Pregnancy Guide

Ultrasound Scans

What is an ultrasound scan?

An ultrasound machine uses sound waves to create an image on a computer screen. The person who does the scan is called a sonographer. The sonographer will explain about the scan during your appointment.

How is the scan arranged?

If you decide you would like to have a scan, your midwife will tell you where it can be done and will arrange the appointment for you. If you have been given an appointment and then decide you do not want a scan, please tell your midwife and cancel the appointment.

How is the scan done?

The sonographer will get a clearer image of your baby if your bladder is not completely empty when you have your scan. Please try not to pass urine for about an hour before your appointment. For the sonographer to see your baby clearly on the screen, the scan is carried out in a dimly lit room. Scanning involves a lot of concentration so the room is also kept very quiet. The sonographers will explain to you what they are doing and what they are looking for. You will be asked to lie on your back to have the scan. You do not need to wear any specific clothing for the scans. However, you will be asked to raise your upper clothes to your chest and lower your skirt or trousers to your hips. Gel is spread on your lower abdomen so that a device called a transducer can be passed backwards and forwards over your abdomen. Ultrasound waves do not pass through air so the gel makes sure there is good contact between your skin and the transducer. Your clothing will be protected from the gel with tissue paper. The transducer passes sound waves through your abdomen into the womb. The sound waves bounce back off your baby and are translated into an image on a screen. An ultrasound scan is simple and painless. The sonographer may need to press on your abdomen to see your baby properly.

Are scans safe?

As far as we know, the early pregnancy dating scan and the fetal anomaly scan we offer are safe for mother and baby.

Further information

You can find out more information from:

Antenatal Screening Wales/ Sgrinio Cyn Geni Cymru | Antenatal Screening Tests


Last Updated: 08/11/2017 13:29:48
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website