third trimester Ultrasound scan
When is it carried out?
- Routine third-trimester scans are usually performed to assess fetal growth and wellbeing and are carried out between 32+0-36+0 weeks but may be requested at any gestation between 24+0-40+0 weeks if there are risk factors in your current or previous pregnancies or your obstetrician is concerned about your baby’s growth.
- Please note that if you are attending for a third trimester scan but Dr To has not personally performed your second trimester scan, it is her policy to perform an assessment of the fetal anatomy. This will take 30 mins longer and be charged at the same price as a second trimester scan.
What is the purpose of the routine third-trimester scan?
- Confirm the fetal presentation (the part of the baby's body that is facing the birth canal) as this may influence the planned mode of delivery of the baby..
- Assess fetal growth and calculate an estimated fetal weight.
- Assess amniotic fluid volume and blood flow between the baby and the placenta (umbilical artery Doppler) and in the baby's brain (middle cerebral artery Doppler).
- Confirm placental position in cases where the placenta was found to be lying close to or covering the cervix (neck of the womb) at a prior scan. This may influence the planned mode of delivery of the baby.
What does it involve?
- An ultrasound scan (transabdominal).
Where does it take place?
How long does it take?
- Approximately 30 minutes
When are the results available?
- The results of the scan are available immediately and will be discussed with you after the scan and directly with your obstetrician if any urgent intervention is required. If more detailed counselling is required, it may be necessary to schedule this at a later date or at the end of the clinic, where possible.