What is the 12-week scan for?

When you’re between 11 and 14 weeks pregnant, you’ll be offered an ultrasound scan. The purpose is to estimate the gestational age of your baby, and check for multiple pregnancy (NICE, 2021). If you opt for it, the scan will also screen for Down's syndrome, Edwards' syndrome and Patau's syndrome (NICE, 2021).

The scan builds a picture from the way high-frequency sound waves from a probe passed over your tummy reflect off your baby in your womb (NHS, 2020). This creates a 2D image and, based on your baby's size, your carer will estimate the gestational age of your baby and the estimated due date (NHS, 2020; NICE, 2021). 

Is it safe?

Scans are painless for you, and have no known side effects on babies (RCOG, 2015; NHS, 2020). 

Some parents pay for ultrasound images or videos for non-medical reasons. These scans are often in 4D, which uses higher energy sound waves than 2D, and they are not recommended until the second half of pregnancy (RCOG, 2015).

During the first 10 weeks of pregnancy, ultrasound should only be used for clinical reasons (RCOG, 2015). This is because the baby is very tiny and may be vulnerable (RCOG, 2015). 'Souvenir' scans have no medical benefit, and are not recommended by health professionals (Salvesen and Lees, 2009).

Does everyone have a scan?

All screening tests are optional, and only the person carrying the baby can decide to accept or decline them. When you first find out you’re pregnant, your midwife or GP should give you a booklet called ‘Screening tests for you and your baby’. This gives you detailed information about the types of scan offered and what they look for (Public Health England, 2021a). It should help you decide whether you want to have a scan.

Because the scan can indicate that your baby might have a health condition, you need to consider whether that information will affect your plans to continue this pregnancy. If a positive result would make no difference to your plans, you may feel you don't need these tests (NHS, 2021b).

Midwives and consultants can offer alternatives to ultrasound scans, such as using a Pinard stethoscope to listen to your baby’s heartbeat.

Why might I decide to have a 12-week scan?

Scans are useful for telling you about your unborn baby. They can:

• check the estimated size and age of your baby
• check how many babies you’re having
• show the position of your baby (at the time of the scan)
• show the position of the placenta (which might affect plans for the birth)
• check that your baby is growing normally.

(NHS, 2020)

Can the 12-week scan show your baby's sex?

Finding out the sex of your baby is not offered as part of the 12-week scan.

Do you get a picture at the 12-week scan?

Some hospitals can offer you a picture of your baby, usually for a fee.

When will I be offered my first pregnancy scan?

The NHS offer all pregnant women two ultrasound scans during their pregnancy. The first is between 11 and 14 weeks (NHS, 2020; NICE, 2021). To read about the second scan, see our article What happens at your 20 week scan?

Who can go with me?

You’ll be invited to attend with your partner, another family member or birth partner. During the COVID pandemic, it has not always been possible to have a partner with you, mainly because the scan rooms are too small for social distancing. You might both be asked to wear a mask.

Children are not encouraged to attend. So try to get childcare for any older kids while you have your scan (NHS, 2020). 

What happens during a scan?

Scans usually take place in a hospital. Before the scan, you’ll be sent a letter confirming the appointment, with instructions of where to go and what's required. Most scans are carried out by a sonographer who has been specially trained. The process usually takes 20 to 30 minutes (NHS, 2020) but it's best to allow more time because there can be a long wait.

At the appointment, you’ll probably be asked to drink a lot of water (NHS, 2021). This helps to inflate your bladder, which makes it easier for the sonographer to see your baby. Then you’ll be invited into a private room with a bed and asked to lie down. The sonographer will ask you to uncover your stomach by lowering your trousers or skirt to your hips and raising your top over your belly (NHS, 2020). You might find it easier not to wear tight-fitting clothes that are hard to pull up.

The sonographer will put ultrasound gel on your stomach, tucking tissue paper around the top of your trousers or skirt to protect them. The gel might feel cold but it helps the probe to move smoothly over your skin (NHS, 2020).

