Ngā whakamātau hauora mō te pūira kehe me ētehi atu āhuatanga Screening for Down syndrome and other conditions
During pregnancy you will be offered tests to check you and your pēpi (baby) are healthy. Your pēpi can be screened for Down syndrome and other conditions. If you choose to have this screening, you get these tests in your first or second trimester.
Conditions screening checks for
Screening checks the chance of your pēpi having:
- Down syndrome
- Edwards syndrome
- Patau syndrome
- other rare genetic disorders.
Down syndrome is a genetic condition where your pēpi has an extra chromosome 21. Babies with Down syndrome have 47 chromosomes instead of 46. This can change how your baby's body and brain develop, and can cause learning difficulties and health problems. Many of the health problems associated with Down syndrome can be treated.
Help and support is available for whānau who have a child with Down syndrome. People with Down syndrome attend school and take part in whānau and community life. Down syndrome is also called trisomy 21.
Down syndrome — Healthify (external link)
Edwards syndrome (also called trisomy 18) and Patau syndrome (also called trisomy 13) are rare conditions caused by extra copies of chromosomes. These conditions can lead to life-threatening complications that severely affect the brain, heart and kidneys. Most babies only live for a few months and need full-time care. (external link)
Other rare conditions may also be identified by screening. Your midwife or doctor will be able to give you information about these conditions.
Choosing whether to screen
Choosing whether to have this screening is an important decision. You need to have enough information to make the decision that is right for you. Some people will want to know if their pēpi has one of the conditions being screened for before they are born. Other people will decide not to have this screening.
Your midwife or doctor can give you information to help you decide.
HealthEd resources
Our HealthEd website has information for pregnant people to help you make an informed decision about optional screening and testing for Down syndrome and other conditions.
Antenatal screening and testing for Down syndrome and other conditions — HealthEd (external link)
Screening options
There are 2 screening options in Aotearoa New Zealand. These are for people who are less than 20 weeks pregnant:
- a blood test and an ultrasound (scan) — if you are less than 14 weeks pregnant
- a blood test — if you are between 14 and 20 weeks pregnant.
If you are less than 14 weeks pregnant
If you are less than 14 weeks pregnant, you can get a blood test and an ultrasound. You need to have both tests to get a result. While the blood test is free, you may have to pay for the ultrasound.
Blood test
It is best if you have the blood test at 9 to 10 weeks. But, you can take it between 9 weeks, and 13 weeks and 6 days.
Ultrasound (nuchal translucency scan)
It is best if you have the scan between 12 weeks, and 13 weeks and 6 days.
The scan measures the fluid at the back of your baby's neck. There tends to be more fluid if your pēpi has a condition.
This scan also checks:
- when your pēpi is due
- how your pēpi is developing
- if you are having a multiple birth (more than one pēpi).
If you are between 14 and 20 weeks pregnant
If you are between 14 and 20 weeks pregnant, your screening test is only a blood test. It is best if you take the blood test between 14 and 18 weeks. But, you can take it up until 20 weeks.
Screening results
To work out the chance of your pēpi having one of the screened conditions, your blood and ultrasound results are looked at with measurements such as:
- your age
- your weight
- how many weeks pregnant you are (your baby's gestational age).
When you will get the results
Your midwife or doctor will give you the results within 10 days of the tests.
Screening results are not perfect. You may be told your pēpi has a higher chance of having a condition when they do not have a condition. You may also be told your pēpi has a low chance when they do have a condition.
If your test shows an increased chance
Your midwife or doctor will discuss the results with you and answer your questions. You can also talk to organisations who help families with tamariki who have conditions.
Your midwife or doctor will also offer to refer you to a specialist to talk about further testing. This may include non-invasive prenatal screening (NIPS) or diagnostic testing.
Non-invasive prenatal screening
If you are referred to a specialist, they might offer you another test called non-invasive prenatal screening (NIPS). This is a blood test from you that gives more information about the chance of your pēpi having Down syndrome or another condition. If the result from NIPS is 'increased chance' you will be offered diagnostic testing to find out for certain if your pēpi has the condition.
Diagnostic testing
Diagnostic testing confirms if your pēpi has Down syndrome or another screened condition.
If you are thinking about diagnostic testing, talk to your midwife and the specialist about the tests and any risks before you decide.
Diagnostic tests look at a sample of your baby's cells. To collect the sample, a thin needle is inserted through your abdomen and into the placenta or fluid around your pēpi. A scan is done to guide the position of the needle.
Taking a fluid sample is called an amniocentesis. Taking a sample of the placenta is called chorionic villus sampling (CVS). Amniocentesis is the more common test.
There is a small chance of miscarriage with diagnostic testing. This happens in around 3 out of 1,000 procedures.
The test is usually done from 15 weeks of pregnancy. A specialist will use an ultrasound and insert a thin needle through your abdomen, into the uterus. They will take a small sample of the fluid that surrounds the fetus.
If your test confirms a condition, your midwife, doctor or specialist will talk to you about what this means and provide support. They will let you know about any other appointments you might need and will also be able to connect you with support services.
The test is usually done between 11 and 14 weeks of pregnancy. During the test, a needle is inserted through your abdomen and a small sample of cells is removed from the placenta.
If your test confirms a condition, your midwife, doctor or specialist will talk to you about what this means and provide support. They will let you know about any other appointments you might need and will also be able to connect you with support services.
