Ultrasound scans are offered during pregnancy to check the baby's growth and development. They can be used to estimate the stage of pregnancy, check whether there is one baby or more, and examine the baby's anatomy and organs.

Ultrasound scans are optional and are considered safe for the pregnant woman and the baby.

Ultrasound scan at 12–14 weeks

The 12–14-week ultrasound scan is used to:

• Estimate how far along the pregnancy is and calculate the expected due date.

• Check whether there is one baby or more.

• Assess the baby's development and examine its anatomy as far as possible at this stage of pregnancy.

• The baby's nuchal translucency is measured, as increased nuchal translucency may indicate a chromosomal condition, congenital heart defect or other abnormality.

Increased nuchal translucency can indicate a possible abnormality, but does not necessarily mean that there is a problem. If anything unexpected is found during the ultrasound scan, information is provided about the findings and whether further tests may be needed.

Ultrasound scan at 19–20 weeks

By 19–20 weeks of pregnancy, the baby has grown enough for a more detailed examination of its organs and anatomy.

During this scan, the healthcare professional will:

• Check the baby's growth and development.

• Examine the structure of major organs, including the brain, heart, kidneys and spine.

• Check the position of the placenta and the amount of amniotic fluid.

• Look for possible differences in the baby's development or anatomy.

It is often possible to find out the baby's sex during this scan if requested.

Images from the scan are available for purchase. Please let the sonographer know at the beginning of the appointment if images are requested.

Additional ultrasound scans during pregnancy

Additional ultrasound scans may sometimes be needed to monitor the baby's growth, the amount of amniotic fluid or how well the placenta is functioning.

Specialist examinations, such as a fetal echocardiogram (a detailed ultrasound scan of the baby's heart) or Doppler ultrasound to assess blood flow, may also be needed. A midwife or doctor will assess whether further scans or tests are necessary and arrange them if needed.

• What can an ultrasound scan detect during pregnancy?

What happens during an ultrasound scan?

Ultrasound scans are performed by a midwife or doctor with specialist training in ultrasound.

Ultrasound gel is applied to the pregnant woman's abdomen, and a handheld probe is moved over the skin. An image of the baby appears on a screen, allowing those present to follow the examination.

Sometimes the probe needs to be pressed firmly against the abdomen to obtain a clearer image. Image quality can vary depending on factors such as the baby's position.

Ultrasound scan results

The results of an ultrasound scan are usually explained immediately afterwards.

Most ultrasound scans do not identify any concerns. If a possible difference in the baby's development or anatomy is identified, further ultrasound scans or other tests may be recommended.

However, a normal ultrasound scan does not guarantee that all conditions or abnormalities have been ruled out.

Preparing for the appointment

• The pregnant woman may bring one person to the ultrasound appointment.

• Children should not be brought to the appointment.

• Taking photographs or making video recordings during the scan is not permitted.

Cost

Ultrasound scans at 12–14 weeks and 19–20 weeks of pregnancy are free of charge.

Other screening and diagnostic tests

In some cases, Doppler ultrasound examinations are also performed to assess blood flow in the umbilical cord and the baby's blood vessels, particularly when closer monitoring of the baby's growth and wellbeing is needed.

Non-invasive prenatal testing (NIPT) is also available during pregnancy. This is a blood test that assesses the chance of certain chromosomal conditions in the baby. There is a fee for non-invasive prenatal testing (NIPT)

If ultrasound or NIPT results indicate that further testing may be needed, or if there is a known genetic condition in the family, prenatal diagnostic testing using chorionic villus sampling (CVS) or amniocentesis may be offered.