The sonographer will guide this probe over your tummy using a little pressure but it won’t hurt. The images of your baby will appear in black and white on the screen of the ultrasound (NHS, 2020).

The sonographers will have the ultrasound screen angled so they can examine your baby carefully during the scan (NHS, 2020). But they might be able to turn the screen to show you the moving pictures. You and anyone else with you might be able to hear the heartbeat.

When will I find out the results?

The sonographer will tell you what’s happening during the scan.

If the scan shows something that concerns the sonographer, they might ask one of their colleagues for a second opinion. You might also be offered further tests. You should be given information about any further tests and be invited to discuss your options with your midwife and or a consultant.

What are the pros and cons of having a scan at 12 weeks?

Advantages of having a scan at 12 weeks can include:

• earlier detection of some conditions (if you opt into that screening) and better management of any pregnancy complications
• early scans can detect more than one baby
• scans can help estimate the due date, which might prevent unnecessary inductions if the baby is wrongly thought to be overdue.

(Salvesen and Lees 2009; Buckley, 2016; NICE, 2021; ARC, no date)

Remember though that scans:

• can identify but cannot improve some adverse outcomes for babies. It is extremely rare that babies with major abnormalities can be treated in the womb – the only option is to choose to continue or terminate the pregnancy
• might increase your uncertainty and anxiety about the health of your baby.

 (NICE, 2008; Salvesen and Lees 2009; ARC, no date)

How will a dating scan test for possible genetic differences?

All pregnant women in England are offered a screening test for Down’s syndrome, Edward’s syndrome and Patau’s syndrome. This is called the combined test because it combines a blood test with the 12-week ultrasound scan (NHS, 2021b).

If you choose to have it, you’ll have a blood test and the fluid at the back of your baby’s neck will be measured during the ultrasound scan (NHS, 2021b).

Even if you choose not to have the screening test, any scan during your pregnancy may pick up indicators of a condition your baby might have.

What if the scans show a possibility of one of these conditions?

If the scans show a higher chance of Down’s syndrome, Edward’s syndrome or Patau’s syndrome, you have the option to:

• not have any more testing
• have a second screening blood test, called the non-invasive prenatal testing (NIPT), which gives a more accurate screening result to help you decide whether you want a diagnostic test
• have a diagnostic test.

(NHS, 2021b)

NIPT can screen for all three conditions, Down’s syndrome only, or Edwards’ syndrome and Patau’s syndrome only (NHS, 2021b). As it is a blood test, it carries no risks for your baby. After the screening you can decide what to do next.

Diagnostic tests include amniocentesis and chorionic villus sampling (CVS). Both amniocentesis and CVS carry a very small risk of miscarriage (Public Health England, 2021b; ARC, no date).

To find out more about the lived experience of having Down's syndrome, have a look at PADS, which is written by parents and young people with Down's syndrome to show the reality of their lives.

What happens if I’m worried about the results of the scan?

If you have any concerns or the sonographer finds any anomalies, they have special training to talk with you about what could be a hard and worrying subject. You’ll also be able to discuss things with a doctor within a few days if you do receive difficult news. You will also be offered further scans as sometimes a suspected anomaly is identified but upon closer inspection is found not to be an issue (ARC, no date).

What else might I need to know?

Normally, if screening or diagnosis find that your baby has a condition, this will be shared with a national register (Public Health England, 2021a). You can find out more about this register or opt out of it here (Public Health England, 2021a).

Where can I get extra support or information?

A range of services offer support:

• Antenatal Results and Choices (ARC) has a national helpline 020 7713 7486 and more information on their website.
• For information about life with a child or young person with Down syndrome, visit www.positiveaboutdownsyndrome.co.uk
• If you have a high chance/confirmed result your baby has Down syndrome a warm welcome awaits you here. 
• SANDS support for baby loss.
• Support for parents of a baby with Down's syndrome.
• Support for parents with premature or poorly babies.

This page was last reviewed in January 2022

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700.

We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.

Make friends with other parents-to-be and new parents in your local area for support and friendship by seeing what NCT activities are happening nearby.