Future Options in pregnancy
This information has been written primarily for the following people affected by Spinal Muscular Atrophy (SMA):
- Couples who have had a child with SMA
- Couples who know that one or both of them are carriers of SMA
- Couples where one or both of them have SMA
- Couples who know SMA has occurred in their extended family
If one of these applies to you and you are thinking of having children, or you or your partner are currently pregnant, then there are a number of options that may be available to you. The decision about which option to choose is a very personal one. There are no right or wrong decisions to be made and you will want to reach a conclusion that is right for you, based on the information supplied by the health professionals supporting you.
The different options available to you, and funding for them, may be limited by your particular genetic, family and individual circumstances, as well as the type of SMA so it’s important to consult a genetic counsellor to find out what your choices are.
You should be offered, or can request from your G.P., a referral for genetic counselling. A genetic counsellor will answer any questions you have regarding your particular genetic circumstances and they will also provide you with advice and information. There is more on genetic counselling later in this leaflet, along with other sources of support and information.
If you would like to read more about the genetics of SMA, the leaflet ‘The Genetics of Spinal Muscular Atrophy’ can be downloaded from SMA Support UK’s website here as can ‘The Genetics of Some Rarer Forms of Spinal Muscular Atrophy’ by clicking here. Or you can request printed copies from our office.
The following options may be available to you:
- Natural conception with no testing
- Egg or sperm donation – the donor is tested to check that s/he is not a carrier of SMA
- Non-Invasive Prenatal Diagnosis (NIPD) – DNA samples are tested from the 8th week of pregnancy to find out if the baby has SMA
- Chorionic Villus Sampling (CVS) – a sample of the placenta is genetically tested between the 11th and 14th weeks of pregnancy to find out if the baby has SMA
- Amniocentesis – a sample of amniotic fluid is genetically tested between the 15th and 20th weeks of pregnancy to find out if the baby has SMA
- Preimplantation Genetic Diagnosis (PGD) – a process similar to IVF which involves collecting eggs from the woman, fertilising them outside the body and then testing the embryos for SMA
This leaflet focuses on four of these possible options – Non-Invasive Prenatal Diagnosis (NIPD), Chorionic Villus Sampling (CVS), amniocentesis and Preimplantation Genetic Diagnosis (PGD). It also includes two personal experiences written by individuals, one who has had CVS and the other who has had PGD, along with some commonly asked questions.
Non-Invasive Prenatal Diagnosis (NIPD)
This new type of testing does not have a miscarriage risk and is available from September 2016. An application for the test to be funded by the NHS for eligible patients is in process. In the meantime, your G.P. or local genetics centre will be able to advise you on funding / charges for NIPD in your area.
NIPD has become possible following the discovery that there is a small amount of a baby’s genetic material, known as cell-free fetal DNA, present in a pregnant mother’s blood. There is enough cell-free fetal DNA in the mother’s blood from around the 8th week of pregnancy so NIPD testing can take place any time from then.
The test can be used in pregnancies with a 1 in 4 risk of SMA, where both parents are carriers of SMA and have previously had a child with genetically confirmed SMA. There must also be DNA available from the affected child (see below). Twin pregnancies cannot be tested using NIPD.
NIPD works by extracting and testing the unborn baby’s DNA from a sample of the pregnant mother’s blood. Samples of DNA are also required from the father of the baby and their previously affected child. For both of these it is likely that there are stored samples in the laboratory if previous testing has been undertaken for a diagnosis of SMA in the child and to confirm SMA carrier status in the father. If this is the case then new samples will not be needed. All three of these samples are used in the testing process; without them NIPD testing is not possible.
The NIPD testing will determine whether the foetus (unborn baby) has inherited the affected or unaffected copy of the SMN1 gene from each parent and whether or not the foetus has SMA. The test cannot determine what type of SMA the foetus has.
The NIPD result could be available within 7-10 working days but you can check this with your genetic counsellor who will also go through the result with you. You will be given information and support before, during and after you get the result to help you decide what to do next. Your options at this point will be to continue with the pregnancy or, depending on where you are in your pregnancy, to have a termination.
It is estimated that in approximately 5% of cases, the test may not return a result. If this happens the test may be repeated or an alternative invasive test (CVS / amniocentesis) may be carried out. It is also estimated that the risk of misdiagnosis, due to technical and biological reasons, when using NIPD is very low (approximately 1 in 500-1000).
NIPD laboratory testing for SMA is carried out at the West Midlands Regional Genetics Laboratory in Birmingham. However, access to the testing and genetic counselling will be through your local genetics centre, wherever you live in the UK.
A genetic counsellor will be able to provide you with more information about NIPD and can organise the test. A referral to discuss testing can also be made to your local genetics centre by a G.P., midwife or obstetrician. Genetics centres welcome the opportunity to meet with you to talk about all your testing options in pregnancy prior to conception, or as early in your pregnancy as possible.
