Pregnancy Ultrasound

Pregnancy Ultrasound


You are pregnant and your Midwife (LMC) 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 an 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 80 years in pregnancy. Ultrasound is considered safe, and there is no known side effects.

Will I need more than one scan?

Routine scans are performed in pregnancy at 12-13 weeks and again at 20 weeks.  Your LMC may recommend a scan at other times in your pregnancy to answer a specific question.

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 development and well-being, and to make sure the baby is growing normally. 

First trimester scans (before 12 weeks gestation) are often performed to assess the health of the forming pregnancy when there is pain or bleeding or to accurately determine gestational age when dates are uncertain. If you are unsure of your dates dating ultrasound is best performed at 8-10 weeks. 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.

The Nuchal Translucency assessment is performed between 12 weeks and 13 weeks 6 days. See Nuchal Translucency Scan.

At 20 weeks we will look specifically at the baby’s anatomy (how the baby has been formed), the fluid around the baby, the placenta and assess if the pregnancy is progressing normally.  This is the time we can usually determine fetal gender if desired.

Preparing for your scan

For certain types of scan, the gestational age 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 urine in the bladder to be used as a clear "viewing window" so the baby can be optimally seen. After 14 weeks, having a full bladder when you come for your appointment is not necessary.

Who will scan me?

The scan will be performed by the Sonographer (Technologist trained specifically in ultrasound).


What happens after my scan?

We will send a report of your scan to the person who referred you for your ultrasound (LMC) and your images will be available to you with the Hamilton My Images app.

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.


Are family or friends welcome?

Yes of course however the ultrasound room is only small and will only accommodate one extra support person. This will allow your sonographer to focus on producing a thorough examination for you and your baby.

The scan images will be available to you and your family through the Hamilton My Images app. Please ensure the receptionist has your mobile number to access these images. If you do not wish to receive these, please let us know.


Scans are performed either at the Anglesea Imaging Centre/Anglesea Women's Health (Thackeray Street), Rototuna Branch, Te Awamutu, Cambridge, Morrinsville or Mokoia Radiology in Rotorua.

Cost is $40 (NZ Residents) which is payable on the day before commencing the examination.

Phone Hamilton Radiology on 0800 HAMRAD (0800 426723) for an appointment.

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Postal Address: P O Box 262, Hamilton
Street Address: Gate 2, 11 Thackeray Street, Hamilton
Phone: (07) 839 4909
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