PREIMPLANTATION
GENETIC SCREENING (PGS)

The selection of ‘normal or Euploid’ embryo(s)
following genetic testing before a transfer procedure

INTRODUCTION

Preimplantation Genetic Screening PGS (also known as aneuploidy screening), is a very early method of screening that involves checking the chromosomes of embryos created using in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) for any abnormalities. Typically over 50% of embryos produced by a woman will be chromosomally abnormal and incapable of achieving a pregnancy or a healthy livebirth. PGS enables the selection of the ‘normal or Euploid’ embryo(s) for transfer giving the woman a much higher chance of achieving a pregnancy and livebirth. With age the probability of having a ‘euploid’ embryo for transfer decreases.

Next Generation Sequencing (NGS) can be used in PGS screening as it is one of the most technologically advanced means of genetic testing. It will enable us to test all 24 chromosomes simultaneously to detect any disease or abnormalities, to ensure that only the best quality embryos are returned to the uterus to develop as in a normal pregnancy.

PGS ( PGT-A) An overview

What is and isn’t tested with PGS ( PGT-A)

Why?

Older women are more likely to have eggs with abnormal chromosomes, so this screening is typically offered to women over 38 years of age. Similarly women who have faced repeated miscarriages or implantation failure may use this test to aid the transfer of a chromosomally normal embryo giving a higher chance of a healthy livebirth.

Benefits of PGS

Higher chance of pregnancy
Reduced risk of miscarriage
Minimising the risk of multiple pregnancy by selecting a single embryo for transfer
Potentially shortening the time taken to achieve a pregnancy and the costs of extra cycles.

How?

For us to carry out PGS you will have to go through routine in vitro fertilisation (IVF) procedures so that we can generate several viable eggs for collection.

The eggs will have to be microinjected to fertilise them in a procedure known as Intra Cytoplasmic Sperm Injection (ICSI). ICSI is required in PGS to limit the contamination of sperm around the resulting embryos which can potentially lead to a misdiagnosis.

During PGS, only the embryos which have developed to Blastocyst stage in the laboratory (at 5-6 days of development) are screened; whereby a small number of cells is removed from the embryo during a biopsy by one of our skilled embryologists. Your biopsied embryos will then be frozen in our onsite laboratory using vitrification whilst we await the results from the specialist genetics laboratory.

Only embryos without any chromosomal abnormalities will be placed back in the womb via a procedure called Frozen Embryo Transfer.

TREATMENT

Only one or two PGS embryos will be transferred in the same cycle to reduce the risk of multiple birth. The rest will remain frozen and preserved by us for you to use in future treatment cycles.

Disclamer HFEA

The above procedure is considered to be a treatment add-on by the HFEA. To read more on treatment add on please click here.

WHAT ARE THE SIDE-EFFECTS/RISKS?

This risks are similar to those outcomes of a traditional IVF cycle, including multiple births, ectopic pregnancies and miscarriage. Additionally, there may be situations whereby all the embryos biopsied may be chromosomally abnormal. It is also important to bear in mind that not all biopsied embryos will generate a result from the screening test. Typically 90% of biopsied embryos give a result. Embryos will be classified into three categories post screening: Euploid, Aneuploid and Mosaic. Your consultant will discuss any risks that may be relevant to your individual history and circumstances and can answer any questions you may have.

If at any time you are concerned, please do contact the clinic for advice.

Treatments

Find out more about our related services

Why Choose Us?

Here are some facts about your fertility journey with us that we’d like to share with you:

Every evaluation and treatment plan is uniquely tailored to meet your individual needs

You will have access to leading professionals, with over 35 years combined expertise, providing you with confidence and reassurance in your fertility diagnosis and subsequent treatment

Our multidisciplinary team includes specialists in fertility, urology, nutrition, counselling, genetics, endocrinology, haematology and weight management to provide a comprehensive range of support as and when you need it

We will work with you closely to understand your individual circumstances, identify any problems and agree with you, the best course of action to help make your dream a reality

We will always be honest and open about your chances of success with treatment.

Your comfort and care is always our top priority

Our focus remains entirely on you as an individual, your unique needs and your wellbeing

All investigations and treatments are provided within our new state-of-the-art clinic based in Elstree which offers a spacious environment with comfortable surroundings, to enhance your care and experience. We offer investigations and scans at our satellite locations too.

Our friendly consultant-led team is here to support you at every step throughout your fertility journey