What is Pre-Implantation Genetic Screening in IVF?

Many clinics in the UK are now offering PGS, a fertility treatment which stands for Pre-Implantation Genetic Screening.  PGS is a technique used to test to see whether your embryos are chromosomally normal.

What is it? 

PGS takes place in the laboratory after your embryos are created and involves a small biopsy of your embryos around day 5 (Blastocyst stage). The biological material taken from your embryos is then screened to check which embryos are chromosomally normal (euploid).

Any embryos which are chromosomally abnormal are typically discarded. Any embryos which are chromosomally normal may be considered for transfer.

Get in Touch  to find out which of our Partner Clinics are offering PGS.

Why use PGS?

The thinking is that any embryo which is genetically abnormal (aneuploidy) will not result in a successful pregnancy after transfer – it was always destined to fail.

The idea is that PGS will help patients to select only those embryos that have a chance of succeeding; thus avoiding embryo transfers which would never have resulted in success and giving the patient a better chance of getting pregnant sooner.

Is PGS for me?  

Chromosomal abnormality is extremely common, it accounts for the majority of implantation failures and increases with age. It is therefore typically recommended as an option for patients 37 and over to consider. However, PGS is being used in younger women and consensus over which patient groups benefit most is still developing.

Mr. Stuart Lavery of our partner clinic Boston Place says that ‘what’s most important is that you give patients all the information’ and you explain that PGS won’t improve cumulative pregnancy rate but it does improve success rate by transfer.

Dr. Gillian Lockwood of Midland Fertility urges caution about the ethics of screening embryos ‘we must be very wary of where PGS is taking us ethically, where will it stop?’. Dr. Lockwood’s concerns centre on worries around genetic tampering and exclusion of certain genetic conditions that would deny society of some of its richest and most diverse personalities such as Wariwck Davies and Ellie Simmonds.

However, PGS does not detect genetic conditions (that is PGD, Pre-implantation Genetic Diagnostics, which is a topic for another time) so Dr. Lockwood’s concerns may not strictly apply to the current use of PGS.

For Mr. Lavery the evidence and the benefit to patients is what matters most and he highlights that ‘the evidence shows very significant increases in implantation rate [with PGS] of around 1/3’.

How Much does PGS cost? 

At the moment PGS does come with a high cost attached to it. You can expect to pay anything from £2,000 to £3,000.

The high cost is a result of the sophisticated technology and laboratory skill required in order to carry out the process.

Clinics are aware of the limitations of high cost and want Access Fertility to see prices reduce over time as Mr. Lavery says ‘cost is a big barrier to entry and we have to get costs down’. It is likely that costs will reduce over the next few years.

Access Fertility & PGS

You can use PGS if you are enrolled on our  Multi-Cycle Programme  for an additional fee that you pay directly to the clinic. Unfortunately, you cannot do it if you are enrolled on our  IVF Refund Programme .


It is not yet clear which patient groups will benefit most from PGS. It may also be the case that PGS is not appropriate for certain patients i.e. they are young or there are fewer than 3 blastocyst stage embryos to biopsy (PGS increases the risk to the viability of the embryo).

However, the evidence does show that the implantation rate is improved with PGS as chromosomally abnormal embryos are not transferred. For many patients knowing that they are not transferring genetically abnormal embryos will be important as it may increase time to pregnancy and spare them the heartache of a failed pregnancy test.

As Mr. Lavery says, the most important thing is that you have all the information and a conversation with your doctor will help you to understand whether PGS is something you should be considering.

Stuart Lavery

*Photo Credit The Fertilitty Partnership, Stuart Lavery. Mr Lavery is the Medical Director at Boston Pace and has done a lot of research on PGS.*

Ready to get started?

Call Access Fertility for a free no obligations chat to discuss your options.