Screening for Down's syndrome, Edwards' syndrome and Patau's syndrome is offered to find out how likely it is that your baby has any of these 3 conditions:

• Down's syndrome (trisomy 21)
• Edwards' syndrome (trisomy 18)
• Patau's syndrome (trisomy 13)

It's the best way to find any of these conditions, but having screening is your choice.

Some people want to find out if their baby has one of the conditions and some do not. It may lead to very personal decisions about your pregnancy.

You can discuss the test with health professionals and decide, based on your own circumstances, if you want to have it.

Down's syndrome, Edwards' syndrome and Patau's syndrome screening is offered if you're pregnant.

It's usually done when you're between 10 and 14 weeks pregnant.

The first screening test for Down's syndrome, Edwards' syndrome and Patau's syndrome is called the combined test.

There are 2 parts to the combined test:

• a blood test when you're between 10 and 14 weeks pregnant, with blood taken from your arm
• an ultrasound to measure the fluid at the back of your baby's neck during your 12-week scan (dating scan), when you're between 11 and 14 weeks pregnant

If you choose to have the combined test, the 2 parts are usually done at the same time, although they may be done separately.

The quadruple test

If you're more than 14 weeks pregnant, you'll be offered the quadruple (quad) test instead.

This is a blood test done when you're between 14 and 20 weeks pregnant. The quad test checks for Down's syndrome but is not as accurate as the combined test.

Edwards' syndrome and Patau's syndrome will also be checked for during your 20-week screening scan, if you choose to have it.

There are no known risks to you or your baby from the blood tests or scans for Down's syndrome, Edwards' syndrome and Patau's syndrome.

You'll usually be given information about screening for Down's syndrome, Edwards' syndrome and Patau's syndrome at your first midwife appointment (sometimes called your booking appointment).

You can choose to check for:

• all 3 conditions
• Down's syndrome only
• Edwards' and Patau's syndromes only – these are always done as a joint test
• none of the conditions

Your midwife or doctor may book the appointments for you or tell you how to book the appointments yourself.

The screening is offered to everyone who's pregnant, but it's your choice if you want to have it.

It's the best way to see if there's a higher chance your baby has any of the conditions, but not everyone wants this information.

If you decide not to have the screening but change your mind later, speak to your midwife or GP. They can tell you if you're still able to have it.

You should get the results of Down's syndrome, Edwards' syndrome and Patau's syndrome screening within 2 weeks of having the tests.

You may get them by letter, or someone may contact you by phone or in person, depending on what the result is.

The possible results are:

• lower chance of the condition – most people will get this result
• higher chance of the condition

You'll get a single result for Down's syndrome, and a joint result for Edwards' syndrome and Patau's syndrome. You'll only get the results you asked for when you decided to have the test.

Antenatal Results and Choices (ARC) offers support and information about screening tests and how you might feel if you're told your baby has or might have a condition.

• ARC: Screening for Down's syndrome, Edwards' syndrome and Patau's syndrome
• Helpline: call 020 7713 7486, Monday to Friday, 10am to 5.30pm
• Text: 07908 683004
• Email: info@arc-uk.org