IVF Add-ons

Our embryologists and fertility experts are here to help you, from our clinics in Cambridge, Norwich and Wickford.

Our patient-centred care means that under some circumstances supplementary treatments, known as add-ons or adjuvants, may be offered (these include things such as GERI time-lapse, intralipids, embryo screening (PGT-A), endometrial scratching and assisted hatching). These are treatments that have been found to work for some patients, however, they do not have a rigorous evidence-base to support wider use.

Read further details below and for the latest on the effectiveness and safety of add-ons or adjuvants we recommend that you visit the HFEA website where our regulator has summarised the consensus of UK medical and scientific opinion.

Our team would be pleased to provide you with more advice on when to use IVF add-ons rationally and effectively.

While there are many factors that contribute towards a successful IVF treatment, stable, optimised embryo culture conditions and identifying the strongest embryos are amongst the most important.

Designed to provide an individualised, undisturbed, optimal and stable environment, GERI gives each embryo the very best chance to develop, from fertilisation through to embryo transfer. The incorporation of one of the most advanced time-lapse camera systems allows our embryologists to observe embryo development stage by stage. Whilst embryo safety is assured as each chamber is independently controlled and checked by a class leading monitoring system.

Each chamber holds a single patient’s embryos with a dedicated microscope and a high-resolution camera that captures 7 different images of each embryo every 5 minutes. This completely non-invasive automatic system generates a video of embryo development providing detail that can never be seen with traditional incubation methods. Careful examination of the time-lapse videos by our expert embryologists enables us to select embryos with the strongest development, thereby identifying the best embryo(s) for transfer or freezing – optimising the chances of a successful pregnancy.

You will additionally receive a copy of all of GERI Time-lapse videos.

Bourn Hall is one of a limited number of centres in the UK, and the only clinic in the East of England to offer GERI.


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 and help in selecting the best embryo(s) for transfer or freezing to optimise the chances of a successful pregnancy.

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.

How does it work?

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.

Is it right for me?

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.

What next?

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.

How does it work?

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.

Is it right for me?

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.

What next?

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.

How does it work?

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.

Is it right for me?

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.

What next?

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.

EmbryoGlue is a medium specially developed for use in the laboratory at the time of your embryo transfer, which some studies have shown to improve your chances of pregnancy.

How does it work?

EmbryoGlue is a culture media, which has an increased viscosity compared to conventional embryo transfer medium and contains hyaluronan, a compound found in the uterus at the time of implantation. It has been developed to mimic the conditions in the womb and may help your embryos implant after transfer.

There is moderate evidence to suggest an improved clinical pregnancy and live birth rate with the use of EmbryoGlue in your treatment cycle.

There are no known risks from using EmbryoGlue.

Is it right for me?

If you are having an embryo transfer as part of your treatment, EmbryoGlue may help to improve your chances of success.

What next?

Following either fresh or frozen embryo treatment, your embryos will be placed in the EmbryoGlue solution prior to your embryo transfer.

Endometrium is the tissue lining the interior of the womb where the embryo implants and grows during pregnancy. The endometrium is ‘receptive’ when it is ready for embryo implantation to occur. This period of receptivity is called the window of implantation (WOI).

In some women, this window of implantation may be earlier or later. ERA test allows us to assess whether the uterus is receptive at the usual time of embryo transfer.

EndomeTRIO testing can also be undertaken at the same time as ERA

A healthy endometrium contains healthy bacteria called lactobacilli this test evaluates endometrial flora and recommends the best probiotic treatment to balance your endometrial flora to improve your pregnancy prospects the test also detects the most frequent bacteria causing chronic endometritis (inflammation of the womb lining) and we will then be able to recommend specific antibiotic for successful treatment.

How does it work?

The ERA test analyses 248 genes in an endometrial sample to evaluate endometrial receptivity and determine the optimal time for embryo transfer, which can increase the chance of pregnancy.

Is it right for me?

We normally advise ERA and endometrio testing if you have had two or more unsuccessful treatments, despite transferring good quality embryos – whether fresh or frozen/thawed.

Constant research is taking place and report the safety of this procedure and that it improves implantation and IVF success rates.

What happens next?

A consultation with one of our fertility specialists will take place to agree your personalised treatment plan, ERA requires a mock cycle with an endometrial biopsy. Embryos will be transferred in a subsequent cycle.

Our fertility specialists will offer advice on cycle management to ensure optimal times for the mock cycle and subsequent embryo transfer.