It may be worth asking the midwife what happens in your area and when you can expect to get your results. You will be offered an appointment to discuss the test results and the options you have. The charity Antenatal Results and Choices ARC offers lots of information about screening results and your options if you get a higher-chance result.
If the screening test shows that the chance of having a baby with Down's syndrome, Edwards' syndrome and Patau's syndrome is lower than 1 in , this is a lower-chance result. More than 95 out of screening test results will be lower chance. A lower-chance result does not mean there's no chance at all of the baby having Down's syndrome, Edwards' syndrome or Patau's syndrome.
If the screening test shows that the chance of the baby having Down's syndrome, Edwards' syndrome or Patau's syndrome is higher than 1 in — that is, anywhere between 1 in 2 and 1 in — this is called a higher-chance result. Fewer than 1 in 20 results will be higher chance. This means that out of pregnancies screened for Down's syndrome, Edwards' syndrome and Patau's syndrome, fewer than 5 will have a higher-chance result. A higher-chance result does not mean the baby definitely has Down's syndrome, Edwards' syndrome or Patau's syndrome.
If you have a lower-chance result, you will not be offered a further test. Whatever results you get from any of the screening or diagnostic tests, you will get care and support to help you to decide what to do next. If you find out your baby has Down's syndrome, Edwards' syndrome or Patau's syndrome a specialist doctor obstetrician or midwife will talk to you about your options. You can read more about what happens if antenatal screening tests find something.
You may decide to continue with the pregnancy and prepare for your child with the condition. Or you may decide that you do not want to continue with the pregnancy and have a termination. Video call. This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.
The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional. For more information, please visit the links below:. You are welcome to continue browsing this site with this browser.
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Why test for Down syndrome? There are two types of prenatal tests for Down syndrome: Screening tests: These do not give you a definitive answer, but let you know if your baby is at increased chance of Down syndrome. Screening tests do not harm the mother or baby. Diagnostics test: These are very accurate, giving you a definitive answer. Diagnostic tests are usually offered to women whose babies are at increased chance, based on the result of the screening tests.
Screening tests There are 3 types of screening test for Down syndrome: the combined first trimester screening, the non-invasive prenatal testing NIPT , and the second trimester maternal serum screening.
Combined first trimester screening The combined first trimester screening test is done between 9 weeks and 13 weeks plus 6 days into the pregnancy to calculate the chance of a number of abnormalities, including Down syndrome.
Facts about Down syndrome. Centers for Disease Control and Prevention. Frequently asked questions. Prenatal genetic diagnostic tests.
American College of Obstetricians and Gynecologists. Ostermaier KK. Down syndrome: Management. Down syndrome: Clinical features and diagnosis. Accessed Jan. Gabbe SG, et al.
Genetic screening and prenatal genetic diagnosis. In: Obstetrics: Normal and Problem Pregnancies. Philadelphia, Pa. Rink BD, et al. Screening for fetal aneuploidy. Seminars in Perinatology. Bunt CW, et al. The role of the family physician in the care of children with Down syndrome. If the baby has Down's syndrome, the levels of these substances can be affected. Again, a computer program is used to give the risk of the baby having Down's syndrome, based on the blood test results, your age, the stage that you are at in your pregnancy, your weight, ethnicity and smoking status.
The blood test used in Down's syndrome screening is also sometimes called serum screening. You should ask your doctor or midwife how long the results will take and how you will receive them. The results can take up to two weeks. As mentioned above, the screening test will give the risk in this pregnancy of the baby being born with Down's syndrome. For example, the test may show that there is a 1 in 1, risk of having a baby with Down's syndrome.
This means that for every 1, pregnant women, one will have a baby born with Down's syndrome and will have a baby born without Down's syndrome. So, this would be quite a low risk. In the UK, the National Screening Committee has suggested a cut-off level to differentiate between screening test results with a higher risk that the baby is born with Down's syndrome and those with a lower risk.
The cut off is 1 in This means that if your screening test results show a risk of between 1 in 2 to 1 in that the baby has Down's syndrome, this is classified as a higher risk result. If the results show a risk of 1 in or more, this is classified as a lower risk result.
The higher the second number gets, the lower the risk becomes the less likely you are to have a baby with Down's syndrome. So, when you are given your results, you will be told whether this is a lower risk or a higher risk result. Most women who have a screening test for Down's syndrome will have a lower risk result.
If this is the case, you can be reassured by this. This does not mean your baby definitely does not have Down's syndrome although the likelihood that this will happen is very small. In some cases, the baby does have Down's syndrome this is called a 'false negative' result.
If you have been given a higher risk result, this does not mean your baby definitely has Down's syndrome. If you are given a higher risk result, further tests are needed to confirm the diagnosis and give a definite 'yes' or 'no' answer see below. In cases where the baby does not have Down's syndrome, this is called a 'false positive' result. You can still choose whether or not you want to go ahead with the diagnostic test at this stage.
You can still say no. The two main tests that are used to diagnose Down's syndrome before birth prenatally are amniocentesis and chorionic villus sampling also called CVS. In both tests samples are taken from the inside of your womb with a needle usually passed through your tummy. There is a small risk of miscarriage in both tests.
CVS can be done earlier in pregnancy than amniocentesis. Both tests are discussed further in separate leaflets. Read about amniocentesis and about chorionic villus sampling CVS. For example, you may be given another appointment or sometimes results are given by telephone.
There are two main tests that can be done to look at the baby's chromosomes after amniocentesis or CVS. The first is called a rapid test. This usually gives results within three days after CVS. This test just looks for the chromosomal disorders Down's syndrome, Edwards' syndrome and Patau's syndrome.
Sometimes sex chromosome disorders such as Turner syndrome can also be detected on a rapid test.
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