An ultrasound scan uses sound waves to create pictures of the inside of your body, such as muscles, organs or a baby in the womb, and it does not use radiation. The NHS offers ultrasound when a doctor or midwife needs one, including at least 2 scans in pregnancy. Private clinics also offer diagnostic scans and baby scans, and in England any clinic doing ultrasound scans, including keepsake baby scans, must be registered with the Care Quality Commission (CQC).
What an ultrasound scan is used for
The NHS says ultrasound scans can be used to:
- find out what is causing symptoms
- check on a condition you already have, such as a thyroid problem
- guide a doctor during some procedures
- check how a baby is developing during pregnancy
There are 3 main types of ultrasound scan:
- External: a probe is moved over your skin, above the part of the body being looked at
- Internal: a probe is placed inside the vagina or bottom (rectum)
- Endoscopic: a probe attached to a thin tube is passed into your food pipe (oesophagus), to give a clearer picture of things such as the heart or stomach
Pregnancy scans on the NHS
The NHS offers at least 2 ultrasound scans during pregnancy:
- a dating scan, sometimes called the 12-week scan, at 11 to 14 weeks
- a screening scan, sometimes called the anomaly scan or 20-week scan, between 18 and 21 weeks
You may be offered more than 2 scans, depending on your health and the pregnancy. The NHS says there are no known risks to the baby or the mother from having an ultrasound scan.
Finding out the sex of the baby is not part of the national screening programme. Some hospitals will tell you at the 20-week scan if you ask, but the NHS notes that the sonographer cannot be 100% certain.
NHS or private
On the NHS, ultrasound scans are arranged by the doctor, midwife or other health professional looking after you, and the report goes back to them.
Private clinics offer two broad kinds of scan:
- Diagnostic scans, which look at a particular part of the body to help find or monitor a problem
- Pregnancy and baby scans, which some parents book for reassurance or to get keepsake images
A private pregnancy scan does not replace the scans and checks in your NHS maternity care. Keep going to your NHS appointments, and tell your midwife if you have had a private scan.
Before booking a private scan, ask:
- who will carry out the scan and what their qualifications are
- who writes the report, and whether it will be sent to your GP or midwife
- what happens if the scan shows something that needs following up
- what the price includes
What happens during an ultrasound scan
Before the scan
The hospital or clinic should tell you if there is anything you need to do beforehand. Depending on the type of scan, you may be asked to drink water so your bladder is full, or to take off jewellery from the area being scanned.
During the scan
For an external scan, you lie on a bed and a slippery gel is put on your skin. The person doing the scan moves the probe over your skin, and the lights may be dimmed so they can see the screen clearly. You can ask them to stop at any time, or ask to change position if you are uncomfortable.
The NHS says most scans take around 10 to 45 minutes, but some take longer. The probe used for an external scan does not usually cause any pain. Internal probes can be uncomfortable when they are put in or moved during the test.
Results
You may get your results at the end of the appointment, or it can take a few weeks. The results are sent to the doctor who referred you, and you may need a follow-up appointment.
How to check a scan provider is registered
CQC guidance says the regulated activity of diagnostic and screening procedures includes all procedures that examine the body using ultrasound, including antenatal scans. This applies even to a scan done only for baby memorabilia or a keepsake, outside the maternity pathway, and whoever carries it out.
In England, a clinic offering any of these scans should be registered with the CQC. There are limited exceptions, such as ultrasound used by registered physiotherapists. You can search for a provider and read its latest rating on the CQC website.
Some people who carry out scans are registered professionals, such as radiographers registered with the Health and Care Professions Council (HCPC). You can search the HCPC Register by surname or registration number.
Find a clinic
Our diagnostic imaging guide lists ultrasound, X-ray and other scanning providers by city, with CQC ratings shown where available.
Sources: NHS: Ultrasound scan | NHS: Ultrasound scans in pregnancy | CQC: Diagnostic and screening procedures (scope of registration) | HCPC: Check the register.
Last reviewed: 6 October 2026. This guide is general information, not medical advice. In an emergency call 999. For urgent advice call NHS 111.