Ultrasound uses sound waves to create images of the organs and tissues inside the body. It's also called sonography or ultrasonography and the person who carries out an ultrasound scan is called a sonographer for that reason.

Ultrasound is non-invasive and painless and, because it uses sound waves rather than radiation, it's considered safe. This makes it particularly good for pregnancy scans.

Ultrasound is high frequency sound waves that cannot be heard by the human ear.  A probe transmits short pulses of high frequency ultrasound into the body and within a fraction of a second receives back multiple echoes from the part of the body being examined. These echoes are then converted into images, which allow the sonographer and doctor to see the organs and tissue in detail.

• Pregnancy. Ultrasound is an important part of pregnancy (obstetric) care. It's used to check how your baby is developing, identify gender and date your pregnancy. The majority of pregnancies are normal and healthy, but ultrasound is also used to test for any abnormalities that may affect your baby. The scans offer reassurance at all stages of your pregnancy and cause no harm to your baby.

• Gynaecology. Ultrasound scans are used to take images of the womb (uterus), ovaries and other organs within the pelvis. It can help with gynaecological problems and identify the source of pain or bleeding and has an important role in the early detection of pelvic (ovarian) cancers.

• General. Ultrasound can help to diagnose problems of the liver, gallbladder, pancreas, kidneys and other organs. It's often used to detect gallstones and kidney stones and to identify the cause of abdominal pain.

• Cancer. Ultrasound is used to locate tumours in soft-tissue organs, often from an early stage of development. It can usually be used to distinguish between malignant and non-malignant damage within the major organs. Doctors can also use ultrasound to guide them during a biopsy (removal of tissue using a needle).
  

3D ultrasound produces three-dimensional shapes of the organs within the body. It's particularly useful as part of internal (transvaginal) scanning.

4D ultrasound produces moving 3D images. It's widely used in pregnancy scanning to show the baby's external features more clearly, particularly the baby's face.
All our ultrasound scans are either 3D or 4D.

Doppler scanning is a special ultrasound technique used to view blood flow through the organs and major blood vessels. It's very useful for investigating vascular (blood vessel) disease and can also show abnormal blood flow associated with infection or tumours.

Our machines use colour Doppler scanning.

Duplex Doppler combines traditional ultrasound with Doppler scanning and is most commonly used to check blood flow through arteries and veins. We routinely use this during pregnancy scans to see the blood flow through the umbilical cord.

An internal (transvaginal) scan gives clearer images of the womb, ovaries and pelvis. It's used to find the cause of fertility problems, abnormal vaginal bleeding or pelvic pain. A narrow probe is used, which is gently inserted a few centimetres into the vagina. The scan is safe and does not cause discomfort for most patients.

For most scans you don't need to do anything beforehand. But, we'll let you know what to do depending on the type of scan you're having. For example, we'll ask you not to eat or drink anything for four hours prior to an abdominal scan.

You may feel most comfortable wearing loose-fitting clothes for your scan, but we do have gowns that you can change into.

You'll meet one of our sonographers who is trained and experienced in the type of scan you're having. They'll apply a gel to the area of your skin where you'll have your scan. This gel maximises the contact between the scanning probe and your skin to produce high quality images. The scanning probe is similar to a microphone and your sonographer will move this over the area they're scanning. They may ask you to lie still, change your position, hold your breath or perform very simple breathing exercises during your scan.

Once the scan is complete your sonographer will help you wash off the gel, check the images and will explain the results to you. They'll also let you know what you need to do next.

Most scans take 30-45 minutes, but more complex scans and multiple pregnancies will take longer. We'll let you know how long your scan is likely to take when you book. But, we never rush an ultrasound scan, so we generally recommend you allow one hour for your appointment.

We'll discuss the results of your scan with you at your appointment. We'll then send a full report to your doctor within 24 hours. In urgent cases, your sonographer will telephone him/her to give them the results sooner. If you'd like a copy of your report please let us know.

If you've had a blood test you'll get the results:

• at the same time as your scan if your blood sample was taken more than 24 hours before your scan
• the next day if it was taken the same day as your scan.
  

You're welcome to bring a relative or friend with you. If you're coming alone and would like a chaperone please tell us when you make your appointment and we can arrange for a member of our team to sit in during your scan.

We can usually identify your baby's gender from around 13 weeks, providing they're in the right position during your scan.

We won't tell you your baby's gender unless you want to know, so there's no pressure to find out at this stage. We can still identify the gender during the later scans from 20 weeks.

This is the earliest pregnancy ultrasound scan and can be done when you're 5-11 weeks pregnant. It's also called the dating scan because we can use it date your pregnancy and estimate when your baby is due. Although it's not offered by the NHS many women choose to have it, as it confirms that they're pregnant, dates their pregnancy and offers reassurance if they've had pregnancy complications in the past.

This scan can be done between 18and 24 weeks. It's an important part of your prenatal care, as it allows us to see how your baby is developing, because it's the first scan where we can see your baby's anatomy in detail.

This scan is also used to look for abnormalities, which is why it's often referred to as the anomaly scan. However, the majority of pregnancies are healthy, so our main concern is to measure your baby's anatomy and growth, as well as look for signs of any disorders.

The welfare scan is used to confirm that your baby is growing normally and is done between 26 and 40 weeks. It's recommended whenever the pregnancy is healthy and developing normally and we want to confirm the baby is growing normally. You may also choose to have this scan if your baby has been moving less than before, or if you've experienced unusual abdomen pains or any bleeding.

Also referred to as non-invasive prenatal diagnosis (NIPD) or prenatal fetal DNA testing, this a new test used to detect Down syndrome and other chromosome abnormalities, such as trisomies 13 and 18. It's greater than 99% accurate and, effectively, replaces amniocentesis as it can be done very early in your pregnancy.

The test is done by taking a blood sample from the mother, making it non-invasive and safe for both her and the baby.

The nuchal scan allows us to assess your baby's risk of having a genetic or chromosome disorder, such as Down syndrome, but is also is very useful in confirming normal fetal development early in pregnancy. There are two parts:

• an ultrasound scan and
• a blood test using a sample of the mother's blood.

The nuchal scan measures nuchal translucency, which is a small amount of fluid beneath the skin at the back of your baby's neck. This measurement is used together with the blood test to calculate your risk level and help you decide if you should consider a more accurate test such as non-invasive prenatal testing (NIPT), or genetic amniocentesis. At the time of the nuchal scan, a thorough evaluation is also performed of the rest of your baby to confirm normal development and that other aspects of your pregnancy are normal.

Amniocentesis is a test used to diagnose genetic or chromosome conditions in an unborn baby, such as Down syndrome. A fine needle is used to take a sample of the amniotic fluid that surrounds the baby inside the womb (uterus). The fluid is tested in a lab. Amniocentesis is usually carried out between 15-18 weeks into the pregnancy and is usually offered to women who are at risk and who have not had the non-invasive prenatal test. Amniocentesis carries a small risk of complications, including miscarriage. We do not currently offer amniocentesis.

Chorionic villus sampling (CVS) is a test used to diagnose genetic or chromosome conditions in an unborn baby, such as Down syndrome. It's done by taking a very small sample of the tissue from the placenta, as these cells have the same genetic material as the developing baby. CVS is usually carried out between 11-13 weeks into pregnancy. CVS carries a small risk of complications, including miscarriage. We do not currently offer CVS.