How does a pregnancy ultrasound work?
Ultrasound uses high frequency sound waves to let us see internal structures of the body. A hand-held "transducer" (or probe) sends a brief pulse of sound into the body. When this sound reaches an internal structure it sends back an echo. These echoes are seen as the picture on the monitor of the ultrasound machine.

What are the risks?

Diagnostic ultrasound has been used for over 25 years in pregnancy. Current knowledge indicates that the benefits of the prudent use of diagnostic ultrasound for pregnant women far out-weigh possible risks.

Why have ultrasound during pregnancy?
The most common reasons to have ultrasound in pregnancy are to determine the age (gestation) of the baby, to confirm its well being and to make sure the baby is growing normally. In early pregnancy, we determine the age of your baby by measuring the length of the embryo. Later, after 16 weeks gestation, the age is determined from calculations using the head, abdomen and upper leg measurements. First trimester scans, within the first 12 weeks of pregnancy, are often performed to assess the pregnancy when there is pain or bleeding, or to determine gestation if you are unsure of your dates. Early in the pregnancy, we may need to scan with a special probe placed in the vagina (a transvaginal scan). At the time of your appointment we will assess whether this is required and discuss this with you. If you are having your scan at 18 to 20 weeks gestation, we will examine the baby, the fluid around the baby and the placenta and assess if the pregnancy is progressing normally.

Family is most welcome to join you, but please bear in mind the ultrasound room will only accommodate a small number of people. During your scan, images are recorded and these will be posted to you. If you do not wish to receive these, please let us know.

			Pre Examination
	Please phone us to make an appointment for your scan. If you are in the first 16 weeks of your pregnancy, you may be asked to have a full bladder for your scan. This allows the fluid in the bladder to be used as a clear "viewing window" so the baby can be seen. PREPARATION FOR YOUR ULTRASOUND EXAMINATION. If you have are over 12 weeks gestation and have had a previous scan in this pregnancy you do not need any preparation If you have not had a previous scan in this pregnancy and are under 12 weeks gestation you will need a full bladder. Please one hour before your scan empty your bladder and then immediately drink one litre (4 large glasses) of water. If you are under 12 weeks gestation and you have had a previous scan in this pregnancy, it is not necessary for you to have a full bladder when you come for your appointment.

			The Examination
	The scan will be performed by either a radiologist or a Sonographer. During your pregnancy, more than one scan may be requested by your doctor or lead maternity carer. This may be to visualise an area not seen adequately on a previous scan, to check the baby's growth or to see where the placenta is located before delivery of the baby. On average, an ultrasound scan takes between 10 and 30 minutes. Factors that determine the length of the scan are the gestation (age of the fetus), position of the baby in the uterus, how much fluid is present around the baby, how full the bladder is, the reason for the scan or whether a trans-vaginal scan is required.

			Post Examination
	We will send a report on your scan to the person who referred you for your ultrasound.