Having a maternity ultrasound scan
Information for women, birthing people, and their families
This leaflet will explain the ultrasound services available to you during pregnancy. Speak with your midwife if you have any questions that are not covered by this leaflet.
What is an ultrasound scan?
Ultrasound scans use sound waves to build a picture of your baby in the womb. Your midwife will discuss ultrasound scans with you at your first (booking) appointment. If you agree to this type of screening they will arrange these for you. Ultrasound scans are used for the following.
Check the size of your baby. This gives a better idea of how many weeks pregnant you are. Your estimated due date is originally calculated from the first day of your last period. Your due date may be updated based on your ultrasound measurements.
Check whether you are having more than one baby.
Help with screening; detecting abnormalities where possible.
Check the position of your baby, and the placenta in the womb.
The sonographer will place some gel on your lower tummy. They will then pass a probe over the gel; an image will then appear on the screen. Ultrasound scans are painless. Occasionally, they may be a little uncomfortable if you have a very full bladder. They have no known side effects and can be carried out at any stage of pregnancy. Please talk to your healthcare professional about any concerns you have.
For many women or birthing people, ultrasound scans are the highlight of pregnancy. It is very exciting to ‘see’ your baby in the womb. Please be aware that ultrasound scans may also detect problems with the baby. You should try to be prepared for that information.
The sonographer will explain what they are checking at each stage of the scan. If any problems or abnormalities are found, or suspected, they will explain them to you. You will then be referred to the appropriate care team for further advice, if needed.
When will I have my scans?
You will be offered two ultrasound scans during your pregnancy. These will usually be:
12-week scan (from 11+2 to 14 weeks). May also be called the:
dating scan; or
NT scan.
20-week scan (from 18 to 20+6 weeks). May also be called the:
anomaly scan
mid-pregnancy scan; or
detailed scan.
You may be offered additional scans in your pregnancy. This will depend on your individual circumstances. You will be advised if and why this is necessary.
The first scan is sometimes called the dating scan. The sonographer estimates when your baby is due based on the baby's measurements. The dating scan can include additional tests, which are part of the combined test. This is screening for Down's, Edwards', and Patau’s syndromes. More information is available in the leaflet Screening tests for you and your baby.
The second scan is called the anomaly scan, or mid-pregnancy scan. This scan checks for any internal problems with your baby that can be seen at this time.
What happens on the day of my scan?
Please plan to arrive 15 minutes before your appointment time. Your appointment letter will tell you which hospital to come to. You will need to check-in with the receptionist when you arrive, this will vary according to location.
If you are late for your appointment, you may not be seen and will need to rearrange.
Please do not bring any children with you to your ultrasound scans. Your scans will need to be re-arranged if you arrive with any children.
Please do not empty your bladder (wee) on arrival. Your bladder should be reasonably, but not uncomfortably full. This can be very useful to improve the quality of the scan image.
You may find it helps to wear loose clothing. The sonographer will ask you to lie on your back and expose your tummy. This may mean they also ask you to:
open your trousers a little; or
pull them down a little.
This will mean enough of your tummy is exposed to perform the scan.
Who will perform my scan?
Your scan will be performed by a sonographer. A chaperone will also be present if the sonographer is male. A student may also be present. If you are not happy with this, please let the scan department know as soon as possible.
How long does a scan appointment take?
A scan usually takes around 20 to 30 minutes. However, it may take slightly longer if your baby:
is lying in a position that means it is hard to take measurements; or
is moving around a lot.
Will I need to have a blood test?
Yes, if you are consenting to first trimester screening, and all measurements have been completed.
This screening test is completed in 2 parts.
During the first part, you will have your ultrasound scan.
After the scan you will need to have a blood test taken. You will be given an appointment in the Phlebotomy department. If your scan is after 4pm or on the weekend:
a member of staff will take your blood in the scan room after your scan; or
you will be sent to triage / maternity day care to have your blood taken.
You will only need a blood test if we are able to obtain all the measurements needed during your scan. If this is not possible, you will be offered second trimester (14+2 to 20+0 weeks) screening. This involves either:
a blood test after 14 weeks and 2 days of pregnancy; or
a repeat scan around 16 weeks followed by a blood test.
More information is available in the Screening tests for you and your baby leaflet.
You will be advised what is needed by your sonographer. If you have any questions, please speak with your midwife or contact Maternity triage. Their number is at the bottom of this leaflet.
If you are worried about having a blood test, please speak with the health professional looking after you. They will discuss ways to support and reassure you.
It is very important that you have the blood test in order to complete the screening test. The results of the blood test will be given to you by your community midwife.
