Read our latest advice on Coronavirus (COVID-19)

Our services are open and safe to attend – we are here to help

Frequently asked questions


Coronavirus update and advice: pre-implantation genetic diagnosis update

In response to the coronavirus (COVID-19) outbreak, please read our advice and information before attending the service.


We appreciate that PGD can be a complicated process, and that you may have many questions before, during, or after your treatment. This page has some answers to frequently asked questions that we receive from couples.

Visit our PGD homepage for more general information, view our success rates or learn what to expect from your appointments.

How many appointments will I need?

In general, most couples have between five and six appointments at Guy’s Hospital. If you are travelling from a significant distance for your treatment, we can try to arrange some fertility assessments locally. We can discuss this with you at your first appointment with us.

We also offer satellite services in Exeter, Sheffield, and Leeds. More information about them can be found on our contact details page.

Who should come to the appointments?

We encourage both people in the couple to attend these appointments. If you are undergoing PGD as a single person, you are very welcome to bring a support person along. There is usually no need for family members to attend these appointments unless you wish them to.

Will I need to stay overnight?

On the day of your egg and sperm collection, we suggest that you do not travel by public transport on the way home. Some couples choose to stay overnight in London following this appointment, particularly if they live a significant distance away.

 How long does the process take?

Once you start a PGD treatment cycle, the process will take about nine weeks to reach embryo biopsy. Please see our what to expect page for further details. The most time-consuming part is the preparation before starting a PGD cycle. As we need to do laboratory testing, sometimes apply for a licence or funding and make sure that we have prepared you physically for PGD, it can take between six-12 months before starting treatment. Please see the timeline for details.

Can I have PGD if I have had in vitro fertilisation (IVF) in the past? Will this affect my NHS funding?

Unlike in vitro fertilisation (IVF), PGD is funded nationally. Having previous IVF will not usually affect your eligibility for NHS-funded PGD. However, in some circumstances, it can affect the number of PGD cycles that you may be eligible for. This will be discussed with you on a case-by-case basis.

We may also not offer you further cycles of PGD if there is an indication that it would be unlikely to be successful for fertility-related reasons. This will be discussed with you in detail following your appointment with the Assisted Conception Unit. 

How do couples cope with PGD? Is there anyone I can talk to if I'm struggling?

We appreciate that any fertility treatment can be a difficult time for patients, couples, and families. Our experienced team of PGD clinicians will be supporting you throughout the process as much as possible.

We also have a team of fertility counsellors who can provide additional face-to-face or telephone support for individuals or couples. This is included for free with your NHS treatment.

You may also wish to read some our patient stories, where families share how PGD affected them.

Should I stop taking the contraceptive pill prior to my appointments?

No. There is no need to stop taking the contraceptive pill or other form of contraception before you meet with us. The team in the Assisted Conception Unit will tell you when you should stop taking hormonal contraception prior to your treatment starting.

We strongly advise couples to continue to use a reliable form of barrier contraception (for example condoms) during the PGD process.

Should we avoid travelling to a Zika area during treatment?

Yes. We follow guidance given by the World Health Organisation (WHO) which relates to the Zika virus. Anyone travelling to a Zika-affected area should not provide a sperm sample for fertility treatment for at least three months following their return. Women should not conceive within two months of returning. You can find more information about individual countries from Public Health England.

We are happy to meet with you to create a plan for your PGD, but we would not be able to move to the next stage of treatment until this time has passed.

Do you test for anything else when you test the embryos?

No. We only test your embryos for the genetic condition(s) which is/are present in your family. We would encourage couples to consider routine investigations during a pregnancy, as we would for any couple who conceived naturally.

Some PGD centres advertise a process called pre-implantation genetic screening, or PGS. This involves looking at the numbers of chromosomes in each embryo, which claims to reduce the risk of miscarriage. However, the British Fertility Society has made a statement indicating that there is no conclusive evidence that PGS is beneficial, and literature has suggested that it may actually reduce the chance of an on-going pregnancy. Until large studies known as randomised control trials have been completed, we will not offer PGS to couples undertaking PGD.

Do you offer PGD on embryos which have been created at another centre?

In some situations, we can genetically test previously created embryos.

However, our ability to test embryos will depend on how the embryos have been stored, the stage at which they have been stored, and where they are located. The cost of transport of the embryos would not be covered by the NHS and would have to be paid for by the couple. Testing previously created embryos or eggs may affect the number of your NHS-funded cycles, or could be funded privately. We can talk to you about this at your appointment.

Find out more about our private and self-funded fees (PDF 36Kb).

Can I have a COVID-19 vaccination before/during PGD treatment?

Yes. We follow the guidance published by the British Fertility Society, who suggest you get your coronavirus (COVID-19) vaccine as soon as you are eligible. There is no need to delay your PGD treatment following vaccination. Visit the British Fertility Society website for more information.