Chorionic Villus Sampling (CVS)
CVS involves taking a sample of the placenta and testing the cells for SMA. This is usually done between the 11th and 14th weeks of pregnancy and involves either inserting a needle through the abdomen (transabdominal CVS) or inserting a tube through the cervix (transcervical CVS). Both of these processes are guided by an ultrasound scanner. There is generally a 1-2% risk of miscarriage as a result of having CVS.
The sample is sent to a laboratory and genetically tested for SMA. You may need to ask how long it will take for you to get the results and how you will be informed. You will be given information and support before, during and after you get the results to help you decide what to do next. Your options at this point may be to continue with the pregnancy or to have a termination.
A personal experience of CVS
“I found that the genetics nurse was very helpful in liaising between the laboratory, the hospital and us. It's worth asking to have a dating scan at around 8 weeks, as this will confirm the dates are approximately correct and reduce the possibility of being disappointed on the arranged date of the CVS test. My consultant didn't use a local anaesthetic, as some do, and the first CVS test was quite painful. The second one was merely uncomfortable in comparison -¬ every pregnancy is different. The CVS results took approximately a week. When we had a bad CVS result it was devastating, but it was still in a way a relief that the waiting was over and we could get on with trying again. I believe that nothing is as bad as losing a child and this enabled me to go through with a termination, knowing that I wouldn't have to watch another baby die. In time, we finally had a good CVS result. I was in shock to start with, even though my partner was celebrating as soon as we heard. 6 months later, we got the child we'd been waiting for. Although it will never take away the pain of losing our first born, our new baby has brought joy and happiness back into our lives.”
For more information on CVS
For more information on CVS, what the procedure involves and the possible risks, please see the following:
Amniocentesis is a way of testing to find out if an unborn baby (foetus) has a serious health condition. Amniocentesis usually takes place during weeks 15-20 of the pregnancy and involves putting a needle through the abdomen to remove some amniotic fluid (the fluid that surrounds the foetus) from the womb. There is generally a 1-2% risk of miscarriage as a result of having amniocentesis.
The cells in the amniotic fluid will then be sent to a laboratory and genetically tested for SMA. You may need to ask how long it will take for you to get the results and how you will be informed. Amniocentesis test results can take longer than CVS results.
You will be given information and support before, during and after you get the results to help you decide what to do next. Your options at this point may be to continue with the pregnancy or to have a termination.
For more information on Amniocentesis
For more information on amniocentesis, what the procedure involves and the possible risks, please see the following:
Preimplantation Genetic Diagnosis (PGD)
PGD may not be available to every couple. There are eligibility criteria for both the PGD process and for NHS funding. These overlap so some couples may meet one set of criteria but not the other, neither, or both. Different PGD centres may also have different criteria.
There are two steps involved in PGD. The first step is to create, biopsy (take a sample of tissue so that it can be examined more closely), and test the embryos (a baby in the very early stages of development). The second step is to transfer embryos which do not have SMA into the womb.
Even though most couples who have PGD are able to become pregnant naturally, in vitro fertilisation (IVF) is used to produce embryos for testing. This involves using fertility drugs to stimulate the ovaries to produce several eggs which are then collected. Sperm is then used to fertilise the eggs in the laboratory. Eggs which are successfully fertilised become embryos. Once the embryos have grown into balls of cells (‘blastocysts’) a small sample of cells is very carefully removed (the embryo ‘biopsy’). After the biopsy, the embryos are rapidly frozen (vitrification) while the genetic test is performed on the cells taken from the embryos. Genetic testing takes around two weeks to complete.
Once the genetic test is completed, and providing the results show that there is at least one embryo that does not have SMA, this embryo can then be selected, warmed and transferred into the womb. A pregnancy test is carried out 12 days later to see whether the PGD treatment has been successful.
A personal experience of PGD
“Our son Daniel was diagnosed with SMA Type 2 when he was 9 months old. As much as the diagnosis itself was a shock, the thought of potentially having more children with the same condition was devastating for us. After a lot of thought and reading through the various information available we asked to be put on the waiting list for PGD. The medication routine for the IVF part of the process was relatively simple and much easier than I had thought even though it involved me sticking needles into myself. The part that I was most nervous about beforehand was the egg collection but, with a lot of reassurance from the medical staff at the hospital and sedative medication, it all went very well and I did not feel any pain at all. I cannot remember details of how many eggs they were able to collect or how many were fertilised but in the end I know there was only one embryo that was healthy and suitable for implantation. The hardest part of the process however was not the medical procedures that we went through but the emotional rollercoaster ride that I was on during the time I was taking the IVF medication as my hormones and my moods were all over the place. My husband and I didn’t dare to hope that I would fall pregnant on our first treatment round but that is exactly what happened and finally a little baby girl was born and we named her Sophia. The journey has not been easy but Daniel and Sophia are worth it.”
For more information on PGD
For more information on PGD please see the following:
Q: Is it too late to get genetic counselling and discuss my options if I am already pregnant?