When will I get the results of the screening tests?
If you chose to have the combined or second trimester screening you will receive these results in the post. If you are found to have a 'high chance result' a specialist midwife will contact you by telephone.
We may need to refer you to a specialist if your scan findings are inconclusive. This means that the findings from your scan need further investigation.
I was told to have my scan plotted. What does this mean?
If you are 28 weeks pregnant or more you need to go to Maternity Triage after every scan. A midwife will plot the growth of your baby in your notes. Your baby’s growth will need to be plotted after every scan you have. This will help us make sure that there are no concerns with your baby’s growth.
Who can I bring with me to my scan?
You may like someone to come with you to your scan appointment. You can bring one person with you to support you.
Due to the nature of these screening scans, if an abnormality is found or suspected you may need this support. This environment is not appropriate for a child if this happens. They may become very distressed if you become upset. Due to the environment and the equipment in the room we are unable to supervise your children.
Children are not allowed to come to any scan appointments. If you arrive with a young child, your scan may need to be rearranged. We understand that for some people this can be very difficult. It is very important that you come to your ultrasound scan appointments. Please contact your midwife or the Ultrasound department as soon as possible if you feel reasonable adjustments need to be made. Their contact details can be found at the bottom of this leaflet.
Please do not attend the hospital or scan if you or your support person are unwell. Please contact the Ultrasound department or Maternity Triage for advice.
Can you tell me if I’m having a girl or boy?
If you want to find out the sex of your baby, you can usually do so during the 20-week scan. However, it is not always possible. Please tell the sonographer at the start of the scan that you wish to find out.
Please understand that the scan is a medical examination. Its main purpose is to look for structural problems or abnormalities with the baby. Finding out the sex of your baby is not its main purpose. The sonographer will not be able to 100 per cent confirm the sex of the baby.
Can I have a picture of my baby?
A copy of your baby scan photos can be provided at your 12- and 20-week scans.
Please note: filming is not allowed during your scan.
Do I have to have ultrasound scans?
No, not if you do not want to. We will respect your decision if you decide not to have the scans. Your antenatal care will continue as normal. Please discuss any concerns with your midwife at your first (booking) appointment.
What if I am told I need to have a transvaginal (internal) ultrasound scan (TVS)?
If you need to have a TVS, your midwife or doctor should have explained this to you before your appointment.
TVS are more commonly used during the very early weeks of pregnancy. There is a small chance that the sonographer may offer you this type of scan if baby cannot be seen clearly through your tummy.
A TVS is where a probe is inserted into your vagina to obtain detailed images of your cervix, uterus, or your baby. A TVS should not be painful but may be a little uncomfortable. You can ask the sonographer to stop at any time.
A TVS may also be recommended if:
you have more than one baby in your pregnancy; or
you are at increased risk of premature labour.
This type of scan is mostly used to measure any changes to your cervix. This includes the length of your cervix, or if your cervix is opening at all.
A chaperone will always be present during a TVS. You have the right to refuse this scan, or to ask more questions. Please speak to your midwife if you need more information about TVS.
How do I cancel and rearrange my ultrasound scan appointment?
Please contact us as soon as possible by calling the Ultrasound department. Their telephone number is 01233 616168. You can also call Maternity Triage; their number is below. You should select option 2 for the Ultrasound department.
We can then offer this date to another patient and agree a new appointment date and time with you.
It is very important to attend your first midwife (booking) appointment. If you do not attend, your ultrasound appointment may be cancelled. This can then cause a delay to your screening tests.
Useful contacts
If you have any further questions, please contact our Maternity Triage service on 01227 206737 for help and advice.
Call 01227 206 739 if you need to change a blood test appointment.
Call 01233 616168 (select option 2) if you need to speak with the Ultrasound department.
Further information
NHS: Screening tests in pregnancy. This video explains what to expect at your appointment in more detail.
How do I make a comment about my visit?
We aim to provide the best possible service. Staff will be happy to answer any questions you may have.
If you have any suggestions or comments about your visit, please:
speak to a member of staff; or
contact the Patient Advice and Liaison Service (PALS) on 01227 783145 or via email.
The PALS team will listen to your concerns, suggestions, or queries. They are often able to help solve problems on your behalf.
Ask 3 Questions
There may be choices to make about your healthcare. Before making any decisions, make sure you get the answers to these three questions:
What are my choices?
What is good and bad about each choice?
How do I get support to help me make a decision that is right for me?
Your healthcare team needs you to tell them what is important to you. It’s all about shared decision making.
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