Further information on the NHS Leeds Prenatal Family History can found by watching the following video. You can also watch the video translated in Arabic, Polish, Punjabi, Romanian or Urdu.
NHS Leeds Prenatal Family History
We understand that this may be a worrying time for you and your family.
You may feel quite overwhelmed with new, sometimes complex, information that you are being given.
As part of your care, your doctor or genetic counselor has offered you a prenatal invasive test because either:
You have had a baby with a genetic condition already, or
You or your baby’s father have a family history of a known genetic condition.
We will explain this test now, and more information is available from the relevant patient information leaflets and discussions with your healthcare professionals. Please take notes, and they will be more than happy to answer any questions you might have.
To understand why these genetic tests can be helpful, it is useful to first learn a little more about your baby’s genes.
Genes are instructions that tell our bodies how to grow and develop.
Genes are made of DNA and stored in our chromosomes. Chromosomes come in pairs, and we usually have 46 in total. They are numbered from 1 to 22, and the 23rd pair are called the sex chromosomes.
When one or both parents are carriers of or affected by a genetic condition, they have a chance of passing this on to their children, even if they themselves are healthy. A prenatal invasive test will tell you if the known condition has been passed on to your baby.
Deciding to have a test is a personal choice. You may wish to consider what the results may mean for your pregnancy and family. If you decide to have a test, you will be referred to your nearest fetal medicine unit. Your fetal medicine doctor may advise as to the referred test based on ultrasound findings and ease of obtaining the sample to minimize the risks.
The tests you are offered may depend upon your personal choice and how many weeks pregnant you are. Both tests will give you the same results and carry the same risks. Invasive tests are associated with a small additional chance of miscarriage; nationally, this figure is one chance in 200. This chance may be higher depending on your scan findings.
Occasionally, it’s not possible to obtain a result, in which case you’ll be offered a repeat test.
To prepare for the test
On the day, eat and drink as normal.
Wear comfortable clothing.
Bring your partner or another adult to support you, if you wish.
If you take any blood thinning medications, please discuss this with your healthcare provider prior to your appointment.
Take it easy for 24 hours after your test, and therefore consider any work or child care arrangements.
A chorionic villus sample uses a needle to obtain a small piece of tissue from the placenta (also known as the afterbirth). It can be performed as early as 11 weeks into your pregnancy. One in ten placentas are not in a position that makes the test possible. This would mean having to delay your test.
An amniocentesis uses a needle to obtain a small sample of amniotic fluid that surrounds the baby in the womb. It can be performed after 15 weeks of pregnancy. An ultrasound scan is performed throughout the test, and antiseptic solution will be applied to clean your tummy. If you have a CVS test, a local anesthetic injection is also given to numb the skin. This may briefly feel like a stinging sensation. A needle is guided through the wall of the womb into either the placenta or amniotic fluid, away from your baby. You may feel a pushing sensation and tummy cramps. Once the sample is obtained, the needle is removed, and a small plaster is applied to your tummy. These tests typically take around five to ten minutes.
After the test
You and your partner may be asked to provide a blood sample from your arm to help us understand your results.
If your blood group is rhesus negative, there is a chance of the passage of your baby’s red blood cells into your system after an invasive procedure.
An injection called anti-D immunoglobulin may be offered to you. This is to prevent antibodies from developing in case your baby has a different blood group to you.
You can go home soon after the test.
You may get some period-type cramps, which should settle with some simple analgesia, such as paracetamol.
It’s fine to bathe or shower following your procedure.
If a complication were to occur relating to the test, this would typically be within two weeks but up to six weeks later.
If you experience vaginal bleeding, watery vaginal discharge, worsening of abdominal cramps, or a high temperature, contact your local maternity unit for advice and assessment.
The timing of your specific genetic test result will be discussed with you by your doctor or genetic counselor. Typically, this is within one to two weeks.
Your results will tell you if the condition has been passed on to your baby or not.
With your agreement, you will be called with this information by one of the professionals supporting you.
You will also be offered testing for the most common chromosome conditions, thereby excluding or diagnosing Down syndrome, Edward syndrome, Patau syndrome, and some sex chromosome changes. This test is called a qf-PCR.
Deciding to test for these conditions will not cause any delay to your results.
As with all health data, the results from your genetic test will be stored securely by the NHS.
Your results will only tell you about the conditions that have been tested for and the sex of your baby, if you wish to know.
If the results show a genetic change, your doctor will discuss this with you and explain what this may mean for your baby.
You may find you need some time to process all of the information and wish to be signposted to UK websites and charities that work in this area.
If a genetic change has been detected, some parents opt to continue with their pregnancy, knowing that care for them and their baby will be tailored to individual needs.
Others, after consideration, may opt not to continue with their pregnancy, knowing that they will be supported in their choices.
It is your decision as to whether to have an invasive test or not. Your maternity care providers and fetal medicine team are here to provide support.
Your midwife and doctor are more than happy to answer any questions that you have, and we hope this information has helped you and your family.