Third Trimester Fetal Growth Scan

Third Trimester / Fetal Growth And Well-being Ultrasound

When is this scan usually performed?

A third trimester scan is carried out between 26-29 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.​

What does the scan involve?

This scan takes around 10-20 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.