A: Having genetic counselling before pregnancy will give you and your partner more time to think about genetic testing and the possibly difficult decisions this can raise. But do not be afraid to seek genetic counselling if you are already pregnant. You can contact your G.P. or your medical team to ask for an urgent genetic counselling referral. If this is not possible, you can contact your local genetic service directly (a list of centres is available on the British Society for Genetic Medicine website: www.bsgm.org.uk).
Q: How can I find out if I am eligible for PGD?
A: More information on PGD is available from the Human Fertilisation and Embryology Authority. Their website is: www.hfea.gov.uk/treatments/embryo-testing-and-treatments-for-disease/pre-implantation-genetic-diagnosis-pgd/ Your genetic counsellor will also be able to give you more information and if you are referred to a PGD centre then they will go through their specific criteria with you.
Q: Do you get test results quicker with amniocentesis or CVS?
A: The results following amniocentesis do tend to take longer than for CVS and CVS can be done earlier in the pregnancy. If you decide to have a termination following amniocentesis then this time difference can mean that a different type of termination is performed due to the potentially later stage of the pregnancy.
Q: Is genetic testing 100% accurate?
A: You can ask your genetic counsellor for more information on this. As a general rule, 100% accuracy cannot be guaranteed but measures are taken to try and ensure that genetic test results are as close to 100% accuracy as possible.
Q: If we choose to conceive naturally and not have any testing before our baby is born, can we have testing after the birth?
A: Genetic testing of your baby shortly after birth can be requested to confirm whether or not your baby has SMA. You may wish to ask your medical team or genetic counsellor for more information on this and to discuss the pros and cons before you become pregnant.
Q: If the tests show that my unborn baby has SMA, can they tell what type of SMA it is?
A: A positive test for SMA is not currently able to distinguish between the 3 different childhood onset types of SMA – Type 1 (severe), Type 2 (intermediate) and Type 3 (mild). If you already have a child with SMA and your unborn baby also has SMA then it is likely, but not certain, that your unborn baby will also have the same type of SMA.
Q: How can we find out what the chances are of us having a baby with SMA?
A: The chances of having a baby with SMA vary depending on the type of SMA in your family and whether you or your partner have SMA or are carriers. Your genetic counsellor will be able to give you information relevant to your individual circumstances. For a general overview of the genetics of SMA Types 1, 2 and 3, please click here. For information on the genetics of some rarer forms of SMA please click here.
Q: SMA has occurred in my extended family. My boyfriend and I are thinking of having children. How can I find out if I am a carrier?
A: You can ask your G.P. to refer you and your partner to your regional genetics centre for genetic testing. If you would like to find out more about your nearest genetic service please click here. For more detailed information on the genetics of SMA please click here. Or for information on the genetics of some rarer forms of SMA please click here.
Sources of Support:
- Genetic Counselling
You should be offered genetic counselling before, during and after the genetic testing process. You can also request a referral from your G.P.
Genetic counselling takes place with a healthcare professional who has expert training in genetics. Before testing, they will answer any questions you have regarding your genetic circumstances and they will provide you with advice and information about your options to assist you with making your own decisions. Genetic counselling will also look at the emotional impact of test results and discuss what the next steps might be for you and your family.
Your genetic counselling appointment may take place at your nearest NHS Regional Genetics Centre. For information on each of the centres in the UK, please see The British Society for Genetic Medicine.
- Antenatal Results and Choices (ARC)
ARC is a national charity helping parents and healthcare professionals through antenatal screening and its consequences. They offer non-directive information and support to parents: before, during and after antenatal screening; if they are told their baby has an anomaly; when they are making difficult decisions about continuing with or ending a pregnancy; when they are coping with complex and painful issues after making a decision, including bereavement. ARC’s helpline is available Monday to Friday 10.00am to 5.30pm, 0845 077 2290 from a landline and 0207 713 7486 from a mobile. The website is: www.arc-uk.org
- Miscarriage Association
Information and support for anyone affected by miscarriage. Helpline: 01924 200 799 Monday to Friday 9am-4pm. Website: www.miscarriageassociation.org.uk
- SMA Support UK
SMA Support UK provides free, confidential information and support to anyone affected by SMA. We do not offer a counselling service and are not experts in terms of future pregnancy options but we are always willing to listen and offer emotional support.
You can contact SMA Support UK by phone: 01789 267 520
By email: email@example.com
We have a number of other information sheets and resources available to download from our website or hard copies can be requested by phoning or e-mailing the support services team.
Our thanks to Alison Lashwood, Consultant Genetic Counsellor and Clinical Lead in PGD, who works at the Centre for Preimplantation Genetic Diagnosis (located in Guy’s and St. Thomas’ Hospital, London) for the information on PGD (www.pgd.org.uk). Also to Dr Stephanie Allen and Julie Hewitt from the West Midlands Regional Genetics Laboratory for the information on NIPD.
Author: SMA Support UK Information Production Team
First Published: August 2015
Reviewed: September 2017
Full review due: September 2018
This leaflet received a commended certificate in the 2016 British Medical Association (BMA) Patient Information Awards.
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