An expert's guide to third trimester ultrasounds

Written in association with: Dr Spyros Bakalis
Published:
Edited by: Conor Dunworth

Third trimester ultrasounds are an important step in pregnancy, and can reassure the mother that her baby is growing healthily. In his latest online article, highly-experienced consultant in obstetrics and maternal and foetal medicine Dr Spyros Bakalis explains this scan in detail.

 

What exactly is a third trimester ultrasound scan?

A third-trimester ultrasound scan is a scan that takes place between 24 weeks and 42 weeks of pregnancy. The aim of the scan is to measure the size of the baby by measuring the head circumference, abdominal circumference and femur length.

The scan also allows us to review the blood flows of the baby, which flow from the baby to the placenta and back again, and to also check the amniotic fluid of the baby. These parameters allow us to reassure a mother that the baby is growing well and have we have no concerns regarding the placenta.

In addition to this, it allows us to review some of the baby's anatomy, specifically the brain, the kidneys and the bowel. Finally, if the baby's posing, it allows us to give the mother a good picture of her baby.

 

When is it necessary?

The third trimester scan is necessary when there are concerns regarding the baby's growth, or the movements of the baby.

In addition, in routine pregnancies which have no other complications, it is by far the best way to get a good estimate of the baby's weight and to ensure the baby is growing, and not suffering any complications in the womb.

 

Can you detail what exactly this third trimester ultrasound shows?

The third trimester ultrasound shows us the estimated weight of the baby. This allows us to plot the baby's weight on a chart and ensure the baby is growing appropriately. If there are any concerns about the baby's weight, it may make us reconsider delivery plans for the baby and mother.

 

How long does it usually take?

The third trimester ultrasound usually takes between 10 and 20 minutes.

 

How safe is it?

Ultrasounds are considered safe during pregnancy. Long-term studies do not show any complications for babies who are exposed to ultrasounds.

 

What should pregnant women be aware of before going for a third trimester ultrasound?

The vast majority of third trimester ultrasounds are uncomplicated, without any concerns regarding the baby. However, women need to be aware that occasionally we find a size change in the baby which may change management options for her pregnancy.

Secondly, women need to be aware that occasionally we do find a foetal abnormality which needs to be discussed further with the mother.

 

 

Dr Spyros Bakalis is a renowned consultant in obstetrics and maternal and foetal medicine. If you would like to book a consultation with Dr Spyros Bakalis you can do so today via his Top Doctors profile.

By Dr Spyros Bakalis
Obstetrics & gynaecology

Dr Spyros Bakalis is an extremely well-regarded consultant in obstetrics and maternal and fetal medicine who possesses expertise in conditions and areas such as multiple pregnancy, fetal and maternal medicine, childbirth, pregnancy, high-risk pregnancy, as well as the management of risk pregnancy and birthing. Presently, he practises at the London-based The Harley Street Centre For Women.

Dr Bakalis, who completed his undergraduate training at the highly established Guy's, King's and St Thomas' Medical School, was first appointed to the Guy's and St Thomas' Hospital in 2017, where he was given the crucial role in the fetal medicine unit, where he, since his appointment, has held the responsibility of carrying out various different therapeutic and diagnostic services. He has a particularly strong interest in growth complications in foetuses, as well as brain anomalies and placental abnormalities. 

Dr Bakalis successfully completed postgraduate training throughout both London as well as the West Midlands, during which he developed a vast amount of experience and expertise in relation to the management of both low-risk and high-risk pregnancies. He then decided to undertake research at the Harris Birthright Research Centre for Fetal Medicine, King’s College London, where he was deservedly awarded an MD for his extensive work.

Impressively, Dr Bakalis has also been officially accredited by the Royal College of Obstetricians and Gynaecologists with a subspecialty level of expertise in maternal and fetal medicine after undergoing training in all aspects of fetal and maternal medicine. 

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