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If you are pregnant in England, you will be offered two ultrasound scans:

  • One ultrasound scan at around 11 to 14 weeks of pregnancy
  • One ultrasound at around 18 to 21 weeks of pregnancy

If there is a medical reason, you may be offered additional scans throughout your pregnancy.

What to expect at your 11 to 14-week scan

The 11 to 14-week scan, also referred to as the dating/nuchal scan or 12-week scan, is to check the following:

  • How many weeks pregnant you are and work out your due date (the estimated date of delivery or ‘EDD’)
  • Whether you are expecting more than one baby
  • That the baby is growing in the right place
  • Your baby’s development

The test should only take around 20 minutes to complete.

Screening test for syndromes

The 11 to 14-week scan may also be part of a combined screening test for Down’s Syndrome, Edward’s Syndrome and Patau’s Syndrome. This is to assess your chances of having a baby with one of these conditions.

The combined screening test involves a blood test and measuring the fluid at the back of the baby’s neck (nuchal translucency) during the scan.

You will only receive a combined screening test if:

  • You have made an informed decision to have the test and consent has been obtained
  • The pregnancy is between 11 to 14 weeks with the crown rump length (CRL) measurement of the baby between 45.0mm and 84.0mm

Combined screening cannot be performed if the baby’s size is outside of this range. If you are in the earlier stages of your pregnancy, you will be offered a rescan at 11 to 14 weeks of pregnancy.

If you are between 14 to 20 weeks of pregnancy, you will be offered a different blood test, called the quadruple test, to assess your chances of having a baby with Down’s Syndrome. However, this test is not as accurate as the combined test and cannot test for Edward’s or Patau’s syndromes.

You can discuss the above information with your midwife and find out more about the screening tests available via this link >

What to expect at your 18 to 20-week scan

The 18 to 20-week and 6 days scan, also referred to as the anomaly scan or 20-week scan, is to check the physical development of your baby.

Please note that this scan cannot pick up every condition and a sonographer (who carries out the ultrasound scan) will discuss any concerns with you. In some cases, you may be referred to a specialist team if a problem is suspected.

The scan usually takes about 30 minutes and you will also have the opportunity to identify the sex of the baby, if this can be identified clearly in the scan.

Sometimes it can be difficult to get a clear view of your baby or occasionally, checks cannot be completed because the baby is lying in an awkward position, if you are above the average weight, or if you have abdominal scarring from surgery, for example.

If this happens, it does not mean that there is anything to worry about, you will be offered one further scan by 23 weeks of your pregnancy.

If the 23-week scan is incomplete, please be assured that you will be offered a full physical examination for your baby after birth.

You can discuss the above information with your midwife and find out more about the screening tests available via this link >

What are viability scans?

If there are medical concerns with your pregnancy you may be offered a viability scan which will check the wellbeing of your early pregnancy. These are emergency scans, most commonly arranged via the early pregnancy unit. They usually last less than 20 minutes.

What are growth scans?

Growth scans may be offered to you after 28 weeks, if there is a health reason that may mean your baby has a higher chance of not growing well.

The scan is primarily to check baby’s growth and wellbeing, and is used alongside other tests to make clinical decisions about the best way to manage your pregnancy. A growth scan usually takes around 20 minutes.

What happens at a scan?

All scans are carried out by specially-trained member of staff, called a sonographer, or midwife sonographer. In order for the sonographer to obtain images of your baby, the scan is carried out in a dimly-lit room and you will need to have a partially-filled bladder.

  • You will be asked to lie on a couch
  • You will be asked to adjust your clothing so that the ultrasound gel can be placed on your stomach
  • Tissue paper will be tucked around your clothing to protect it from the ultrasound gel, which will then be put on your stomach
  • The sonographer passes a hand-held probe over your skin to examine the baby’s body. The gel ensures there is good contact between the probe and your skin surface

The scan should not hurt, but the sonographer may need to apply slight pressure to get the best views of your baby. This might be uncomfortable, but please let the sonographer know if you are in pain.

A 2D black and white picture of your baby will then be seen on the ultrasound screen.

The scan is a medical examination and you will be asked to give your permission before the scan is carried out. Our team will explain what is going to happen so that you feel comfortable and reassured throughout, however please feel free to ask any questions that you may have.

The sonographer will need to concentrate and may be quiet at certain points during the scan and will be able to answer your questions before or afterwards. During this time, general mobile phone usage is not permitted in the scanning room.

Who can I bring with me?

You are welcome to bring one other adult to the scan appointment.

Children are not permitted to attend scan appointments to avoid any distractions whilst the sonographer carries out important clinical checks and to enable parents to understand essential information.

A screening environment is also not appropriate for children as it can be distressing for them to see their parents being upset if problems with the baby are found.

There are no childcare facilities at the hospital. If there are exceptional circumstances and you are unable to arrange childcare, please contact the scan department to discuss this before your appointment.


If you would prefer to have a chaperone present throughout your scans, please inform your midwife when booking your appointment and we will do our best to arrange this for you.

How can I get pictures of my baby?

Parents are given the opportunity to buy an ultrasound image. They can be requested at any scan, although the view is dependent on baby’s position.

The length of the scan cannot be extended in order to obtain a ‘good’ picture.

Please note that thermal images should not be exposed to heat, such as being laminated, and the long-term stability of thermal images is unknown.

We ask that photographs or videos are not taken during the scan, using mobile phones or other recording equipment because:

  • If problems with the baby or pregnant woman/birthing person are identified during the scan, this can be very distressing and it is not appropriate to record or photograph
  • Sonographers require high levels of concentration during ultrasound examinations. Video recording and additional lighting from phones can be distracting and make it more difficult for the sonographer to see the screen
  • Privacy of our staff should be respected and they may wish not to be recorded

Can I find out my baby’s sex?

If requested by the pregnant woman/birthing person, sonographers are able to provide an opinion on the sex of the baby from the 20-week scan onwards.

Please note that this will depend on the position of the baby and other factors, so the sex cannot always be seen and opinions are not always accurate.

It is not a requirement of the NHS Fetal Anomaly Screening Programme to provide an opinion on the sex of a baby, so no additional time or additional appointments can be provided to look for the sex of the baby.

Sonographers cannot provide an opinion on the sex of the baby to anyone other than the woman/birthing person and their accompanying adult, and also not in an envelope for gender reveal purposes.

Your feedback matters

If you would like to give feedback on your care, please contact our patient experience team on paht.pals@nhs.net or 01279 827211.

Alternatively, you can contact the Maternity Voices Partnership, who work closely with us to represent your views and improve standards at the hospital, at mvpwestessex@gmail.com.

Inpatient comment:

Everyone offered words of such reassurance and kindness. I felt so cared for and the communication with me at all times was fantastic.