Ultrasound scans

An ultrasound scan is a way of looking at your baby in the womb. Scans are painless and can check the size and growth of your baby and show whether you are having more than 1 baby.

You will be offered 2 ultrasound scans between 11-14 and 18-21 weeks as part of your antenatal care. Some hospitals offer extra scans, for example to check your baby’s growth. Like all the other tests and procedures, you can choose whether to have these scans.

Seeing your baby for the first time can feel like an exciting event. You may feel anxious too. You can bring your partner, a friend or a family member to your scans. Most hospitals do not let you take children to these scans but you can check this with your midwife.

How do ultrasound scans work?

An ultrasound scan uses sound waves to show your baby on a screen. They do not cause any harm you or your baby.

During the scan, you will lie on your back on an examining table. The scanner (sonographer) will spread a gel over your stomach and then roll a small scanning device around the area where the gel is. This sends pictures of your baby to a computer screen.

Some hospitals will print a picture of your baby for you to keep, but in some places you may need to pay a small fee for it.

Where will I have my ultrasound scans?

Most people have their ultrasound scans at their local NHS hospital. There are also independent (private) baby scanning services that offer ultrasound scans. These will charge you a fee for doing the scan.  

All ultrasound scanning services that check your baby’s health must be registered with the Care Quality Commission (CQC). If the service is not registered they may be practising illegally and without the right insurance.  The CQC have more information about choosing a baby scanning service

What are the scans looking for in pregnancy?

At 11 to 14 weeks

The dating scan:

At 18 to 21 weeks

This scan, known as the 20-week or fetal anomaly scan shows:

  • how your baby is growing
  • the health and position of your placenta
  • if there are any visible problems with the way your baby’s body is developing.

Most scans show that the baby is developing normally because most babies are healthy. But sometimes the scan may show that your baby may have a health condition.  

The scan cannot pick up all health conditions so it is important to speak to your midwife if you have any symptoms that worry you or feel that something is not right.

When can I tell if I am having a boy or girl?

At your 20-week scan, the sonographer may be able to see if your baby is a boy or a girl.

Tell them if you would like to know – and tell them too if you do not want to find out until the birth.

Keep in mind that the reason for the scan is to check the health and growth of your baby and some hospitals may have a policy of not telling parents the baby’s sex. Your baby may also be lying in a position that does not let the sonographer see the sex.

Can I have extra scans during my pregnancy?

You will usually only need 2 scans if you are expecting 1 baby and do not have any complications. Your midwife or doctor may offer you more scans if they are needed, for example to check your baby’s position in the womb or if there are concerns about your baby’s growth.

Some independent scanning services offer souvenir scans, with pictures or videos for you to keep. There are no known risks to having extra scans.  Be aware that while these scans can detect (find) a pregnancy, they cannot guarantee or predict how your pregnancy will progress.

If there is no medical reason for having an early scan, it may help to think about how you feel about the idea and if it would help you or increase any anxiety you may be feeling about your pregnancy

Some people have extra scans in the early weeks of pregnancy because they have miscarried before. These are sometimes known as early pregnancy scans, reassurance scans or viability scans. Find out more about early pregnancy scans after a miscarriage.

There is information here about how to ease anxiety in a pregnancy after a previous miscarriage.

What if I am expecting twins or more?

You will be offered extra scans in pregnancy if the first scan shows you are expecting more than 1 baby. You will be looked after by a team of doctors and midwives who specialise in multiple pregnancies.

At the first scan, the scanner will check to see whether your babies share a placenta. This is because it will have an impact on what type of care you will have in pregnancy and when you give birth.

Find out more about multiple pregnancies and giving birth to multiple babies.  

Care Quality Commission. (2022) Choosing a baby scanning service. https://www.cqc.org.uk/care-services/help-choosing-care/choosing-baby-scanning-service  

NHS. Antenatal care with twins. https://www.nhs.uk/pregnancy/your-pregnancy-care/antenatal-care-with-twins/ (Page last reviewed: 14 October 2022. Next review due: October 2025)

NHS. Ultrasound scans in pregnancy. https://www.nhs.uk/pregnancy/your-pregnancy-care/ultrasound-scans/ (Page last reviewed: 9 December 2020. Next review due: 9 December 2023)  

NHS England. (2022) 11 physical conditions (20-week scan). https://www.gov.uk/government/publications/screening-tests-for-you-and-your-baby/11-physical-conditions-20-week-scan  

National Institute for Health and Care Excellence (2019). Twin and triplet pregnancy. NICE guideline [NG137]. https://www.nice.org.uk/guidance/ng137  

National Institute for Health and Care Excellence (2023). Antenatal care - uncomplicated pregnancy: Scenario: Antenatal care - uncomplicated pregnancy. NICE clinical knowledge summary. https://cks.nice.org.uk/topics/antenatal-care-uncomplicated-pregnancy/management/antenatal-care-uncomplicated-pregnancy/  

Public Health England. (2021) Screening in pregnancy: dating scan. https://www.gov.uk/government/publications/early-pregnancy-scan-brief-description/fetal-anomaly-screening-pregnancy-dating-scan  

Review dates
Reviewed: 29 June 2023
Next review: 29 June 2026