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Pre-implantation genetic diagnosis (PGD)


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Pre-implantation genetic diagnosis (PGD) is a technique that aims to help couples who are at risk of having a child with a serious genetic condition. It creates fertilised eggs (embryos), and tests them for the familial genetic condition. 

It can help couples have a healthy child without the genetic condition. It can also help some couples who have had recurrent miscarriages due to a genetic condition.

PGD involves the Genetics Department for the genetic testing, and the Assisted Conception Unit (ACU) for the In vitro fertilisation (IVF) part of the treatment.

This information is an introduction to PGD. If you would like to find out more, speak to your genetic counsellor or clinical geneticist. They can talk to you about this more, and refer you to the PGD Service at Guy's Hospital.

How does PGD work?

  1. Referrals for each couple are sent by their local Genetics Centre. These are assessed by a member of the PGD team.
  2. If it is agreed that PGD is possible, couples will be sent an appointment with the PGD Genetics Team. This appointment is an opportunity to ask questions and for the PGD Genetics Team to agree the best type of PGD for the couple.
  3. If the couple decide to have PGD, relevant familial DNA samples and results will be collected. Family members might also need to have genetic testing.
  4. Once the results are completed, the couple will be referred to the Assisted Conception Unit (ACU). The fertility doctor will discuss the IVF process.
  5. Medicine will need to be taken to stimulate the ovaries to produce eggs. When ready, the eggs can be collected.
  6. The eggs are then fertilised with sperm in a process known as ISCI (intracytoplasmic sperm injection), and embryos are made.
  7. A sample of the embryos are taken (biopsy) to test for the genetic condition in the family.
  8. Embryos that do not have the genetic condition are suitable and can be prepared for embryo transfer with the hope of establishing a pregnancy.

This process can take 8 to 18 months. The time it takes depends on the genetic condition, and the complexities of the PGD process.

How successful is PGD?

About 1 in 3 cycles of PGD will result in a baby.

If a couple completes the process and has embryo(s) suitable for transfer, there is about a 1 in 2 (50%) chance of a pregnancy.

Funding for PGD

PGD is funded by the NHS for people living in England. This is different to IVF which is often funded regionally. 

For people living in Scotland, Wales and Northern Ireland, funding needs to be applied for. This is something that the PGD Service, as well as your Genetics Centre, can arrange.

If couples fit the criteria below, they are offered up to 3 cycles of PGD on the NHS. This funding stops if they have a healthy child, are not responding to the treatment or no longer fit the eligibility criteria.

  • Treatment must start before the women is 40.
  • Women must have a body mass index (BMI) of more than 19, and less than 30.
  • Both partners must be non-smokers.
  • Couples must not already have an unaffected child together.
  • Couples must have been in relationship for a year.
  • Couples must live at the same address.
  • Couples must have had genetic counselling locally.
  • Testing must have taken place an accredited laboratory.

For couples who are not eligible for NHS funding, self-funded treatment costs about £12,000. This costs includes the cost of the fertility medicines. Each couple will be given a specific price.

In a few circumstances, it might be possible to apply for funding if you have a health condition which stops you from fulfilling the funding criteria.

Other things to consider

PGD can be a complicated procedure, and it can take a long time. There are times of uncertainty, and many highs and lows during the process.

The timing of PGD will depend on a number of factors, including the genetic condition PGD is being used for, the availability of DNA samples from family members and funding, among other things.

Couples will likely have about 4 or 5 appointments at Guy’s Hospital for each PGD cycle. Or 4 or 5 appointments split between their local centre and Guy’s Hospital for each cycle.

There are some risks associated with PGD treatment for the woman. These can include the chance of multiple pregnancies, as well as the small chance of ovarian hyperstimulation syndrome (OHSS). These risks will be discussed in your appointments in detail before you decide to have PGD.

How to get referred

Ask your geneticist or genetic counsellor to refer you to the PGD Service at Guy's Hospital, or your local centre.

The first appointment will be with the PGD Genetics team to talk about the process in detail.



Resource number: 4857/VER1

Last reviewed: November 2019 | Next review: November 2022

A list of sources is available on request.

Where next?

 Contact us

If you have any questions or concerns about PGD, speak to your team or contact the PGD Team at Guy's Hopsital

Location: PGD Team, Clinical Genetics, 7th Floor, Borough Wing, Guy's Hospital, London SE1 9RT

Phone: 020 7188 1364 


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