An ultrasound scan can be used in several different ways, such as monitoring an unborn baby, diagnosing a condition or guiding a surgeon during certain procedures.

Pregnancy

Ultrasound scans are a routine procedure for pregnant women. They produce images of the unborn baby inside the womb and display them on a monitor.

Most women are offered at least two ultrasound scans during pregnancy:

• the first scan (at around 8-14 weeks) can help to confirm the pregnancy and determine when the baby is due
• the second scan (usually at around 18-21 weeks) checks for structural abnormalities, particularly in the baby's head or spine

However, an ultrasound scan can be done at any time during pregnancy and causes no harm to the baby.

Read more information about when ultrasound is used during pregnancy.

Diagnosing conditions

Ultrasound scans can help diagnose problems in many parts of your body, including your:

• liver (cirrhosis)
• gallbladder (gallstones)
• thyroid gland
• lymph nodes
• ovaries
• uterus (womb)
• testes
• breasts

For example, it can help to detect whether a lump in one of these organs is a tumour or a cyst.

Ultrasound may also be used to diagnose problems with your:

• blood vessels (aneurysm)
• joints, ligaments and tendons
• skin
• eyes

The hip, spine and brain of newborn babies can be scanned for abnormalities, but by 18 months old the skull has fully grown and it is no longer possible to use ultrasound on the brain without surgery.

Echocardiogram (ECG)

An ultrasound scan can be used to examine the size, shape and movement of your heart. For example, it can check that the structures of your heart, such as the valves and heart chambers, are working properly and your blood is flowing normally. This type of ultrasound scan is called an echocardiogram (ECG).

ECG can also be used to diagnose heart problems in babies, even before they are born. This is called foetal echocardiography, and is carried out during routine antenatal examinations. Read more about how congenital heart disease is diagnosed.

Biopsy

Ultrasound can be used to guide doctors during certain procedures, such as a biopsy (where a tissue sample is taken for analysis). This is to make sure the surgeon is working in the right area and is often used when diagnosing breast cancer.