Third Trimester Ultrasound / Fetal Growth & Wellbeing

When is this scan usually performed?
A third trimester scan is carried out after 22-24 weeks gestation.

What is the purpose of this scan?
This scan is to look at;
• Size and growth of the baby
• Position of the baby
• Volume and fluid around the baby
• Placental position
• Review findings from a prior ultrasound

We can also assess blood flow through the umbilical cord (umbilical cord Doppler), Activity and movement of the baby (often termed biophysical profile) and the length of the cervix.

Why might I require this scan?
• If you have a medical condition (such as diabetes, increased blood pressure/pre-eclampsia, or heart disease)
• if you have a twin pregnancy
• if your baby is suspected to be large or small for your dates
• if your baby may be breech

What does the scan involve?
This scan takes around 20-30 minutes. It is performed by placing a probe and gel on the skin of your lower abdomen. Occasionally you will need a transvaginal scan (where a sterilised, covered probe is gently placed into the vagina whilst you are covered) This is sometimes required to more accurately assess the length of the cervix or the position of the placenta. It is less uncomfortable than a PAP smear.

Do I need a full bladder?
Your bladder needs to be partially filled (your bladder should not be so full that it causes you pain). Emptying the bladder an hour before the examination and drinking ¾ of a litre of water before your appointment is advised.

What if there is something wrong?
If there is a problem with your scan you will be informed of this at the time of your scan by a doctor and informed of what the next step will be. Occasionally a repeat scan is required at our practice or in a tertiary referral centre. These results will also be discussed with your referring doctor/midwife.

Will I have to return for further scans?
If a problem with your baby’s growth or the fluid around your baby is detected then a further scan/scans may be required to monitor this prior to delivery.

If you have any further questions do not hesitate to call us on 9399 5505 or ask the sonographer on the day of the scan.