How is an ultrasound examination performed?

Ultrasound waves are sent out from a transducer which is usually moved over the skin of the abdomen. Gel must be spread on the skin before the scan to allow the ultrasound waves to pass from the transducer into the body. There is no pain or other sensation from the ultrasound waves to either the person having the scan or the unborn baby. To obtain good views, at times pressure has to be applied to the transducer, but there is usually no more than mild discomfort.

The ultrasound examination may also be performed by placing a small transducer into the vagina. This transducer is narrow and usually causes minimal discomfort. This is used particularly in the early weeks of pregnancy, or to examine the uterus and ovaries in a woman who is not pregnant. The advantages of a vaginal scan are that a full bladder is not required, and it can provide more accurate information in some situations. In pregnancy this examination cannot harm the fetus - the transducer does not go into the uterus. Between patients, the transducer is cleaned and disinfected to prevent infection, and a protective cover applied. The transducer is inserted by the examiner, or you may prefer to insert it yourself as you would a tampon. If you wish to have a third person in the room for a vaginal scan, please let us know.

Is a full bladder needed?

With modern equipment a very full bladder is rarely required. Please note:

• In general it is useful if you could ensure that there is a little urine in your bladder at the time of the examination.
• If we suggest a vaginal scan we will ask you to empty your bladder.
• A very full bladder maybe required if you are either not pregnant or are in the early stages of pregnancy and you wish to avoid a vaginal scan.
• You may eat what you like before the examination.

Why is ultrasound used in pregnancy?

The most common reasons for your doctor to arrange an ultrasound examination during pregnancy are as follows:

• To calculate the due date,
• To see if there are twins
• To determine if the pregnancy is continuing normally when there has been bleeding in early pregnancy,
• To check the position of the placenta if there has been bleeding late in pregnancy,
• To check the physical development of the fetus and as far as possible to make sure there are no abnormalities,
• To see if the fetus is growing normally.

After the fourth month (18 weeks and onwards) better views are obtained of the fetal arms and legs, plus its organs, including the spine, stomach, heart and bladder. Many abnormalities, but not all, can be detected. While it is not possible to diagnose Down Syndrome (mongolism) with certainty using ultrasound, sometimes there are features seen on the scan which might raise a question of Down Syndrome. The policy of the practice is to be open and honest with you - if there is a problem detected you can be sure you will be told.

You will undoubtedly be impressed with the amount of fine detail visible with modern ultrasound equipment. However not all physical defects can be seen and no prenatal test can guarantee a 'perfect' baby.

What about 'social' ultrasound?

An ultrasound examination is performed only for valid medical reasons. All experts agree that it should not be performed merely for social reasons. When you come to our practice for a scan, however, we do everything we can to make the experience a pleasant one for you. Please tell us if you have any particular requests. We are happy to provide you with photos, a video, and if you wish to know the sex we will try to find out for you. You are welcome to bring friends and family but please be aware that children under 5 years rarely find the scan an enjoyable experience, and are best accompanied by another adult who can take them for a walk if they become restless.

Can ultrasound help with gynaecological problems?

Women who are not pregnant maybe referred for an ultrasound examination for a number of reasons such as:

• To try and determine the cause of pain in the lower abdomen or pelvis,
• if the gynaecologist finds a lump in the pelvis, a scan will often help to determine its nature,
• Abnormal vaginal bleeding, either before or after the menopause.

Why scan during invasive procedures?

An ultrasound gives a continuous picture, it is of great assistance in guiding a needle into areas deep within the body. Thus procedures such as amniocentesis and chronic villus sampling (C.V.S.), which are used to diagnose chromosome problems including Down Syndrome, are performed while watching the needle with ultrsound.

In patients who are pregnant, fluid may be removed from cysts in the ovary; and 'In Vitro Fertilisation' treatment, eggs are collected from the ovaries using ultrasound to guide the needle.

What do the pictures look like?

Ultrasound provides a picture of only one slice or section at a time. It is like looking at only one slice out of a loaf of bread. In this way pictures that are seen on the screen do not show the whole fetus at one time. A picture that shows the head and body is therefore unlikely to include the arms and legs. During the examination, every attempt will be made to show you the relevant features on the screen. The way the fetus is lying and a number of other factors can influence the clarity of the ultrasound picture. You can be sure that the ultrasound equipment used for your examination is the very best available for the purpose.

Summary

Ultrasound scanning is a very important method of assessing pregnancies. It can diagnose many of the complications which occur during pregnancy and provides information which can be vital in determining when and how best to deliver a baby.

The use of ultrasound in non-pregnant women with pain, bleeding, or with a suspected lump in the pelvis can provide very valuable information and in some will help avoid the need for an operation.

When you have an ultrasound examination, you should expect to be at the practice for approximately 1 hour.

If you have any questions please ask. If you would like more written infomation, we have pamphlets on procedures, including amniocentesis, C.V.S. and fetal blood sampling. More complete information is available in Lachlan's book titled "Prenatal Diagnosis: Which Tests For My Unborn Baby?" (OUP), which we have available at a reduced price.

Finally, it is important to us that we provide you with the best possible medical service in a pleasant atmosphere - we would be delighted to hear any comments you have. We cannot guarantee to be 100% accurate and to please everybody, but we aim to get as close to that as possible.