
After that the embryo should be established enough to develop without further intralipid support.
Although there is a lack of scientific evidence to prove that this technique makes a significant difference to treatment outcomes, many clinicians have observed improved implantation rates.
Endometrial scratching is a relatively simple procedure that makes a small scratch in the lining of the uterus – the endometrium– using a fine catheter, to improve the implantation rate when embryos are transferred into the uterus.
The scratch aims to induce a reaction within the uterus that makes the endometrium in the following menstrual cycle more receptive to embryos.
We normally advise endometrial scratching if you have had two or more unsuccessful treatments, despite transferring good quality embryos – whether fresh or frozen/thawed.
Reports from Bourn Hall, and from several other UK clinics, suggest this procedure is safe and that it improves implantation and IVF success rates. Constant research is taking place.
We advise that endometrial scratching is undertaken in the second half of the menstrual cycle, just before starting IVF or FET treatment.
Before an embryo can begin the process of implantation it must shed the protective shell it has grown in for the last five or so days. Making a slit in the shell assists the embryo to hatch by reducing the resistance to mechanical pressure from the embryo.
Embryos are surrounded by a protective outer coating called the zona pellucida. The thickness of this varies between patients, and it may toughen after culture in vitro, and with increased female age.
Before an embryo can implant and pregnancy occur, it must hatch from this outer coating. Hatching occurs naturally when the embryos are in the uterus. If the zona pellucida has become excessively thick or tough, hatching may be impaired or may not occur at all. When implantation fails with good quality embryos, this can be a possible cause.
Assisted hatching is a technique that involves making a small opening in the zona pellucida to enable the embryo to escape or ‘hatch’. The degree to which this improves the chances of pregnancy is difficult to measure, as reasons for using hatching are not identical in each case.
Published evidence suggests that assisted hatching may be clinically useful for patients with a poor prognosis, including those with three or more failed cycles, poor embryo quality and for older patients.
You will undertake the same treatment as for an IVF cycle with the hatching carried out shortly before embryo transfer. The use of a specially designed laser enables the embryologist to make a permanent hole of a precise size. The embryo is held in position under the microscope and the laser fired at the zona pellucida in several short bursts.
Sometimes your eggs may need a little help to complete the process of fertilisation.
In order for successful fertilisation, your sperm must release a specific functioning enzyme called Phospholipase C zeta (PLCζ) when it enters the egg. This induces waves of calcium oscillations across the egg to ‘activate it’, allowing fertilisation to occur.
A deficient or abnormal PLCζ may be the cause of failed or low fertilisation. This can be overcome in some situations using a calcium ionophore solution to activate the egg artificially.
AOA may help you if:
- Fewer than 30% of your eggs have fertilised, even after ICSI
- You have severe male factor infertility
Following a cycle of IVF with ICSI, we will use a calcium ionophore solution to stimulate the calcium release.
Your eggs will be checked for fertilisation the following day and, if the embryos continue to develop to an appropriate stage, the embryo transfer procedure will follow two to five days after the egg collection.
Pre-implantation genetic screening (PGS) is a screening test that is used to determine the chromosomal status of an embryo by screening all 23 chromosome pairs prior to transfer in an IVF cycle.
A healthy human has 23 pairs of chromosomes (46 in total) which in total make up the human genome. It has been shown that any alteration in the number of chromosomes through gains or losses, is the leading cause of failure to implant (failure to get pregnant) and miscarriage. Each person inherits one half of the pair through their mother (via the egg) and one half from the father (via the sperm) which come together after fertilisation. Five days after fertilisation, the embryo has differentiated into 2 distinct parts, the inner cell mass which will go on to form the baby, and the trophectoderm which will form the placenta.
Approximately 5 cells of the trophectoderm (placenta) are carefully removed and analysed to assess the chromosomal number of the embryo. This ensures only those embryos shown to be carrying the normal compliment of 23 pairs of chromosomes are chosen for transfer.
All couples produce a mixture of chromosomally normal embryos (euploid) and embryos where there is an additional or lost copy of a chromosome (anueploid) however the frequency of aneuploid embryos increases greatly with age. On average, a women of 35 will have equal numbers of both, by the time of 38, 70% are aneuploid. Any chromosome can be affected and it is impossible to tell simply be looking at an embryo whether it carries an aneuploidy or not. You might consider PGS for any of these reasons;
- Recurrent miscarriage – natural or IVF-cycle miscarriage.
- Repeated implantation failure.
- Advanced maternal age –
- Couples Interested in –giving themselves the highest chance of success from a single embryo transfer
An initial consultation with one of our fertility specialists will take place to agree your personalised treatment plan PGS requires a hormonal stimulation cycle followed by fertilisation with either IVF or ICSI. Thereafter embryos need to reach the blastocysts stage to undergo the test. Any normal embryos are frozen for thawing and transfer in a subsequent cycle.
Our fertility specialists will offer advice on cycle management to ensure optimal times for embryo biopsy and embryo transfer. You’ll be able to take a pregnancy test two weeks after embryo transfer. If this is positive, you’ll have a pregnancy scan at Bourn Hall about 35 days after the initial procedure.