Pregnancy Ultrasound

You are pregnant and your Midwife or Doctor has suggested you have an ultrasound scan. You will have heard about ultrasound before, but may have some questions about ultrasound and your baby. This information is to help you with questions you may have.

What is ultrasound?

Ultrasound uses high frequency sound waves to see internal structures of the body. A hand held 'transducer' sends a brief pulse of sound into the body. When this sound reaches an internal structure it sends back a little echo. These echoes are seen as the images on the monitor of the ultrasound machine

Is the ultrasound safe?

Diagnostic ultrasound has been used for over 40 years in pregnancy. Current knowledge indicates that the benefits of the prudent use of diagnostic ultrasound for pregnant women, far out-weigh theoretical risks.

Will I need more than one scan?

More than one scan may be requested by your Lead Maternity Carer for a number of reasons. 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.

What happens after my scan? 

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

Why have ultrasound in pregnancy?

The most common reason to have ultrasound in pregnancy is to determine the age (gestation) of the baby, to confirm its well being, and 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 14 weeks gestation) the age is determined from calculations using the head, abdomen and upper leg measurements.

Reasons for Ultrasound in early pregnancy.

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 transducer placed in the vagina (an endovaginal scan). At the time of your appointment we will assess whether this is required and discuss this with you then.

When you are having an anatomy scan, we will look at the baby, the fluid around the baby and the placenta and assess if the pregnancy is progressing normally.

Preparing for your scan

For certain types of scan, the date may be very important to ensure the best measurements. Please be patient with the staff making the appointment.

If you are in the first 14 weeks of your pregnancy, you may be asked to have a full bladder for your scan. This allows the water in the bladder to be used as a clear "viewing window" so the baby can be seen. After 14 weeks, having a full bladder when you come for your appointment is not necessary.

How long will it take?

On average an ultrasound scan takes between 10 and 30 minutes. Factors that determine the length of the scan are the 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 an endovaginal scan is required.

Who will scan me?

The scan will be performed by either the Sonographer (skilled technician in ultrasound) or a Doctor who specialises in X-rays and ultrasound (Radiologist).

Will it hurt?

The ultrasound is not painful; although you may be uncomfortable if you need a full bladder. If you become too uncomfortable, please tell the reception staff; or if this happens during your scan, tell the Sonographer or Radiologist.

Are family or friends welcome?

Yes, but the ultrasound room will only accommodate a small number of people. If you would like to show your scan to others, you may wish to purchase a CD or USB  recording of your scan to take home.

Phone Mokoia Radiology on 0800 466 564 for an appointment.