• The dating scan gives a better idea of how many weeks you are pregnant;
• Check whether you are having more than one baby;
• Detect structural abnormalities, unfortunately not all abnormalities are detectable with ultrasound;
• Calculate the risk of having a baby with a chromosomal abnormality like Downs syndrome;
• It shows the position of your baby and the placenta. The position of the placenta determines if vaginal delivery is possible or not;
• Check that the baby is growing normally;
• Check that there is enough amniotic fluid around the baby if there is enough space for the baby to grow in.

The sonographer will put ultrasound gel on your tummy and tuck a covering sheet and tissue paper around your clothing to protect it from the gel. The gel will provide a good contact between the probe and your tummy.

The sonographer passes a handheld device called a probe over your skin. It is the probe that sends out ultrasound waves and picks them up when they bounce back.

A black and white or sepia coloured image of the baby will appear on the ultrasound screen. During the examination the sonographer will need to keep the screen in a position that gives them a good view of the baby – either directly facing them or at an angle.

The sonographer will carefully and meticulously examine your baby’s body. Having the scan does not hurt, but the sonographer may need to apply some pressure to ensure the best views of the baby.

If you are overweight or your body tissue is dense, it can reduce the quality of the image as there is more tissue for the ultrasound waves to get through before they reach the baby. If it is difficult to get a good image, the scan may take longer or must be repeated another time.