What is Preimplantation Genetic Screening in IVF?

8th June 2018 in IVF

This information was correct at the time of publishing. It may not reflect our current practices, prices or regulations.

Have you experienced recurrent miscarriage or repeated implantation failure? It may have been caused by genetically abnormal embryos.

At Manchester Fertility, we can help improve your chances of a healthy pregnancy through a special test called Preimplantation Genetic Screening (PGS).

One of the most advanced IVF developments of recent years, PGS enables us to check that your embryos have the right numbers of chromosomes for a successful ongoing pregnancy, prior to transfer.

A highly specialised procedure, we’ve been performing PGS since early 2017. Here’s some FAQs all about who PGS is suitable for, how it works and the testing process:

What is Preimplantation Genetic Screening?

Preimplantation Genetic Screening is a test that allows us to examine the overall genetic health of an embryo.

Whilst our embryologists can evaluate an embryo’s quality by looking for correct cell division using high-powered microscopes or time-lapse Embryoscopes in our lab, PGS allows us to look beyond what we can see, into the embryo’s genetic make-up.

Some embryos which may appear normal may in fact be chromosomally abnormal – known as aneuploidy - and don’t have the required 46 chromosomes in each cell. As the embryo’s genetic ‘instructions’ are incorrect, it can’t form a healthy baby, and in many cases affected embryos either don’t implant or miscarry.

PGS can help avoid this by identifying which embryos are normal and abnormal in the lab at the earliest stage. PGS cannot however test for specific conditions.

Am I suitable for Preimplantation Genetic Screening for my IVF cycle?

At Manchester Fertility Preimplantation Genetic Screening can be discussed with you in detail by one of our Fertility Consultants to see whether it could help you achieve a successful pregnancy. 

Older women in particular may benefit from PGS as although patients of any age can produce a chromosomally abnormal embryo, the chances are much higher for older women. Research has shown that in patients over 40, at least three-quarters of embryos typically have aneuploidy, compared to less than half of embryos in women aged under 35.

PGS may also be offered to patients where a chromosome abnormality is a possible cause of repeated failed pregnancies or IVF cycles, despite the transfer of high quality embryos.

PGS would not usually be advised if you have a low number of embryos, as PGS can only be performed on Blastocyst Day 5 embryos and it may be better for your embryos to be transferred earlier.

How is Preimplantation Genetic Screening performed?

PGS tests the cells from the embryo that form the placenta. Only embryos that have reached Blastocyst stage will have these cells.

We’ll first need to check your embryos have high-quality cells and are suitable for biopsy. Several cells will then be carefully taken from each embryo by our team and transferred to a special genetics laboratory for testing. Your embryos are cryopreserved whilst we wait for the results of the test, around two weeks later.

PGS is a very delicate and intricate procedure using state of the art technology, and Manchester Fertility embryologists have had intensive embryo biopsy training to safely perform PGS.

Can PGS be performed on embryos that are already frozen and stored?

If you have embryos suitable for PGS in storage with us, we can thaw these to perform testing if advised. Your embryos will need to be re-frozen afterwards, which we can do successfully and at minimal risk to your embryos.

What happens once we get my Preimplantation Genetic Screening results?

Our embryologists and Fertility Consultants will use the results to determine which of your embryos are suitable for transfer.

As the embryos that have had PGS are frozen, you’ll undergo a Frozen Embryo Transfer, which involves optimising and preparing your uterus for pregnancy and precisely timing your embryo transfer. Only one embryo will be thawed and transferred to reduce your risk of multiple pregnancy.

Find out more about Preimplantation Genetic Screening and IVF

If you have any questions about PGS, talk to our Patient Advisors on 0161 300 2737. If you’d like to have IVF with us, you can start your treatment straight away. We don’t need a GP referral and you don’t need to live locally to us. Self-refer here or book in for a free one-to-one and we’ll be in touch.

Last updated: 7th June 2018