Prenatal Genetics

We hold a weekly prenatal clinic at the Northern General Hospital where we see pregnant women. We may see them because something has been picked up in the pregnancy or we may already know the family for a pre-existing genetic condition.

Occasionally it is appropriate to offer testing during pregnancy and this is called prenatal diagnosis.

Pre-implantation Genetic Testing (PGT) Service

It allows the birth of an unaffected child by testing an embryo before it is implanted in the uterus. This technique is very complex and not suitable or appropriate for everyone.

There are a large variety of genetic disorders and chromosomal disorders but pre-implantation genetic testing is only available for conditions approved by the Human Fertilisation & Embryology Authority.

We are a PGT satellite unit for Guy’s Hospital, London.

How to be referred

Please ask your GP or clinician to refer you to  the Sheffield Clinical Genomics Service, OPD2, Northern General Hospital, Herries Road, Sheffield S5 7AU

The process

PGD involves the use of Assisted Reproductive Technology (ART) to produce and fertilise eggs. If fertilisation is successful, after a few days, one or two cells are removed from the embryo and tested for the altered gene or chromosomal abnormality.  If an unaffected embryo is produced it is the transferred to the womb or uterus.

The egg collection and embryo transfer parts of the process take place in Guy’s Hospital, London, but we can organise the initial appointments and start the IVF locally.

The PGT website at Guy’s Hospital provides useful information about PGD such as what to expect at appointments, success rates, limitations and all the steps involved in the process.

A sample case

A couple have a child with cystic fibrosis. They would like to extend their family but want to avoid having a second child with this condition. Also, they do not want to consider termination of pregnancy.

The couple want to find out more about PGT so there is an initial appointment to discuss this and their other options. From 1 April 2013 criteria for funding PGT are set nationally to avoid variation depending on where you live.

If the decision is made to go ahead, then the fertility tests are arranged in collaboration with the GP and the Assisted Conception Unit (ACU) which is based at the Jessop Wing, Royal Hallamshire Hospital, Sheffield.

Blood samples are then sent to Guy’s Hospital, London where they confirm if they will be able to get a result from a single cell taken from each embryo. Once all the checks are in place the in vitro fertilisation (IVF) part of the process can be started locally in Sheffield.

Depending on the complexity and whether a pregnancy is achieved, the whole process can take between 12 and 18 months.

Clinics

Clinics are held at Northern General Hospital and at the Assisted Conception Unit (ACU) Jessop Wing, Royal Hallamshire Hospital.

Clinicians wishing to make a referral should send a referral letter to:

Richard Sayers
Principal Genetic Counsellor
OPD2 Northern General Hospital
Herries Road
Sheffield
S5 7AU