Pregnancy ultrasound (antenatal ultrasound)
What is a 3-D and 4-D ultrasound?
Newer ultrasounds are now available that show a three-dimensional view of the foetus. This is similar in clarity to a photograph and can be useful in detecting birth defects when performed in a medical centre. A moving picture interpretation is referred to as a 4-D ultrasound. These scans are not usually offered on the NHS but can be obtained privately.
How should I prepare for an ultrasound?
There is no special preparation for the ultrasound test. Some doctors require you to drink 4 to 6 glasses of water before the test, so your bladder is full. This will help the doctor view the baby better on the ultrasound. You will be asked to refrain from urinating until after the test.
What happens during an ultrasound?
- You may be asked to change into a hospital gown.
- You will lie on a padded examination table during the test and a small amount of water-soluble gel is applied to the skin over your abdomen. The gel does not harm your skin or stain your clothes.
- A small device, called a transducer, is gently applied against the skin on your abdomen. The transducer sends high-frequency sound waves into the body, which reflect off internal structures, including your baby. The sound waves or echoes that reflect back are received by the transducer and transformed into a picture on a screen. These pictures can be printed out or sometimes recorded on a videotape.
- There is virtually no discomfort during the test. If a full bladder is required for the test, you may feel some discomfort when the probe is applied over the bladder.
- You may be asked to hold your breath briefly several times.
- The ultrasound test takes about 30 minutes to complete.
What happens after an ultrasound?
The gel will be wiped off your skin and your health professional will discuss the test results with you.