Introduction to antenatal screening tests
Your choices in pregnancy
During your pregnancy, you will be offered a number of different screening tests. This leaflet contains important information about antenatal screening and testing. The information in this leaflet will help you decide whether to have, or not have, some or all of the tests. You will have the chance to talk about the tests with your midwife and doctor.
The NHS keeps the results of all tests confidential. Hospital policies vary on how many people have access to your test results. Your midwife will be able to explain the local arrangements that will apply to you.
Your NHS number is unique to you and this number identifies you on NHS computer systems. If you have a copy of your NHS number, please have the number available when you first see the midwife or go to the hospital for your maternity care.
What are screening tests?
What tests are available?
Deciding if you want to have the tests
Welsh Congenital Anomaly Register and Information Service (CARIS)
What are screening tests?
Screening tests can help to detect some of the conditions that may affect either you or your baby. They do not show for certain whether you or your baby are affected. They show what chance there is that you or your baby are affected.
If the result of a screening test shows you have a higher chance of having a certain problem, you will be offered a diagnostic test. Diagnostic tests give more certain results, but with some there is a risk of miscarriage. For this reason, they are only offered to women with a higher chance of having a problem.
As with all medical tests, the results of screening and diagnostic tests are not 100% accurate.
What tests are available?
You will be offered the following screening tests.
Usually between 11 to 13 weeks
An ultrasound scan to see:
- how many weeks pregnant you are;
- if the baby’s heart is beating; and
- if you are having more than one baby.
In early pregnancy, usually before 13 weeks
You will be offered blood tests to detect:
- infections that could harm your baby, these are HIV, hepatitis B and syphilis;
- your blood group and Rhesus group, and whether there are any antibodies in your blood;
- certain blood disorders which are inherited, such as sickle cell and thalassaemia; and
- if you are protected against rubella (German measles).
All of these tests can be taken at the same time. You can choose which tests are carried out. Your midwife will tell you where the tests can be done.
At 15 to 18 weeks
Testing for Down’s syndrome
You can have a blood test to find out your chance of having a baby with Down’s syndrome. The test can be done from 15 weeks of pregnancy.
At 18 to 20 weeks
You can have an ultrasound scan to see if there are any problems with the way your baby is developing.
Deciding if you want to have the tests
It can be difficult to decide what tests to have. Some women do not want to know if they have any infections that could affect the baby or if there are problems with the way the baby is developing. Others want to know so they can protect their baby against infections or, if there are major problems with the baby, they can think about whether they want to end the pregnancy.
Take time to think before you decide. You can talk about the tests with your midwife and doctor, and ask any questions you may have. There are also leaflets available in this pack with more information about each test.
When you have chosen which tests you want to have, the midwife will make arrangements for you. She will also explain how you will get the results. The results of all screening tests are confidential.
If you change your mind
You can change your mind about your choices. If you decide to have a test and then change your mind before you have the test, please remember to tell your midwife so she can make a note in your maternity records.
Your antenatal screening choices
Please use this form to make a record of your choices about what tests you want to have (antenatal screening choices).
| Test |
Yes, I am interested in having this test. |
No, I am not interested in having this test. |
I don't know. I would like more information. |
| Early pregnancy ultrasound scan |
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| Screening for HIV |
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| Screening for hepatitis B |
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| Screening for syphilis |
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| Screening for rubella |
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| Screening for blood group and antibodies |
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| Screening for sickle cell and thalassaemia |
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| Screening for Down’s syndrome |
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| Fetal anomaly ultrasound scan |
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Please remember that:
- you choose which tests you want to have;
- no test will be done unless you agree; and
- if you do not come for a test, you will not be sent a reminder.
More information
In your folder, you should have leaflets about:
- infections and pregnancy;
- your blood group and pregnancy;
- ultrasound scans in pregnancy;
- screening for Down’s syndrome in pregnancy; and
- screening for sickle cell and thalassaemia in pregnancy.
You can also get more information about screening tests from your midwife or your hospital doctor (your obstetrician) and from the Antenatal Screening Wales website at: www.antenatalscreening.org.
Welsh Congenital Anomaly Register and Information Service (CARIS)
CARIS is the Welsh Congenital Anomaly Register and Information Service.
CARIS collects information about problems with the way babies develop in pregnancy. These problems are called congenital anomalies, malformations or birth defects. They include problems such as Down’s syndrome, heart defects or cleft lip.
It is very important to know more about these sorts of problems and their causes.
CARIS uses the information to find out how common these problems are. The information CARIS collects also helps to show how good health services are at picking up these problems.
If it is suspected from your screening tests that there is this type of problem with your pregnancy, the midwife or doctor will pass information about this to CARIS.
The information held on the CARIS register is strictly confidential. We will never pass your name to anyone else or publish it.
If you do not want your midwife or doctor to pass information about you or the baby to CARIS, please tell your midwife and she will write this in your notes and tell CARIS that you do not want them to use your information. |
